View source for Biology:Ug99

{{Short description|Worst wheat disease. Race of stem rust.}}
{{Taxobox
| name = ''Puccinia graminis''
| image= Stem rust close up.jpg
| image_width = 250px
| regnum = [[Biology:Fungi|Fungi]]
| phylum = [[Biology:Basidiomycota|Basidiomycota]]
| classis = [[Biology:Pucciniomycetes|Pucciniomycetes]]
| subclassis = [[Biology:Incertae sedis|Incertae sedis]]
| ordo = [[Biology:Pucciniales|Pucciniales]]
| familia = [[Biology:Pucciniaceae|Pucciniaceae]]
| genus = ''[[Biology:Puccinia|Puccinia]]''
| species = '''''P. graminis'''''
| subspecies = '''''P. graminis tritici'''''
| varietas = Ug99
}}
'''Ug99''' is a lineage of wheat [[Biology:Stem rust|stem rust]] (''Puccinia graminis'' f. sp. ''tritici''), which is present in [[Biology:Wheat|wheat]] fields in several countries in [[Earth:Africa|Africa]] and the [[Place:Middle East|Middle East]] and is predicted to spread rapidly through these regions and possibly further afield, potentially causing a wheat production disaster that would affect [[Earth:Food security|food security]] worldwide.<ref name=Singh11 /> In 2005 the noted green revolution pioneer [[Biography:Norman Borlaug|Norman Borlaug]] brought great attention to the problem, and most subsequent efforts can be traced to his advocacy.<ref name="Gross-2013">{{cite journal | last=Gross | first=Michael | title=Pests on the move | journal=[[Biology:Current Biology|Current Biology]] | publisher=Cell Press | volume=23 | issue=19 | year=2013 | issn=0960-9822 | doi=10.1016/j.cub.2013.09.034 | pages=R855–R857 | pmid=24251330 | s2cid=15559913| doi-access=free }}</ref> It can cause up to 100% crop losses and is [[Biology:Virulence|virulent]] against many [[Biology:Stem rust#Wheat stem rust resistance genes|resistance genes]] which have previously protected wheat against stem rust.

Although Ug99-[[Biology:Plant disease resistance|resistant]] varieties of wheat do exist,<ref name="Gross-2013" /> a screen of 200,000 wheat varieties used in 22 African and Asian countries found that only 5-10% of the area of wheat grown in these countries consisted of varieties with adequate resistance.<ref name=Singh11 />

The original race of Ug99, which is designated as 'TTKSK' under the North American nomenclature system, was first detected in Uganda in 1998<ref name="Pretorius-et-al-2000-bundle">
   {{Unbulleted list citebundle
      |{{*}} {{cite journal | last1=Pretorius | first1=Z. A. | last2=Singh | first2=R. P. | last3=Wagoire | first3=W. W. | last4=Payne | first4=T. S. | title=Detection of Virulence to Wheat Stem Rust Resistance Gene ''Sr31'' in ''Puccinia graminis''. f. sp. ''tritici'' in Uganda | journal=Plant Disease | publisher=[[Organization:American Phytopathological Society|American Phytopathological Society]] | volume=84 | issue=2 | year=2000 | issn=0191-2917 | doi=10.1094/pdis.2000.84.2.203b | pages=203 | pmid=30841334 | s2cid=73469939}}
         |{{*}} {{ Cite journal|year=2012|issue=4|volume=13|publisher=[[Company:Wiley-Blackwell|Wiley-Blackwell]]|first11=Gary|first10=Jeff|first9=Regine|first8=Marty|first7=Jason|first6=Pietro|first5=Antonio|first4=Kim|first3=Zacharias|first2=Jan|first1=Ralph|last11=Foster|last10=Ellis|last9=Kahmann|last8=Dickman|last7=Rudd|last6=Spanu|last5=Pietro|last4=Kosack|last3=Pretorius|last2=Kan|last1=Dean|pages=414–430|title=The Top 10 fungal pathogens in molecular plant pathology|journal=[[Biology:Molecular Plant Pathology|Molecular Plant Pathology]] |issn=1464-6722|doi=10.1111/j.1364-3703.2011.00783.x|pmc=6638784|pmid=22471698|s2cid=18505064}}
         |{{*}} {{ Cite journal
 |   last1=Singh
 |  first1=Ravi P.
 |   last2=Hodson
 |  first2=David P.
 |   last3=Huerta-Espino
 |  first3=Julio
 |   last4=Jin
 |  first4=Yue
 |   last5=Bhavani
 |  first5=Sridhar
 |   last6=Njau
 |  first6=Peter
 |   last7=Herrera-Foessel
 |  first7=Sybil
 |   last8=Singh
 |  first8=Pawan K.
 |   last9=Singh
 |  first9=Sukhwinder
 |  last10=Govindan
 | first10=Velu
 | title=The Emergence of Ug99 Races of the Stem Rust Fungus is a Threat to World Wheat Production
 | journal=[[Biology:Annual Review of Phytopathology|Annual Review of Phytopathology]]
 | publisher=Annual Reviews
 | date=8 September 2011
 | volume=49
 | issue=1
 | pages=465–481
 | doi=10.1146/annurev-phyto-072910-095423
 | pmid=21568701
 | s2cid=24770327
 | issn=0066-4286
 }}
         |{{*}} {{ Cite book | last1=Singh | first1=Ravi P. | last2=Hodson | first2=David P. | last3=Huerta-Espino | first3=Julio | last4=Jin | first4=Yue | last5=Njau | first5=Peter | last6=Wanyera | first6=Ruth | last7=Herrera-Foessel | first7=Sybil A. | last8=Ward | first8=Richard W. | title=Advances in Agronomy | chapter=Will Stem Rust Destroy the World's Wheat Crop? | publisher=[[Company:Elsevier|Elsevier]] | year=2008 | volume=98 | issn=0065-2113 | doi=10.1016/s0065-2113(08)00205-8 | pages=271–309/xiii+422 | isbn=9780123743558 | s2cid=55174564}}
   }}
</ref> and first characterised in 1999<ref name="Pretorius-et-al-2000-bundle" /> (hence the name Ug99) and has since been detected in Kenya, Ethiopia, Eritrea, Sudan, Yemen, [[Religion:Iran|Iran]], Tanzania, Mozambique, Zimbabwe, {{wipe|South Africa}},<ref name="Hodson12">{{cite web|first1=D. P. |last1=Hodson |first2=J. |last2=Grønbech-Hansen |first3=P. |last3=Lassen |first4=Y. |last4=Alemayehu |first5=J. |last5=Arista |first6=K. |last6=Sonder |first7=P. |last7=Kosina |first8=P. |last8=Moncada |first9=K. |last9=Nazari |first10=R. F. |last10=Park |first11=Z. A. |last11=Pretorius |first12=L. J. |last12=Szabo |first13=T. |last13=Fetch |first14=Y. |last14=Jin|title=Tracking the Wheat Rust Pathogens|url=http://wheatrust.org/fileadmin/www.grcc.au.dk/Publications/Hodson_BGRI2012.pdf|work=2012 Borlaug Global Rust Initiative Technical Workshop Proceedings|publisher=[[Earth:Borlaug Global Rust Initiative|Borlaug Global Rust Initiative]]|access-date=28 November 2012|archive-url=https://web.archive.org/web/20191005184722/http://wheatrust.org/fileadmin/www.grcc.au.dk/Publications/Hodson_BGRI2012.pdf |archive-date=October 5, 2019 |url-status=live}}</ref> and [[Place:Egypt|Egypt]]. There are now 15 known races of Ug99.<ref name="Rust-Tracker">{{cite web |url=http://rusttracker.cimmyt.org/?page_id=22 |title=Pathotype Tracker – Where is Ug99? |publisher=The International Maize and Wheat Improvement Center}}</ref>  They are all closely related and are believed to have [[Biology:Evolution|evolved]] from a common ancestor, but differ in their [[Biology:Virulence|virulence]]/avirulence profiles and the countries in which they have been detected.<ref name=Singh11 />

