View source for Biology:Aureobasidium pullulans

{{Short description|Species of fungus}}
{{Speciesbox
| image = Aureobasidium pullulans 44026.jpg
| genus = Aureobasidium
| species = pullulans
| authority = (de Bary) G. Arnaud (1918)
| synonyms =
''Aureobasidium oleae'' <small></small><br>
''Aureobasidium pullulans'' <small></small><br>
''Azymocandida malicola'' <small></small><br>
''Candida malicola'' <small></small><br>
''Cladosporium pullulans'' <small></small><br>
''Dematium pullulans'' <small></small><br>
''Exobasidium vitis'' <small></small><br>
''Hormonema oleae'' <small></small><br>
''Hormonema pullulans'' <small></small><br>
''Pullularia fermentans'' <small></small><br>
''Pullularia fermentans var. schoenii'' <small></small><br>
''Pullularia pullulans'' <small></small><br>
''Torula oleae'' <small></small><br>
''Torula schoenii'' <small></small>
}}

'''''Aureobasidium pullulans''''' is a ubiquitous and generalistic [[Biology:Black yeast|black, yeast-like fungus]] that can be found in different environments (e.g. soil, water, air and limestone). It is well known as a naturally occurring [[Earth:Epiphyte|epiphyte]] or [[Biology:Endophyte|endophyte]] of a wide range of plant species (e.g. [[Biology:Apple|apple]], grape, cucumber, green beans, cabbage) without causing any symptoms of disease.<ref>{{Cite journal
 | pmid = 12166677
| year = 2002
| last1 = Andrews
| first1 = J. H.
| title = Population biology of Aureobasidium pullulans on apple leaf surfaces
| journal = Canadian Journal of Microbiology
| volume = 48
| issue = 6
| pages = 500–13
| last2 = Spear
| first2 = R. N.
| last3 = Nordheim
| first3 = E. V.
 | doi=10.1139/w02-044
}}</ref> ''A. pullulans'' has a high importance in [[Engineering:Biotechnology|biotechnology]] for the production of different enzymes, siderophores and [[Chemistry:Pullulan|pullulan]].<ref>{{Cite journal
 | pmid = 19198830
| year = 2009
| last1 = Chi
| first1 = Z
| title = Bioproducts from Aureobasidium pullulans, a biotechnologically important yeast
| journal = Applied Microbiology and Biotechnology
| volume = 82
| issue = 5
| pages = 793–804
| last2 = Wang
| first2 = F
| last3 = Chi
| first3 = Z
| last4 = Yue
| first4 = L
| last5 = Liu
| first5 = G
| last6 = Zhang
| first6 = T
| doi = 10.1007/s00253-009-1882-2
| s2cid = 6356992
}}</ref> Furthermore, ''A. pullulans'' is used in biological control of plant diseases, especially storage diseases.<ref>{{Cite journal
 | pmid = 17390846
| year = 2006
| last1 = Ferreira-Pinto
| first1 = M. M.
| title = Aureobasidium pullulansas a biocontrol agent of blue mold in "Rocha" pear
| journal = Communications in Agricultural and Applied Biological Sciences
| volume = 71
| issue = 3 Pt B
| pages = 973–8
| last2 = Moura-Guedes
| first2 = M. C.
| last3 = Barreiro
| first3 = M. G.
| last4 = Pais
| first4 = I
| last5 = Santos
| first5 = M. R.
| last6 = Silva
| first6 = M. J.
}}</ref><ref>{{Cite journal
 | pmid = 22225984
| year = 2012
| last1 = Zhang
| first1 = D
| title = Cloning, characterization, expression and antifungal activity of an alkaline serine protease of Aureobasidium pullulans PL5 involved in the biological control of postharvest pathogens
| journal = International Journal of Food Microbiology
| volume = 153
| issue = 3
| pages = 453–64
| last2 = Spadaro
| first2 = D
| last3 = Valente
| first3 = S
| last4 = Garibaldi
| first4 = A
| last5 = Gullino
| first5 = M. L.
| doi = 10.1016/j.ijfoodmicro.2011.12.016
| hdl = 2318/88995
| s2cid = 42311632
| hdl-access = free
}}</ref>

Chronic human exposure to ''A. pullulans'' via humidifiers or air conditioners can lead to hypersensitivity [[Medicine:Pneumonitis|pneumonitis]] (extrinsic allergic alveolitis) or "humidifier lung".  This condition is characterized acutely by dyspnea, cough, fever, chest infiltrates, and acute inflammatory reaction.  The condition can also be chronic, and [[Biology:Lymphocyte|lymphocyte]]-mediated. The chronic condition is characterized radiographically by reticulonodular infiltrates in the lung, with apical sparing. The strains causing infections in humans were reclassified to ''[[Biology:Aureobasidium melanogenum|A. melanogenum]]''.<ref name="Aureobasidium spp. genomes" />

