Melanin production by a yeast strain XJ5-1 of Aureobasidium melanogenum isolated from the Taklimakan desert and its role in the yeast survival in stress environments.
The yeast strain XJ5-1 isolated from the Taklimakan desert soil was identified to be a strain of Aureobasdium melanogenum and could produce a large amount of melanin when it was grown in the PDA medium, but its melanin biosynthesis and expression of the PKS gene responsible for the melanin biosynthesis was significantly repressed in the presence of (NH4)2SO4. However, A. melanogenum P5 strain isolated from a mangrove ecosystem grown in both the presence and the absence of (NH4)2SO4 did not produce any melanin. The cell size of A. melanogenum XJ5-1 strain was much higher than that of A. melanogenum P5 strain. The melanized cells of the yeast strain XJ5-1 had higher tolerance to UV radiation, oxidation (200.0 mM H2O2), heat treatment (40 °C), salt shock (200.0 g/L NaCl), desiccation and strong acid hydrolysis (6.0 M HCl) at high temperature (80 °C) than the non-melanized cells of the same yeast strain XJ5-1. At the same time, the melanized cells of the yeast strain XJ5-1 also had higher tolerance to UV radiation, oxidation (200.0 mM H2O2), desiccation and strong acid hydrolysis (6.0 M HCl) at high temperature (80 °C) than A. melanogenum P5 strain, but had similar resistance to heat treatment (40 °C) and salt shock (200.0 g/L NaCl) compared to those of A. melanogenum P5 strain. All the results revealed that many characteristics of A. melanogenum XJ5-1 isolated from the Taklimakan desert soil was different from those of A. melanogenum P5 strain isolated from the mangrove ecosystem.
College of Marine Life Sciences, Ocean University of China, Yushan Road, No. 5, Qingdao, China.
Hong
H
Jiang
College of Marine Life Sciences, Ocean University of China, Yushan Road, No. 5, Qingdao, China.
Nan-Nan
NN
Liu
College of Marine Life Sciences, Ocean University of China, Yushan Road, No. 5, Qingdao, China.
Guang-Lei
GL
Liu
College of Marine Life Sciences, Ocean University of China, Yushan Road, No. 5, Qingdao, China.
Zhe
Z
Chi
Key Laboratory of Protection and Utilization of Biological Resource in Tarim Basin, Tarim University, Xinjiang, China.
Jian-Ming
JM
Wang
Key Laboratory of Protection and Utilization of Biological Resource in Tarim Basin, Tarim University, Xinjiang, China.
Ly-Ly
LL
Zhang
College of Marine Life Sciences, Ocean University of China, Yushan Road, No. 5, Qingdao, China. chi@ouc.edu.cn.
Zhen-Ming
ZM
Chi
D000222:Adaptation, Physiological; D001203:Ascomycota / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism*; D003889:Desert Climate; D005800:Genes, Fungal; D006358:Hot Temperature; D008543:Melanins / Q000096:biosynthesis*; D018384:Oxidative Stress; D011836:Radiation Tolerance; D054712:Salinity; D012988:Soil Microbiology; D013312:Stress, Physiological; D014466:Ultraviolet Rays
D008543:Melanins
Black yeast; Mangrove ecosystem; Melanin; Resistance to harsh environments; The Taklimakan desert