== Genetics ==
Ug99 is the product of a type of somatic nuclear exchange event which has not been observed in other stem rust races.<ref name="Li-et-al-2019">{{cite journal |last1=Li |first1=Feng |last2=Upadhyaya |first2=Narayana M. |last3=Sperschneider |first3=Jana |last4=Matny |first4=Oadi |last5=Nguyen-Phuc |first5=Hoa |last6=Mago |first6=Rohit |last7=Raley |first7=Castle |last8=Miller |first8=Marisa E. |last9=Silverstein |first9=Kevin A. T. |last10=Henningsen |first10=Eva |last11=Hirsch |first11=Cory D. |last12=Visser |first12=Botma |last13=Pretorius |first13=Zacharias A. |last14=Steffenson |first14=Brian J. |last15=Schwessinger |first15=Benjamin |date=2019-11-07 |title=Emergence of the Ug99 lineage of the wheat stem rust pathogen through somatic hybridisation |journal=Nature Communications |publisher=[[Company:Nature Portfolio|Nature Portfolio]] |volume=10 |issue=1 |page=5068 |bibcode=2019NatCo..10.5068L |doi=10.1038/s41467-019-12927-7 |issn=2041-1723 |pmc=6838127 |pmid=31699975 |last16=Dodds |first16=Peter N. |last17=Figueroa |first17=Melania |s2cid=207916981}}
</ref> During this event and thereafter the nuclei have not experienced [[Biology:Genetic recombination|recombination]].<ref name="Li-et-al-2019" />

== Gene resistance ==
Ug99 and its variants differ from other strains of the Black Stem Rust (BSR) pathogen due to their ability to overcome resistance genes in wheat that have been durable against the BSR pathogen for decades.<ref name="USDA Coordinated Approach to Address Pgt-Ug99">{{cite web |title=USDA Coordinated Approach to Address Pgt-Ug99 |publisher=ARS (USDA [[Organization:Agricultural Research Service|Agricultural Research Service]])|date=September 20, 2017 |url=https://www.ars.usda.gov/ug99/}}</ref> These resistant ''Sr'' genes, of which 50 are known, give wheat different resistances to stem rust.<ref name="Pretorius-et-al-2000-bundle" /> The virulence in Uganda was virulent against ''Sr31'' and is specific to Ug99.<ref name="Pretorius-et-al-2000-bundle" /> The massive losses of wheat that have occurred have been devastating, but in recent years the wheat rust epidemic has been effectively controlled through selection and breeding for additional ''Sr'' genes.<ref name="Pretorius-et-al-2000-bundle" /> (In the decades since, however, ''Sr31''-virulence has evolved in other strains in other locations.<ref name = "Return-to-Europe" /> Patpour ''et al.'', 2022 finds it in {{wipe|Spain}} and Siberia.)<ref name = "Return-to-Europe" >
 {{ Unbulleted list citebundle
    |{{*}} {{ Cite journal
              | language    = English
              | year        = 2022
              | doi-access  = free
              | publisher   = Springer Nature B.V.
              | issue       = 6
              | volume      = 14
              | pages       = 1475–1497
              | first7      = Anders
              | first6      = Jim
              | first5      = Anne
              | first4      = Ivar
              | first3      = Anna
              | first2      = Beth
              | first1      = Djurle        
              | last7       = Kvarnheden
              | last6       = Nygren
              | last5       = Blomstrom
              | last4       = Vågsholm
              | last3       = Berlin
              | last2       = Young
              | last1       = Annika
              | title       = Addressing biohazards to food security in primary production
              | issn        = 1876-4517
              | eissn       = 1876-4525
              | journal     = Food Security
              | s2cid       = 250250761
              | doi         = 10.1007/s12571-022-01296-7
              | id          = AD {{ORCID|0000-0003-1830-6406}}, AB {{ORCID|0000-0002-9518-5719}}, IV {{ORCID|0000-0002-1661-0677}}, ALB {{ORCID|0000-0003-4455-311X}}, AK {{ORCID|0000-0001-9394-7700}}
           }}
    |{{*}} {{ Cite journal
              | language    = English
              | year        = 2022
              | doi-access  = free
              | publisher   = Frontiers Media SA
              | volume      = 13
              | id          = 882440
              | page        = 882440
              | first19     = Anne
              | first18     = Jens
              | first17     = Tine 
              | first16     = Romain 
              | first15     = Kevin
              | first14     = Les 
              | first13     = Yue 
              | first12     = Ekaterina
              | first11     = Svetlana 
              | first10     = Alena
              | first9      = Pawel 
              | first8      = Kerstin 
              | first7      = Anna 
              | first6      = Vladimir
              | first5      = Dolors 
              | first4      = Biagio 
              | first2      = Mogens
              | first3      = Julian 
              | first1      = Mehran 
              | last19      = Justesen
              | last18      = Hansen
              | last17      = Thach
              | last16      = Valade
              | last15      = Meyer
              | last14      = Szabo
              | last13      = Jin
              | last12      = Skolotneva
              | last11      = Slikova
              | last10      = Hanzalova
              | last9       = Czembor
              | last8       = Flath
              | last7       = Berlin
              | last6       = Shamanin
              | last5       = Villegas
              | last4       = Randazzo
              | last3       = Rodriguez
              | last2       = Hovmoller
              | last1       = Patpour
              | journal     = Frontiers in Plant Science
              | issn        = 1664-462X
              | oclc        = 731659269
              | s2cid       = 249244042
              | pmc         = 9202592
              | pmid        = 35720526
              | doi         = 10.3389/fpls.2022.882440
              | title       = Wheat Stem Rust Back in Europe: Diversity, Prevalence and Impact on Host Resistance
           }}
 }}
</ref>

United States Department of Agriculture ([[Organization:USDA|USDA]]) researchers are testing genes to determine their Ug99 resistance, which will ultimately aid in the development of wheat varieties that will be able to fight off the rust. Resistance has been identified in a small number of spring wheat land races from [[Earth:North America|North America]] - 23 out of 250 races with adult plant resistance, 27 out of 23,976 SNPs conveying APR, and only 9 races having seedling resistance.<ref name="Bajgain-et-al-2015-bundle">
  {{Unbulleted list citebundle
   | {{*}} {{cite journal | last1=Bajgain | first1=P. | last2=Rouse | first2=M. N. | last3=Bulli | first3=P. | last4=Bhavani | first4=Sridhar | last5=Gordon | first5=T. | last6=Wanyera | first6=R. | last7=Njau | first7=P.N. | last8=Legesse | first8=W. | last9=Anderson | first9=J. A. | last10=Pumphrey | first10=M. O. | title=Association mapping of North American spring wheat breeding germplasm reveals loci conferring resistance to Ug99 and other African stem rust races | journal=BMC Plant Biology | publisher=[[Company:BioMed Central|BioMed Central]] | volume=15 | issue=1 | date=2015-10-14 | issn=1471-2229 | doi=10.1186/s12870-015-0628-9 | page=249 | pmid=26467989 | pmc=4606553 | s2cid=54521938 | doi-access=free}}
      | {{*}} {{cite journal | last1=Kumar | first1=Jitendra | last2=Gupta | first2=Debjyoti Sen | last3=Gupta | first3=Sunanda | last4=Dubey | first4=Sonali | last5=Gupta | first5=Priyanka | last6=Kumar | first6=Shiv | title=Quantitative trait loci from identification to exploitation for crop improvement | journal=[[Chemistry:Plant Cell Reports|Plant Cell Reports]] | publisher=[[Company:Springer Science+Business Media|Springer Science+Business Media]] | volume=36 | issue=8 | date=2017-03-28 | issn=0721-7714 | doi=10.1007/s00299-017-2127-y | pages=1187–1213 | pmid=28352970 | s2cid=25627600| url=https://mel.cgiar.org/reporting/download/hash/EseurVAQ }}
      | {{*}} {{cite journal|publisher={{wipe|John Wiley & Sons}}|id=[[Organization:Society for Experimental Biology|Society for Experimental Biology]] (SEB)| last1=Scheben | first1=Armin | last2=Verpaalen | first2=Brent | last3=Lawley | first3=Cynthia T. | last4=Chan | first4=Chon‐Kit K. | last5=Bayer | first5=Philipp E. | last6=Batley | first6=Jacqueline | last7=Edwards | first7=David | title=CropSNPdb: a database of SNP array data for ''Brassica'' crops and hexaploid bread wheat | journal=The Plant Journal| volume=98 | issue=1 | date=2019-01-28 | issn=0960-7412 | doi=10.1111/tpj.14194 | pages=142–152 | pmid=30548723 | s2cid=56486847}}
      | {{*}} {{cite journal|publisher=John Wiley & Sons, Inc.| last1=Bajgain | first1=Prabin | last2=Jin | first2=Yue | last3=Tsilo | first3=Toi J. | last4=Macharia | first4=Godwin K. | last5=Reynolds | first5=Susan E. | last6=Wanyera | first6=Ruth | last7=Anderson | first7=James A. | title=Registration of KUWNSr, a wheat stem rust nested association mapping population | journal=Journal of Plant Registrations| volume=14 | issue=3 | date=2020-05-14 | issn=1936-5209 | doi=10.1002/plr2.20043 | pages=467–473 | s2cid=219423451}}
  }}
</ref> This resistance was present without the Ug99 pathogen challenge being present in NA to drive its selection.<ref name="Bajgain-et-al-2015-bundle" /> USDA has studied winter wheat land races where resistance is more probable.<ref name = "Action-Plan" >
 {{ Cite report |
       language=en|
             year=2007|
            pages=1–27|
              url=https://www.ars.usda.gov/ug99/actionplan.pdf |
            title=Action Plan to Minimize Impact of Ug99 Stem Rust in the United States|
           author=USDA [[Organization:Agricultural Research Service|Agricultural Research Service]]|
        publisher=USDA [[Organization:Agricultural Research Service|Agricultural Research Service]]|
          edition=1.01|
      archive-url=https://web.archive.org/web/20221020091749/http://www.ars.usda.gov/ug99/actionplan.pdf|
     archive-date=2022-10-20}}
</ref>