''A. pullulans'' can be cultivated on [[Biology:Potato|potato]] dextrose [[Biology:Agar|agar]], where it produces smooth, faint pink, yeast-like colonies covered with a slimy mass of spores. Older colonies change to black due to [[Biology:Chlamydospore|chlamydospore]] production. Primary [[Biology:Conidium|conidia]] are [[Biology:Hyaline|hyaline]], smooth, ellipsoidal, one-celled, and variable in shape and size; secondary conidia are smaller. [[Biology:Conidium|Conidiophores]] are undifferentiated, intercalary or terminal, or arising as short lateral branches. [[Biology:Endoconidium|Endoconidia]] are produced in an intercalary cell and released into a neighboring empty cell. [[Biology:Hypha|Hypha]]e are hyaline, smooth, and thinwalled, with transverse [[Biology:Septum|septa]]. The fungus grows at 10–35&nbsp;°C with optimum growth at 30&nbsp;°C.{{cn|date=November 2022}}

''A. pullulans'' is notable for its [[Biology:Phenotypic plasticity|phenotypic plasticity]]. Colony [[Biology:Morphology|morphology]] may be affected by [[Chemistry:Organic compound|carbon source]], colony age, temperature, light and [[Biology:Substrate|substrate]], with colonies ranging from homogeneous to sectored, yeast-like to filamentous growth, and from small to large.<ref name="plasticity">{{Cite journal
 | pmid = 19927747
| year = 2009
| last1 = Slepecky
| first1 = R. A.
| title = Phenotypic plasticity in fungi: A review with observations on Aureobasidium pullulans
| journal = Mycologia
| volume = 101
| issue = 6
| pages = 823–32
| last2 = Starmer
| first2 = W. T.
 | doi=10.3852/08-197
| s2cid = 24313971
}}</ref> These changes, potentially influenced by epigenetic factors, and the particular developmental sequences that the colonies proceed through may be observed with the [[Astronomy:Naked eye|naked eye]].<ref name="plasticity" /> Besides these [[Biology:Morphology|morphological]] plasticity ''A. pullulans'' is also adaptable to various [[Medicine:Stress|stressful]] conditions: hypersaline, acidic and alkaline, cold, and oligotrophic. Therefore, it is considered to be polyextremotolerant.<ref>{{cite journal | last1 = Gostinčar | first1 = C. | last2 = Grube | first2 = M. | last3 = Gunde-Cimerman | first3 = N. | year = 2011 | title = Evolution of Fungal Pathogens in Domestic Environments? | journal = Fungal Biol. | volume = 115 | issue = 10| pages = 1008–1018 | pmid = 21944213 | doi=10.1016/j.funbio.2011.03.004}}</ref>

The morphology-based taxonomy of the species is complicated by the large morphological variability between strains and even within a single strain. Based on molecular analyses, four varieties of the species ''A. pullulans'' were recognised: var. ''pullulans'' from substrates with low water activity and the [[Biology:Phyllosphere|phyllosphere]] and a variety of other habitats; var. ''melanogenum ''from aquatic habitats; var. ''subglaciale'' from glacial habitats; and var. ''namibiae'', which was described on the basis of only one strain isolated from dolomitic [[Chemistry:Marble|marble]] in Namibia.<ref>{{Cite journal
| last1 = Zalar | first1 = P.
| last2 = Gostincar | first2 = C.
| last3 = De Hoog | first3 = G. S.
| last4 = Ursic | first4 = V.
| last5 = Sudhadham | first5 = M.
| last6 = Gunde-Cimerman | first6 = N.
| doi = 10.3114/sim.2008.61.02
| title = Redefinition of Aureobasidium pullulans and its varieties
| journal = Studies in Mycology
| volume = 61
| pages = 21–38
| year = 2008
| pmid = 19287524
| pmc =2610310
}}</ref> However, when the genome sequences of these varieties became available, the differences between them were considered as too large to be accommodated in a single species. Therefore, the varieties were reclassified as new species: ''A. pullulans'', ''[[Biology:Aureobasidium melanogenum|A. melanogenum]]'', ''[[Biology:Aureobasidium subglaciale|A. subglaciale]]'', and ''[[Biology:Aureobasidium namibiae|A. namibiae]]''.<ref name="Aureobasidium spp. genomes">{{cite journal|last1=Gostinčar|first1=Cene|last2=Ohm|first2=Robin A|last3=Kogej|first3=Tina|last4=Sonjak|first4=Silva|last5=Turk|first5=Martina|last6=Zajc|first6=Janja|last7=Zalar|first7=Polona|last8=Grube|first8=Martin|last9=Sun|first9=Hui|last10=Han|first10=James|last11=Sharma|first11=Aditi|last12=Chiniquy|first12=Jennifer|last13=Ngan|first13=Chew Yee|last14=Lipzen|first14=Anna|last15=Barry|first15=Kerrie|last16=Grigoriev|first16=Igor V|last17=Gunde-Cimerman|first17=Nina|title=Genome sequencing of four Aureobasidium pullulans varieties: biotechnological potential, stress tolerance, and description of new species|journal=BMC Genomics|volume=15|issue=1|pages=549|doi=10.1186/1471-2164-15-549|pmid=24984952|year=2014|pmc=4227064 |doi-access=free }}</ref>

