Os2 MAP kinase-mediated osmostress tolerance in Penicillium digitatum is associated with its positive regulation on glycerol synthesis and negative regulation on ergosterol synthesis.
High osmolarity glycerol (HOG) pathway is ubiquitously distributed among eukaryotic organisms and plays an important role in adaptation to changes in the environment. In this study, the Hog1 ortholog in Penicillium digitatum, designated Pdos2, was identified and characterized using a gene knock-out strategy. The ΔPdos2 mutant showed a considerably increased sensitivity to salt stress and cell wall-disturbing agents and a slightly increased resistance to fungicides iprodione and fludioxonil, indicating that Pdos2 is involved in response to hyperosmotic stress, regulation of cell wall integrity and sensitivity to fungicides iprodione and fludioxonil. Surprisingly, the mutant was not affected in response to oxidative stress caused by H2O2. The average lesion size in citrus fruits caused by ΔPdos2 mutant was smaller (approximately 25.0% reduction) than that caused by the wild-type strain of P. digitatum at 4 days post inoculation, which suggests that Pdos2 is needed for full virulence of P. digitatum. Interestingly, in the presence of 0.7 M NaCl, the glycerol content was remarkably increased and the ergosterol was decreased in mycelia of the wide-type P. digitatum, whereas the glycerol content was only slightly increased and the ergosterol content remained stable in the ΔPdos2 mutant, suggesting that Pdos2-mediated osmotic adaption is associated with its positive regulation on glycerol synthesis and negative regulation on ergosterol synthesis.
Institute of Biotechnology, Zhejiang University, Hangzhou, China.
Mingshuang
M
Wang
Institute of Biotechnology, Zhejiang University, Hangzhou, China.
Changsheng
C
Chen
Institute of Biotechnology, Zhejiang University, Hangzhou, China.
Congyi
C
Zhu
Institute of Biotechnology, Zhejiang University, Hangzhou, China.
Xuepeng
X
Sun
Institute of Biotechnology, Zhejiang University, Hangzhou, China.
Ruoxin
R
Ruan
Institute of Biotechnology, Zhejiang University, Hangzhou, China. Electronic address: hyli@zju.edu.cn.
Hongye
H
Li
D002957:Citrus / Q000382:microbiology; D004875:Ergosterol / Q000096:biosynthesis*; D005656:Fungal Proteins / Q000235:genetics / Q000378:metabolism*; D015966:Gene Expression Regulation, Fungal; D005990:Glycerol / Q000378:metabolism*; D020928:Mitogen-Activated Protein Kinases / Q000235:genetics / Q000378:metabolism*; D009995:Osmosis; D010407:Penicillium / Q000737:chemistry / Q000201:enzymology* / Q000235:genetics / Q000378:metabolism; D010935:Plant Diseases / Q000382:microbiology
D005656:Fungal Proteins; D020928:Mitogen-Activated Protein Kinases; D005990:Glycerol; D004875:Ergosterol
Cell wall integrity; Os2 mitogen-activated protein kinase; Osmotic adaption; Penicillium digitatum; Regulation of ergosterol synthesis