In addition to the research being conducted by the [[Organization:USDA|USDA]], The United Kingdom’s Department for International Development (DFID) along with Bill & Melinda Gates Foundation, announced in February 2011 that they will be granting $40 million to a global project led by [[Organization:Cornell University|Cornell University]] to combat virulent strains of Ug99.<ref name="CC40">{{ Cite news|url=https://news.cornell.edu/stories/2011/02/40m-grant-fight-wheat-rust-threatens-food-security|title=$40M grant to fight wheat pathogen that threatens global food security|work=Cornell Chronicle|language=en|access-date=October 5, 2019|first=Linda|last=McCandless|date=February 27, 2011}}</ref> The five-year grant to the Durable Rust Resistance in Wheat (DRRW) project supported attempts to identify new resistance genes as well as reproduce and distribute rust resistant wheat seeds to farmers.<ref name="CC40"/>

There has been a continuous process of development of new resistant cultivars and failure of those cultivars.<ref name="Wessels-et-al-2019-bundle" /> This demonstrates the need for continuous improvement.<ref name="Wessels-et-al-2019-bundle">
{{Unbulleted list citebundle
   |{{*}} {{ Cite journal | last1=Wessels | first1=Elsabet | last2=Prins | first2=Renée | last3=Boshoff | first3=Willem H. P. | last4=Zurn | first4=Jason D. | last5=Acevedo | first5=Maricelis | last6=Pretorius | first6=Zacharias A. | title=Mapping a Resistance Gene to ''Puccinia graminis'' f. sp. ''tritici'' in the Bread Wheat Cultivar 'Matlabas' | journal=Plant Disease | publisher=[[Organization:American Phytopathological Society|American Phytopathological Society]] | volume=103 | issue=9 | year=2019 | issn=0191-2917 | doi=10.1094/pdis-10-18-1731-re | pages=2337–2344| pmid=31306087 | doi-access=free | s2cid=146090970}}
    |{{*}} {{ Cite journal
              | language    = English
              | year        = 2021
              | publisher   = Taylor & Francis
              | volume      = 43
              | first4      = Ronald
              | first3      = Zacharias
              | first2      = Robert
              | first1      = Thomas
              | last4       = Depauw
              | last3       = Pretorius
              | last2       = Park
              | last1       = Fetch
              | issue       = sup2
              | pages       = S275–S297
              | s2cid       = 233672540
              | journal     = Canadian Journal of Plant Pathology
              | issn        = 0706-0661
              | doi         = 10.1080/07060661.2021.1902860
              | title       = Stem rust: its history in Kenya and research to combat a global wheat threat
           }}
      |{{*}} {{ Cite journal | last1=Pretorius | first1=Zacharias A. | last2=Prins | first2=Renée | last3=Wessels | first3=Elsabet | last4=Bender | first4=Cornel M. | last5=Visser | first5=Botma | last6=Boshoff | first6=Willem H.P. | title=Accomplishments in wheat rust research in South Africa | journal=South African Journal of Science | publisher=Academy of Science of South Africa | volume=116 | issue=11/12 | date=2020-11-26 | issn=1996-7489 | doi=10.17159/sajs.2020/7688 | pages=1–8 | s2cid=229382857}}
}}</ref>

{{As of|2020}} modern [[Biology:Molecular biology|molecular]] and [[Biology:Molecular genetics|molecular genetics]] techniques are identifying [[Philosophy:Quantitative trait locus|quantitative trait loci]] (QTLs), particular cellular structures, and individual [[Biology:R gene|R gene]]s more efficiently than ever before.<ref name="Deng-et-al-2020">{{cite journal | last1=Deng | first1=Yiwen | last2=Ning | first2=Yuese | last3=Yang | first3=Dong-Lei | last4=Zhai | first4=Keran | last5=Wang | first5=Guo-Liang | last6=He | first6=Zuhua | title=Molecular Basis of Disease Resistance and Perspectives on Breeding Strategies for Resistance Improvement in Crops | journal=Molecular Plant | publisher=Cell Press | volume=13 | issue=10 | date=2020-10-05 | issn=1674-2052 | pmid=32979566 | doi=10.1016/j.molp.2020.09.018 | pages=1402–1419| s2cid=221955936 }}</ref> These will be needed given the continuing severe, worldwide threat Ug99 poses.<ref name="Deng-et-al-2020" /><ref name=Singh11 />