The genome of ''A. pullulans'' ''s. str.'' contains large numbers of genes of gene families that can be linked to the nutritional versatility of the species and its stress tolerance.<ref name="Aureobasidium spp. genomes" /> The genome also contains a [[Biology:Homothallism|homothallic]] [[Biology:Mating-type locus|mating-type locus]].<ref name="Aureobasidium spp. genomes" /><ref name=":0">{{Cite journal|last1=Gostinčar|first1=Cene|last2=Turk|first2=Martina|last3=Zajc|first3=Janja|last4=Gunde-Cimerman|first4=Nina|date=October 2019|title=Fifty Aureobasidium pullulans genomes reveal a recombining polyextremotolerant generalist|journal=Environmental Microbiology|volume=21|issue=10|pages=3638–3652|doi=10.1111/1462-2920.14693|issn=1462-2920|pmc=6852026|pmid=31112354|bibcode=2019EnvMi..21.3638G }}</ref> Further genome sequencing of fifty ''A. pullulans'' ''s. str.'' strains showed that the population of the species is homogeneous, with high levels of recombination and good dispersal. The species ''A. pullulans'' was thus recognised as a true [[Earth:Generalist and specialist species|generalist]], able to inhabit a wide variety of habitats with no specialization to any of these habitats at the genomic level.<ref name=":0" /> Despite the presence in the genome of a putative mating locus, and the observation of high recombination rates, no sexual cycle has yet been reported in this organism. {{cn|date=November 2022}}

Due to the relatively recent redefinition of the species, most published work does not yet distinguish between the new species belonging to the previously recognised ''A. pullulans'' species complex. It is therefore not clear to what extent this knowledge is valid for ''A. pullulans'' ''s. str.'' and what should be attributed to the three new species.{{cn|date=November 2022}}
__NOTOC__
==See also==
* ''[[Biology:Aureobasidium melanogenum|Aureobasidium melanogenum]]''
* ''[[Biology:Aureobasidium namibiae|Aureobasidium namibiae]]''
* ''[[Biology:Aureobasidium subglaciale|Aureobasidium subglaciale]]''
* [[Biology:Yeast in winemaking|Yeast in winemaking]]

==References==
{{Reflist}}

==Further reading==
* Themis J. Michailides. {{cite web|title="Above ground fungal diseases", Chapter 27. |url=http://fruitsandnuts.ucdavis.edu/crops/papers/Chapter_27.pdf }}{{dead link|date=July 2017 |bot=InternetArchiveBot |fix-attempted=yes }}
* {{cite journal | last1 = Fleet | first1 = G.H. | year = 2003 | title = Yeast interactions and wine flavour | journal = Int. J. Food Microbiol. | volume = 86 | issue = 1–2| pages = 11–22 | doi=10.1016/s0168-1605(03)00245-9| pmid = 12892919 }}
* {{cite journal | last1 = Falconi | first1 = C.J. | last2 = Mendgen | first2 = K. | year = 1994 | title = Epiphytic fungi on apple leaves and their value for control of the postharvest pathogens ''Botrytis cinerea'', ''Monilinia fructigena'' and ''Penicillium expansum'' | journal = Z. PflKrankh. PflSchutz | volume = 101 | pages = 38–47 }}
* {{cite journal | last1 = Webb | first1 = T.A. | last2 = Mundt | first2 = J.O. | year = 1978 | title = Molds on vegetables at the time of harvest | journal = Appl. Environ. Microbiol. | volume = 35 | issue = 4| pages = 655–658 | doi = 10.1128/AEM.35.4.655-658.1978 | pmid = 646353 | pmc = 242901 | bibcode = 1978ApEnM..35..655W }}
* {{cite journal | last1 = Simon | first1 = L. | last2 = Caye-Vaugien | first2 = C. | last3 = Bouchonneau | first3 = M. | year = 1993 | title = Relation between pullulan production, morphological state and growth conditions in ''Aureobasidium pullulans'': new observations | journal = Journal of General Microbiology | volume = 139 | issue = 5| pages = 979–985 | doi=10.1099/00221287-139-5-979| doi-access = free }}

==External links==
* [http://genome.jgi-psf.org/Aurpu_var_pul1/Aurpu_var_pul1.home.html Genome Page on Mycocosm]

{{Taxonbar|from=Q147300}}

[[Category:Yeasts]]
[[Category:Dothideales]]
[[Category:Epiphytes]]
[[Category:Apple tree diseases]]

{{Sourceattribution|Aureobasidium pullulans}}