''{{Vanchor|Sr35}}'' confers resistance to all other severe ''Pgt'' races and the original Ug99.<ref name="Variation"/> Salcedo ''et al.'', 2017 finds its ''Avr'' target, ''{{Vanchor|AvrSr35}}''.<ref name="Variation"/> Races virulent on ''Sr35'' benefit from nonfunctionalization of ''AvrSr35'' by insertion of a mobile element.<ref name="Variation">
:{{cite journal|issue=1|volume=10|year=2019|publisher=[[Company:Nature Portfolio|Nature Portfolio]]|last1=Li|first1=Feng|last2=Upadhyaya|first2=Narayana|last3=Sperschneider|first3=Jana|last4=Matny|first4=Oadi|last5=Nguyen-Phuc|first5=Hoa|last6=Mago|first6=Rohit|last7=Raley|first7=Castle|last8=Miller|first8=Marisa|last9=Silverstein|first9=Kevin|last10=Henningsen|first10=Eva|last11=Hirsch|first11=Cory|last12=Visser|first12=Botma|last13=Pretorius|first13=Zacharias|last14=Steffenson|first14=Brian|last15=Schwessinger|first15=Benjamin|last16=Dodds|first16=Peter|last17=Figueroa|first17=Melania|journal=Nature Communications|s2cid=207916981|bibcode=2019NatCo..10.5068L|pmid=31699975|pmc=6838127|doi=10.1038/s41467-019-12927-7|title=Emergence of the Ug99 lineage of the wheat stem rust pathogen through somatic hybridisation|page=5068|issn=2041-1723|id=(FL {{ORCID|0000-0001-8528-4249}}.) (NMU {{ORCID|0000-0002-3052-0416}}.) (OM {{ORCID|0000-0002-8447-2886}}.) (HNP {{ORCID|0000-0001-9329-4287}}.) (KATS {{ORCID|0000-0002-4955-3218}}.) (EH {{ORCID|0000-0001-9619-3705}}.) (CDH {{ORCID|0000-0002-3409-758X}}.) (BJS {{ORCID|0000-0001-7961-5363}}.) (PND {{ORCID|0000-0003-0620-5923}}. [[Google Scholar|GS]] [http://scholar.google.com/citations?user=N3w9QUUAAAAJ N3w9QUUAAAAJ]. [[ResearcherID|RID]] [http://researcherid.com/rid/D-1181-2009 D-1181-2009].) (MF {{ORCID|0000-0003-2636-661X}}. ([[ResearcherID|RID]] [http://researcherid.com/rid/R-7696-2017 R-7696-2017]) }}
:
:This review cites this research.
:
:{{cite journal|year=2017|publisher=American Association for the Advancement of Science (AAAS)|journal=Science|issn=0036-8075|last1=Salcedo|first1=Andres|last2=Rutter|first2=William|last3=Wang|first3=Shichen|last4=Akhunova|first4=Alina|last5=Bolus|first5=Stephen|last6=Chao|first6=Shiaoman|last7=Anderson|first7=Nickolas|last8=De Soto|first8=Monica|last9=Rouse|first9=Matthew|last10=Szabo|first10=Les|last11=Bowden|first11=Robert|last12=Dubcovsky|first12=Jorge|last13=Akhunov|first13=Eduard|pages=1604–1606|volume=358|issue=6370|s2cid=206664159|doi=10.1126/science.aao7294|title=Variation in the ''AvrSr35'' gene determines ''Sr35'' resistance against wheat stem rust race Ug99|pmid=29269474 |pmc=6518949 }}
</ref>

== Races ==
There are 15 races of Ug99, which (under the North American nomenclature system) have the designations TTKSK, TTKSF, TTKST, TTTSK, TTKSP, PTKSK, PTKST, TTKSF+,<ref name=Hodson12 /> TTKTT, TTKTK, TTHSK, PTKTK, TTHST, TTKTT+, and TTHTT.<ref name="Rust-Tracker"/> They are all closely related and are believed to have [[Biology:Evolution|evolved]] from a common ancestor.<ref name=Singh11 />

{{anchor|PTKS}}
=== TTKSK ===

Also known as '''PTKS'''.<ref name="Nagarajan-et-al-2012">{{ Cite journal | last1=Nagarajan | first1=Subrahmaniam | last2=Kogel | first2=Hans J. | last3=Zadoks | first3=Jan C. |  title=Epidemiology of ''Puccinia graminis'' f.sp. ''tritici''-Ug99 in the Rift Valley "Flyway" from Uganda-Kenya to Yemen | journal=Plant Health Progress | publisher=[[Organization:American Phytopathological Society|American Phytopathological Society]] | volume=13 | issue=1 | year=2012 | issn=1535-1025 | doi=10.1094/php-2012-1114-01-rv | page=31 | s2cid=88243732}}</ref> The first Ug99 race to be characterised.<ref name="Jin-et-al-2008-bundle" /><ref name="Nagarajan-et-al-2012" /> Like most Ug99 races, and unlike other stem rust varieties, it is virulent against the ''Sr'' gene ''Sr31'';<ref name="Jin-et-al-2008-bundle">
   {{Unbulleted list citebundle
      |{{*}} {{ Cite journal | last1=Jin | first1=Yue | last2=Szabo | first2=Les J. | last3=Pretorius | first3=Zacharias A. | last4=Singh | first4=Ravi P. | last5=Ward | first5=R. | last6=Fetch | first6=T. | title=Detection of Virulence to Resistance Gene ''Sr24'' Within Race TTKS of ''Puccinia graminis'' f. sp. ''tritici'' | journal=Plant Disease | publisher=[[Organization:American Phytopathological Society|American Phytopathological Society]] | volume=92 | issue=6 | year=2008 | issn=0191-2917 | doi=10.1094/pdis-92-6-0923 | pages=923–926| pmid=30769714 | doi-access=free | s2cid=55431333}}
         |{{*}} {{ Cite journal
 |   last1=Singh
 |  first1=Ravi P.
 |   last2=Hodson
 |  first2=David P.
 |   last3=Huerta-Espino
 |  first3=Julio
 |   last4=Jin
 |  first4=Yue
 |   last5=Bhavani
 |  first5=Sridhar
 |   last6=Njau
 |  first6=Peter
 |   last7=Herrera-Foessel
 |  first7=Sybil
 |   last8=Singh
 |  first8=Pawan K.
 |   last9=Singh
 |  first9=Sukhwinder
 |  last10=Govindan
 | first10=Velu
 | title=The Emergence of Ug99 Races of the Stem Rust Fungus is a Threat to World Wheat Production
 | journal=[[Biology:Annual Review of Phytopathology|Annual Review of Phytopathology]]
 | publisher=Annual Reviews
 | date=8 September 2011
 | volume=49
 | issue=1
 | pages=465–481
 | doi=10.1146/annurev-phyto-072910-095423
 | pmid=21568701
 | s2cid=24770327
 | issn=0066-4286
 }}
         | {{*}} {{ Cite book | last=Sparks | first=Donald L. | title=Advances in Agronomy | volume=98 | publication-place=[[Place:London|London]] | isbn=978-0-08-088814-9 | oclc=302357009 | pages=xiii+422 | issn=0065-2113 | publisher=[[Company:Elsevier|Elsevier]] | year=2008}} {{RP|page=281}}
         | {{*}} {{cite journal | last1=Singh | first1=Ravi P. | last2=Hodson | first2=David P. | last3=Jin | first3=Yue | last4=Lagudah | first4=Evans S. | last5=Ayliffe | first5=Michael A. | last6=Bhavani | first6=Sridhar | last7=Rouse | first7=Matthew N. | last8=Pretorius | first8=Zacharias A. | last9=Szabo | first9=Les J. | last10=Huerta-Espino | first10=Julio | last11=Basnet | first11=Bhoja R. | last12=Lan | first12=Caixia | last13=Hovmøller | first13=Mogens S. | title=Emergence and Spread of New Races of Wheat Stem Rust Fungus: Continued Threat to Food Security and Prospects of Genetic Control | journal=Phytopathology | publisher=[[Organization:American Phytopathological Society|American Phytopathological Society]] | volume=105 | issue=7 | year=2015 | issn=0031-949X | doi=10.1094/phyto-01-15-0030-fi | pages=872–884 | pmid=26120730 | s2cid=205345605}}
   }}
</ref><ref name="Nagarajan-et-al-2012" /> also virulent against ''Sr38''.<ref name="Nagarajan-et-al-2012" /> Avirulent against ''Sr24''.<ref name="Jin-et-al-2008-bundle" /><ref name="Nagarajan-et-al-2012" /> It was found in Uganda<ref name="Nagarajan-et-al-2012" /> in {{pslink||1999}}, Kenya<ref name="Jin-et-al-2008-bundle" /> in {{pslink||2001}},<ref name="Rust-Tracker" /> Ethiopia in {{pslink||2003}},<ref name="Rust-Tracker" /> Sudan and Yemen in {{pslink||2006}},<ref name="Rust-Tracker" /> [[Religion:Iran|Iran]] in {{pslink||2007}},<ref name="Rust-Tracker" /> and Tanzania<ref name=Singh11 /> in {{pslink||2009}},<ref name="Rust-Tracker" /> Eritrea in {{pslink||2012}},<ref name="Rust-Tracker" /> and [[Biology:Rwanda|Rwanda]] and [[Place:Egypt|Egypt]] in {{pslink||2014}}.<ref name="Rust-Tracker" />

=== TTKSF ===
First detected in South Africa in {{pslink||2000}},<ref name="Rust-Tracker" /> Zimbabwe {{pslink||2009}},<ref name="Rust-Tracker" /> and Uganda in {{pslink||2012}}.<ref name="Rust-Tracker" /> Avirulent on ''Sr31''.<ref name="Rust-Tracker" />

=== TTKST ===
Discovered in Kenya in {{pslink||2006}}<ref name="Jin-et-al-2008-bundle" /> was the first Ug99 race found to be virulent against ''Sr'' gene ''Sr24''.<ref name=Singh11 /><ref name="Jin-et-al-2008-bundle" /> TTKST is now the predominant stem rust race in Kenya.<ref name=Singh11 /> Virulent on ''Sr31''.<ref name="Rust-Tracker" />

=== TTTSK ===
First detected in Kenya in {{pslink||2007}},<ref name="Rust-Tracker" /> Tanzania in {{pslink||2009}},<ref name="Rust-Tracker" /> Ethiopia in {{pslink||2010}},<ref name="Rust-Tracker" /> Uganda in {{pslink||2012}},<ref name="Rust-Tracker" /> and Rwanda in {{pslink||2014}}.<ref name="Rust-Tracker" /> Virulent on ''Sr31'' and ''Sr36''.<ref name="Rust-Tracker" />

=== TTKSP ===
First detected by Visser ''et al.'', 2011 in South Africa in {{pslink||2007}}.<ref name = South-Africa /><ref name="Rust-Tracker" /> Avirulent on ''Sr31'' and virulent on ''Sr24''.<ref name="Rust-Tracker" />

=== PTKSK ===
First detected in Ethiopia in {{pslink||2007}},<ref name="Rust-Tracker" /> Kenya in {{pslink||2009}},<ref name="Rust-Tracker" /> Yemen in {{pslink||2009}},<ref name="Rust-Tracker" /> and South Africa in {{pslink||2017}}.<ref name="Rust-Tracker" /><ref name="Terefe-et-al-2019">{{cite journal | last1=Terefe | first1=T. | last2=Pretorius | first2=Z. A. | last3=Visser | first3=B. | last4=Boshoff | first4=W. H. P. | title=First Report of ''Puccinia graminis'' f. sp. ''tritici'' Race PTKSK, a Variant of Wheat Stem Rust Race Ug99, in South Africa | journal=Plant Disease | publisher=[[Organization:American Phytopathological Society|American Phytopathological Society]] | volume=103 | issue=6 | year=2019 | issn=0191-2917 | doi=10.1094/pdis-11-18-1911-pdn | pages=1421| doi-access=free }}</ref> Virulent on ''Sr31'' and avirulent on ''Sr21''.<ref name="Rust-Tracker" />

=== PTKST ===
First detected in Ethiopia in {{pslink||2007}},<ref name="Rust-Tracker" /> Kenya in {{pslink||2008}},<ref name="Rust-Tracker" /> South Africa in {{pslink||2009}} by Visser ''et al.'', 2011,<ref name = South-Africa /><ref name="Rust-Tracker" /> Eritrea and Mozambique and Zimbabwe in {{pslink||2010}}.<ref name="Rust-Tracker" /> Virulent on ''Sr31'' and ''Sr24'', but avirulent on ''Sr21''.<ref name="Rust-Tracker" />

=== TTKSF+ ===
First detected in both South Africa and Zimbabwe in {{pslink||2010}}.<ref name="Rust-Tracker" /> Virulent against ''Sr9h''.<ref name="Randhawa-et-al-2018">{{ Cite journal|publisher=Frontiers Media| last1=Randhawa | first1=Mandeep S. | last2=Singh | first2=Ravi P. | last3=Dreisigacker | first3=Susanne | last4=Bhavani | first4=Sridhar | last5=Huerta-Espino | first5=Julio | last6=Rouse | first6=Matthew N. | last7=Nirmala | first7=Jayaveeramuthu | last8=Sandoval-Sanchez | first8=Maricarmen | title=Identification and Validation of a Common Stem Rust Resistance Locus in Two Bi-parental Populations | journal=Frontiers in Plant Science| volume=9 | date=2018-11-30 | page=1788 | issn=1664-462X | doi=10.3389/fpls.2018.01788 | pmid=30555507 | pmc=6283910 | doi-access=free}}</ref><ref name="Pretorius-et-al-2012">{{ Cite journal | last1=Pretorius | first1=Z. A. | last2=Szabo | first2=Les J. | last3=Boshoff | first3=W. H. P. | last4=Herselman | first4=L. | last5=Visser | first5=B. | title=First Report of a New TTKSF Race of Wheat Stem Rust (''Puccinia graminis'' f. sp. ''tritici'') in South Africa and Zimbabwe | journal=Plant Disease | publisher=[[Organization:American Phytopathological Society|American Phytopathological Society]] | volume=96 | issue=4 | year=2012 | issn=0191-2917 | doi=10.1094/pdis-12-11-1027-pdn | pages=590| pmid=30727416 | doi-access=free}}</ref><ref name="Rouse-et-al-2014">{{ Cite journal|publisher=[[Company:Springer Science+Business Media|Springer Science+Business Media]]| last1=Rouse | first1=Matthew N. | last2=Nirmala | first2=Jayaveeramuthu | last3=Jin | first3=Yue | last4=Chao | first4=Shiaoman | last5=Fetch | first5=Thomas G. | last6=Pretorius | first6=Zacharias A. | last7=Hiebert | first7=Colin W. | title=Characterization of ''Sr9h'', a wheat stem rust resistance allele effective to Ug99|journal=Theoretical and Applied Genetics |volume=127 | issue=8 | date=2014-06-10 | issn=0040-5752 | doi=10.1007/s00122-014-2330-y | pages=1681–1688| pmid=24913360 | s2cid=2598581 }}</ref> Avirulent on ''Sr31'' but virulent on ''Sr9h''.<ref name="Rust-Tracker" />

=== TTKTT ===
First detected in Kenya in {{pslink||2014}}.<ref name="Rust-Tracker" /> Also detected in Iraq in 2019, the first such detection in the country.<ref name="Rust-Tracker" /> Virulent on ''Sr31'', ''Sr24'', and ''SrTmp''.<ref name="Rust-Tracker" />

=== TTKTK ===
First detected in Kenya,<ref name="Rust-Tracker" /><ref name="Patpour-et-al-2016-A-bundle">
{{Unbulleted list citebundle
   |{{*}} {{cite journal | last1=Patpour | first1=M. | last2=Hovmøller | first2=M. S. | last3=Justesen | first3=A. F. | last4=Newcomb | first4=M. | last5=Olivera | first5=P. | last6=Jin | first6=Y. | last7=Szabo | first7=Les J. | last8=Hodson | first8=D. | last9=Shahin | first9=A. A. | last10=Wanyera | first10=R. | last11=Habarurema | first11=I. | last12=Wobibi | first12=S. | title=Emergence of Virulence to ''SrTmp'' in the Ug99 Race Group of Wheat Stem Rust, ''Puccinia graminis'' f. sp. ''tritici'', in Africa | journal=Plant Disease | publisher=[[Organization:American Phytopathological Society|American Phytopathological Society]] | volume=100 | issue=2 | year=2016 | issn=0191-2917 | doi=10.1094/pdis-06-15-0668-pdn | pages=522 | doi-access=free | s2cid=83728264}}
      |{{*}} {{ Cite journal | last1=Prasad | first1=Pramod | last2=Savadi | first2=Siddanna | last3=Bhardwaj | first3=S. C. | last4=Gangwar | first4=O. P. | last5=Kumar | first5=Subodh | title=Rust pathogen effectors: perspectives in resistance breeding | journal=Planta | publisher=[[Company:Springer Science+Business Media|Springer Science+Business Media]] | volume=250 | issue=1 | date=2019-04-12 | issn=0032-0935 | doi=10.1007/s00425-019-03167-6 | pages=1–22 | s2cid=111390872 | pmid=30980247}}
      |{{*}} {{ Cite book | last1=Kang | first1=Zhensheng | last2=Chen | first2=Xianming | title=Stripe rust | publication-place=Dordrecht | isbn=978-94-024-1111-9 | oclc=1006649931 | pages=vii+719 | publisher=Springer Netherlands | s2cid=30527470 | doi=10.1007/978-94-024-1111-9 | date=2017}} {{isbn|978-94-024-1491-2}}. {{isbn|978-94-024-1109-6}}. Page 609.
      |{{*}} {{ Cite journal | last1=Figueroa | first1=Melania | last2=Upadhyaya | first2=Narayana M. | last3=Sperschneider | first3=Jana | last4=Park | first4=Robert F. | last5=Szabo | first5=Les J. | last6=Steffenson | first6=Brian | last7=Ellis | first7=Jeff G. | last8=Dodds | first8=Peter N. | title=Changing the Game: Using Integrative Genomics to Probe Virulence Mechanisms of the Stem Rust Pathogen ''Puccinia graminis'' f. sp. ''tritici'' | journal=Frontiers in Plant Science | publisher=Frontiers Media | volume=7 | date=2016-02-24 | page=205 | issn=1664-462X | doi=10.3389/fpls.2016.00205 | s2cid=12619852 | pmid=26941766 | pmc=4764693| doi-access=free }}
}}</ref> Rwanda,<ref name="Rust-Tracker" /><ref name="Patpour-et-al-2016-A-bundle" /> Uganda,<ref name="Rust-Tracker" /><ref name="Patpour-et-al-2016-A-bundle" /> Eritrea,<ref name="Rust-Tracker" /> and Egypt<ref name="Rust-Tracker" /><ref name="Patpour-et-al-2016-A-bundle" /> in {{pslink||2014}}. Virulent on ''Sr31'' and ''SrTmp''.<ref name="Rust-Tracker" />

=== TTHSK ===
First detected in Kenya in {{pslink||2014}}.<ref name="Fetch-et-al-2016-bundle" /> Differs from the original (TTKSK) by avirulence against ''Sr30''.<ref name="Fetch-et-al-2016-bundle" /> Similar to TTHST.<ref name="Fetch-et-al-2016-bundle" /> Virulent on ''Sr31'' but avirulent on ''Sr30''.<ref name="Rust-Tracker" />

=== PTKTK ===
First detected in Kenya in {{pslink||2014}}.<ref name="Fetch-et-al-2016-bundle" /> Differs from PTKSK by virulence against ''SrTmp''.<ref name="Fetch-et-al-2016-bundle" /> Differs from TTKTK by avirulence against ''Sr21''.<ref name="Fetch-et-al-2016-bundle" /> Virulent on ''Sr31'' and ''Sr24'', but avirulent on ''Sr21''.<ref name="Rust-Tracker" />

=== TTHST ===
First detected in Kenya in {{pslink||2013}}.<ref name="Rust-Tracker" /> Virulent on ''Sr31'' and ''Sr24'', but avirulent on ''Sr30''.<ref name="Rust-Tracker" />

=== TTKTT+ ===
First detected in Kenya in {{pslink||2019}}.<ref name="Rust-Tracker" /> Virulent to ''Sr31'', ''Sr24'', ''SrTmp'', and ''Sr8155B1''.<ref name="Rust-Tracker" />

=== TTHTT ===
First detected in Kenya in {{pslink||2020}}.<ref name="Rust-Tracker" /> Virulent to ''Sr31'', ''Sr24'', and ''SrTmp'', avirulent to ''Sr30''.<ref name="Rust-Tracker" />

== Timeline ==
=== 1993 ===
* There is some evidence that race TTKSK may have been present in Kenya.<ref name="Singh08">{{Cite journal|publisher=Elsevier B. V.|last1=Singh|first1=Ravi P.|last2=Hodson|first2=David|last3=Huerta-Espino|first3=Julio|last4=Jin|first4=Yue|last5=Njau|first5=Peter|last6=Wanyera|first6=Ruth|last7=Herrera-Foessel|first7=Sybil|last8=Ward|first8=Richard W.|year=2008|title=Will Stem Rust Destroy The World's Wheat Crop?|url=https://naldc-legacy.nal.usda.gov/naldc/download.xhtml?id=36520&content=PDF|journal=Advances in Agronomy|volume=98|pages=272–309|doi=10.1016/S0065-2113(08)00205-8|isbn=9780123743558|access-date=2018-12-29|archive-date=2020-11-08|archive-url=https://web.archive.org/web/20201108063602/https://naldc-legacy.nal.usda.gov/naldc/download.xhtml?id=36520&content=PDF|url-status=dead}}</ref>
=== 1998 ===
* Severe stem rust infections observed in Uganda. Ug99 identified, characterised as having virulence on ''Sr31'' and named.<ref name=Singh08 />
=== 2000 ===
* TTKSF detected in {{wipe|South Africa}}.<ref name=Singh11 />
=== 2001 ===
* TTKSK detected in Kenya.<ref name=Singh11 />
=== 2003 ===
* TTKSK detected in Ethiopia.<ref name=Singh11 />
=== 2006 ===
* TTKSK detected in Sudan and Yemen.<ref name=Singh08 />
* TTKST, a new variant of Ug99 with virulence to ''Sr24'', detected in Kenya.<ref name=Singh08 />
=== 2007 ===
* TTTSK detected in Kenya.<ref name=Singh11 />
* TTKSP detected in {{wipe|South Africa}} by Visser ''et al.'', 2011.<ref name = South-Africa />
* PTKSK detected in Ethiopia.<ref name=Singh11 />
* PTKST detected in Ethiopia.<ref name=Singh11 />
=== 2008 ===
* FAO announced the presence of Ug99 in [[Religion:Iran|Iran]].<ref name="Singh11">
 {{ Cite journal
 |   last1=Singh
 |  first1=Ravi P.
 |   last2=Hodson
 |  first2=David P.
 |   last3=Huerta-Espino
 |  first3=Julio
 |   last4=Jin
 |  first4=Yue
 |   last5=Bhavani
 |  first5=Sridhar
 |   last6=Njau
 |  first6=Peter
 |   last7=Herrera-Foessel
 |  first7=Sybil
 |   last8=Singh
 |  first8=Pawan K.
 |   last9=Singh
 |  first9=Sukhwinder
 |  last10=Govindan
 | first10=Velu
 | title=The Emergence of Ug99 Races of the Stem Rust Fungus is a Threat to World Wheat Production
 | journal=[[Biology:Annual Review of Phytopathology|Annual Review of Phytopathology]]
 | publisher=Annual Reviews
 | date=8 September 2011
 | volume=49
 | issue=1
 | pages=465–481
 | doi=10.1146/annurev-phyto-072910-095423
 | pmid=21568701
 | s2cid=24770327
 | issn=0066-4286
 }}
</ref><ref name="Gross-2013" />
* PTKST detected in Kenya.<ref name=Singh11 />
* Present in Yemen.<ref name="Gross-2013" />
=== 2009 ===
* TTKSK detected in Tanzania.<ref name=Singh11 />
* TTKST detected in Tanzania.<ref name=Singh11 />
* TTTSK detected in Tanzania.<ref name=Singh11 />
* TTKSF detected in Zimbabwe.<ref name=Singh11 />
* PTKSK detected in Kenya.<ref name=Singh11 />
* PTKST detected in {{wipe|South Africa}} by Visser ''et al.'', 2011.<ref name = South-Africa >
This review...
{{ Cite journal
 |   last1=Singh
 |  first1=Ravi P.
 |   last2=Hodson
 |  first2=David P.
 |   last3=Huerta-Espino
 |  first3=Julio
 |   last4=Jin
 |  first4=Yue
 |   last5=Bhavani
 |  first5=Sridhar
 |   last6=Njau
 |  first6=Peter
 |   last7=Herrera-Foessel
 |  first7=Sybil
 |   last8=Singh
 |  first8=Pawan K.
 |   last9=Singh
 |  first9=Sukhwinder
 |  last10=Govindan
 | first10=Velu
 | title= The Emergence of Ug99 Races of the Stem Rust Fungus is a Threat to World Wheat Production
 | journal=[[Biology:Annual Review of Phytopathology|Annual Review of Phytopathology]]
 | publisher=Annual Reviews
 | date=8 September 2011
 | volume=49
 | issue=1
 | pages=465–481
 | doi=10.1146/annurev-phyto-072910-095423
 | pmid=21568701
 | s2cid=24770327
 | issn=0066-4286
 }}

...cites this study:

{{ Cite journal | last1 = Visser | first1 = B | last2 = Herselman | first2 = L | last3 = Park | first3 = RF | last4 = Karaoglu | first4 = H | last5 = Bender | first5 = CM | last6 = Pretorius | first6 = Z | year = 2010 | title= Characterization of two new ''Puccinia graminis'' f. sp. ''tritici'' races within the Ug99 lineage in South Africa | journal=Euphytica | volume = 179 | pages = 119–127 | doi = 10.1007/s10681-010-0269-x | s2cid = 6176783 }}
</ref>
=== 2010 ===
* TTKST detected in Eritrea.<ref name=Hodson12 />
* PTKST detected in Eritrea.<ref name=Hodson12 />
* PTKST detected in Mozambique.<ref name=Hodson12 />
* PTKST detected in Zimbabwe.<ref name=Hodson12 />
* TTKSF+ detected in {{wipe|South Africa}}.<ref name=Hodson12 />
* TTKSF+ detected in Zimbabwe.<ref name=Hodson12 />
=== 2013 ===
* TTHST confirmed in Kenya<ref name="Rust-Tracker"/>
=== 2014 ===
* TTKTK confirmed in [[Place:Egypt|Egypt]],<ref name="Patpour-et-al-2016-B-bundle">
{{ Unbulleted list citebundle
   |{{*}} {{cite journal | last1=Patpour | first1=M. | last2=Hovmøller | first2=M. S. | last3=Shahin | first3=A. A. | last4=Newcomb | first4=M. | last5=Olivera | first5=P. | last6=Jin | first6=Y. | last7=Luster | first7=D. | last8=Hodson | first8=D. | last9=Nazari | first9=K. | last10=Azab | first10=M. | title=First Report of the Ug99 Race Group of Wheat Stem Rust, ''Puccinia graminis'' f. sp. ''tritici'', in Egypt in 2014 | journal=Plant Disease | publisher=[[Organization:American Phytopathological Society|American Phytopathological Society]] | volume=100 | issue=4 | year=2016 | issn=0191-2917 | doi=10.1094/pdis-08-15-0938-pdn | pages=863 | doi-access=free }}
   |{{*}} This study is cited by the following reviews & books:
      |{{*}} {{cite journal | last1=Prasad | first1=Pramod | last2=Savadi | first2=Siddanna | last3=Bhardwaj | first3=S. C. | last4=Gangwar | first4=O. P. | last5=Kumar | first5=Subodh | title=Rust pathogen effectors: perspectives in resistance breeding | journal=Planta | publisher=[[Company:Springer Science+Business Media|Springer Science+Business Media]] | volume=250 | issue=1 | date=2019-04-12 | issn=0032-0935 | doi=10.1007/s00425-019-03167-6 | pages=1–22 | s2cid=111390872 | pmid=30980247}}
      |{{*}} {{ Cite journal|last1=Bhavani|first1=Sridhar|last2=Hodson|first2=David P.|last3=Huerta-Espino|first3=Julio|last4=Randhawa|first4=Mandeep S.|last5=Singh|first5=Ravi P.|title=Progress in breeding for resistance to Ug99 and other races of the stem rust fungus in CIMMYT wheat germplasm|journal=Frontiers of Agricultural Science and Engineering|publisher=Engineering Sciences Press|volume=6|issue=3|year=2019|issn=2095-7505|doi=10.15302/j-fase-2019268|page=210|s2cid=202011907}}
      |{{*}} {{cite journal|publisher=[[Company:Elsevier|Elsevier]]| last1=Abdelmageed | first1=Kishk | last2=CHANG | first2=Xu-hong | last3=WANG | first3=De-mei | last4=WANG | first4=Yan-jie | last5=YANG | first5=Yu-shuang | last6=ZHAO | first6=Guang-cai | last7=TAO | first7=Zhi-qiang | title=Evolution of varieties and development of production technology in Egypt wheat: A review | journal=Journal of Integrative Agriculture | volume=18 | issue=3 | year=2019 | issn=2095-3119 | doi=10.1016/s2095-3119(18)62053-2 | pages=483–495 | s2cid=92749147}}
      |{{*}} {{cite book | last1=Awaad | first1=Hassan Auda | last2=El-Naggar | first2=Doaa Ragheb | series=Springer Water | title=Mitigating Environmental Stresses for Agricultural Sustainability in Egypt | chapter=Developing Rust Resistance of Wheat Genotypes Under Egyptian Conditions | publisher=Springer International Publishing | publication-place=Cham, Switzerland | year=2021 | isbn=978-3-030-64322-5 | issn=2364-6934 | doi=10.1007/978-3-030-64323-2_12 | pages=311–370| s2cid=234309678 }} Page 327.
}}
</ref> Kenya, Eritrea, [[Biology:Rwanda|Rwanda]], and Uganda.<ref name="Rust-Tracker"/>
* TTHSK confirmed in Kenya<ref name="Rust-Tracker"/><ref name="Fetch-et-al-2016-bundle">
{{Unbulleted list citebundle
   |{{*}} {{cite journal | last1=Fetch | first1=T. | last2=Zegeye | first2=T. | last3=Park | first3=R. F. | last4=Hodson | first4=D. | last5=Wanyera | first5=R. | title=Detection of Wheat Stem Rust Races TTHSK and PTKTK in the Ug99 Race Group in Kenya in 2014 | journal=Plant Disease | publisher=[[Organization:American Phytopathological Society|American Phytopathological Society]] | volume=100 | issue=7 | year=2016 | issn=0191-2917 | doi=10.1094/pdis-11-15-1356-pdn | pages=1495 | doi-access=free | s2cid=87136095}}
   |{{*}} This study is cited by the following reviews & books:
      |{{*}} {{cite journal | last1=Prasad | first1=Pramod | last2=Savadi | first2=Siddanna | last3=Bhardwaj | first3=S. C. | last4=Gangwar | first4=O. P. | last5=Kumar | first5=Subodh | title=Rust pathogen effectors: perspectives in resistance breeding | journal=Planta | publisher=[[Company:Springer Science+Business Media|Springer Science+Business Media]] | volume=250 | issue=1 | date=2019-04-12 | issn=0032-0935 | doi=10.1007/s00425-019-03167-6 | pages=1–22 | s2cid=111390872 | pmid=30980247}}
      |{{*}} {{cite journal | last1=Bhavani | first1=Sridhar | last2=Hodson | first2=David P. | last3=Huerta-Espino | first3=Julio | last4=Randhawa | first4=Mandeep S. | last5=Singh | first5=Ravi P. | title=Progress in breeding for resistance to Ug99 and other races of the stem rust fungus in CIMMYT wheat germplasm | journal=Frontiers of Agricultural Science and Engineering | publisher=Engineering Sciences Press | volume=6 | issue=3 | year=2019 | issn=2095-7505 | doi=10.15302/j-fase-2019268 | page=210 | s2cid=202011907}}
      |{{*}} {{cite book | last1=Awaad | first1=Hassan Auda | last2=El-Naggar | first2=Doaa Ragheb | series=Springer Water | title=Mitigating Environmental Stresses for Agricultural Sustainability in Egypt | chapter=Developing Rust Resistance of Wheat Genotypes Under Egyptian Conditions | publisher=Springer International Publishing | publication-place=Cham, Switzerland | year=2021 | isbn=978-3-030-64322-5 | issn=2364-6934 | doi=10.1007/978-3-030-64323-2_12 | pages=311–370| s2cid=234309678 }} Page 327.
      |{{*}} {{cite journal | last1=Kenis | first1=Marc | last2=Agboyi | first2=Lakpo Koku | last3=Adu-Acheampong | first3=Richard | last4=Ansong | first4=Michael | last5=Arthur | first5=Stephen | last6=Attipoe | first6=Prudence Tonator | last7=Baba | first7=Abdul-Salam Mahamud | last8=Beseh | first8=Patrick | last9=Clottey | first9=Victor Attuquaye | last10=Combey | first10=Rofela | last11=Dzomeku | first11=Israel | last12=Eddy-Doh | first12=Mary Akpe | last13=Fening | first13=Ken Okwae | last14=Frimpong-Anin | first14=Kofi | last15=Hevi | first15=Walter | last16=Lekete-Lawson | first16=Emmanuellah | last17=Nboyine | first17=Jerry Asalma | last18=Ohene-Mensah | first18=Godfried | last19=Oppong-Mensah | first19=Birgitta | last20=Nuamah | first20=Hannah Serwaa Akoto | last21=van der Puije | first21=Grace | last22=Mulema | first22=Joseph | title=Horizon scanning for prioritising invasive alien species with potential to threaten agriculture and biodiversity in Ghana | journal=NeoBiota | publisher=[[Company:Pensoft Publishers|Pensoft Publishers]] | volume=71 | date=2022-02-08 | issn=1314-2488 | doi=10.3897/neobiota.71.72577 | pages=129–148 | s2cid=246821009 | doi-access=free }}
      |{{*}} {{cite journal | last1=Fetch | first1=Thomas G. | last2=Park | first2=Robert F. | last3=Pretorius | first3=Zacharias A. | last4=Depauw | first4=Ronald M. | title=Stem rust: its history in Kenya and research to combat a global wheat threat | journal=Canadian Journal of Plant Pathology | publisher=[[Organization:Agriculture and Agri-Food Canada|Agriculture and Agri-Food Canada]] (T&F) | volume=43 | issue=sup2 | date=2021-09-27 | issn=0706-0661 | doi=10.1080/07060661.2021.1902860 | pages=S275–S297 | s2cid=233672540}}
}}
</ref>
* PTKTK confirmed in Kenya<ref name="Rust-Tracker"/><ref name="Fetch-et-al-2016-bundle" />
* TTKTT confirmed in Kenya.<ref name="Fetch-et-al-2016-bundle" />
* TTKST detected in Egypt.<ref name="Patpour-et-al-2016-B-bundle" />
* TTKSK detected in Egypt.<ref name="Patpour-et-al-2016-B-bundle" />
=== 2017 ===
* PTKSK confirmed in South Africa.<ref name="Rust-Tracker" />
=== 2019 ===
* TTKTT detected in Iraq.<ref name="Rust-Tracker" />
* TTKTT+ confirmed in Kenya.<ref name="Rust-Tracker" />
=== 2020 ===
* TTHTT confirmed in Kenya.<ref name="Rust-Tracker" />

== Geographic spread ==
Because stem rust (as with many fungi) spreads its [[Biology:Spore|spore]]s across long distances with the help of natural [[Earth:Air current|air current]]s, containment is difficult.<ref name = "Highways-Sky" /> Advances in [[Physics:Fluid mechanics|fluid mechanics]] which are commonly used for [[Physics:Meteorology|meteorology]] have also aided Ug99 dispersal prediction.<ref name = "Highways-Sky" /> This is especially important for inter-continental, intermittent spread, such as from Eastern {{wipe|South Africa}} to Western Australia.<ref name = "Highways-Sky" >
 {{ Cite journal |
       language=en|
           year=2015|
          issue=1|
         volume=53|
      publisher=Annual Reviews|
         first2=Shane|
         first1=David|
          last2=Ross|
          pages=591–611|
          last1=Schmale|
        journal=[[Biology:Annual Review of Phytopathology|Annual Review of Phytopathology]]|
          title=Highways in the Sky: Scales of Atmospheric Transport of Plant Pathogens|
            doi=10.1146/annurev-phyto-080614-115942|
           pmid=26047561}}
</ref>

=== China ===
Although '''Ug99''' has not yet reached {{wipe|China}},<ref name="Wu-et-al-2020">{{cite journal | last1=Wu | first1=Xian Xin | last2=Lin | first2=Qiu Jun | last3=Ni | first3=Xin Yu | last4=Sun | first4=Qian | last5=Chen | first5=Rong Zhen | last6=Xu | first6=Xiao Feng | last7=Qiu | first7=Yong Chun | last8=Li | first8=Tian Ya | title=Characterization of Wheat Monogenic Lines with Known ''Sr'' Genes and Wheat Lines with Resistance to the Ug99 Race Group for Resistance to Prevalent Races of ''Puccinia graminis'' f. sp. ''tritici'' in China | journal=Plant Disease | publisher=[[Organization:American Phytopathological Society|American Phytopathological Society]] | volume=104 | issue=7 | year=2020 | issn=0191-2917 | doi=10.1094/pdis-12-19-2736-re | pages=1939–1943| pmid=32396054 | doi-access=free }}</ref> other stem rust races already have,<ref name="Wu-et-al-2020" /> and an effort is under way to marry resistance against present races with future needs for resistance against '''Ug99''' whenever it arrives.<ref name="Wu-et-al-2020" />

=== Lebanon ===
Although ''Sr5'', ''Sr21'', ''Sr9e'', ''Sr7b'', ''Sr11'', ''Sr6'', ''Sr8a'', ''Sr9g'', ''Sr9b'', ''Sr30'', ''Sr17'', ''Sr9a'', ''Sr9d'', ''Sr10'', ''SrTmp'', ''Sr38'', and ''SrMcN'' are no longer effective in [[Place:Lebanon|Lebanon]], ''Sr11'', ''Sr24'', and ''Sr31'' still are which is diagnostic for the absence of Ug99 from Lebanon.<ref name="IITA-CGIAR-slide-Yr-Sr">{{Cite AV media|url=http://youtube.com/watch?v=9ksaCvAy_XQ&t=2677 |archive-url=https://ghostarchive.org/varchive/youtube/20211215/9ksaCvAy_XQ |archive-date=2021-12-15 |url-status=live|publisher=[[Organization:International Institute of Tropical Agriculture|International Institute of Tropical Agriculture]] + [[Organization:CGIAR|CGIAR]] |series=CGIAR Germplasm Health Webinar series|volume=Phytosanitary Awareness Week |title=(DAY 2) - Phytosanitary Safety for Transboundary pest prevention - Yellow and Black rust population variability|date=2020-11-09|time-caption=Slide at|time=00:44:37|editor-first1=Rola | editor-last1=El Amil | last=Kumari | first=Safaa | }}{{cbignore}}<!--- Sr36 intentionally left out because it is in both lists in the cited slide which can't be correct. User:Invasive Spices ---></ref>

=== Iraq ===
Detected in Iraq in 2019.<ref name="Rust-Tracker" />

=== South Asia ===
{{As of|2013}} it was the US Director of National Intelligence's assessment that Ug99 would arrive in [[Place:South Asia|South Asia]] soon, in the following few years. This was expected to cause worldwide supply disruptions because, although productivity was growing in [[Place:Eastern Europe|Eastern Europe]] and could theoretically fill that gap, governments worldwide had shown a readiness to forbid exports.<ref name="Ug99-US-DNI">{{cite web | url=http://www.dni.gov/files/documents/Intelligence%20Reports/2013%20ATA%20SFR%20for%20SSCI%2012%20Mar%202013.pdf | title=Statement for the Record | publisher=Senate Select Committee on Intelligence | first=James | last=Clapper |  date=March 12, 2013 | website=Director of National Intelligence}}</ref> However {{as of|April 2021|lc=yes}} South Asia remains unaffected.<ref name="Rust-Tracker" />

== See also ==
* [[Biology:Stem rust|Stem rust]]
* [[Biology:Rust (fungus)|Rust (fungus)]]

== References ==
{{Reflist}}

== External links ==
* [http://www.youtube.com/watch?v=qsH9KkNd3Uk&list=PLJZDl3j4wcgL4KcP-fmsoAI7CqmR8fb3O&index=5&t=0s Ug99 stem rust on wheat crops]
* [http://bgri.cornell.edu Borlaug Global Rust Initiative]
* [http://www.fao.org/agriculture/crops/rust/stem/rust-report/stem-ug99racettksk/en/ FAO]

{{Taxonbar|from= Q7877558}}








[[Category:Puccinia]]

{{Sourceattribution|Ug99}}