Proteomic Profiling On The Strain Degeneration Mechanism Of Nematophagous Fungus Pochonia Chlamydosporia

Nematophagous fungus Pochonia chlamydosporia is an important microbial resource for development of biocontrol agent against plant parasitic nematodes. P. chlamydosporia YMF 1.1301 was the strain using to produce the first commercial nematicidal agent (Xian Chong Bi Ke) in China. The degeneration of P. chlamydosporia YMF 1.1301 negatively influenced the control effect and application of the agent. Understanding the mechanism of fungal degeneration would be beneficial for strain development and selecting suitable conservation method. In this study, P. chlamydosporia YMF 1.1301 was used as the original strain to screen its degenerative strain. The degradation mechanism of P. chlamydosporia YMF 1.1301 was analyzed by method of comparative proteomics. The main results obtained were concluded as the follow.1. The degenerative strain YMF 1.613 was generated which showed degeneration characteristics respectively on the conidial biomass and serine protease concentration. Conidial biomass and serine protease concentration of YMF1.613 were 1.75 x 106 per dish and 49.97 μg/mL, but for YMF 1.1301, they were 3.19×107 per dish and 232.83 μg/mL.2. The protein-coding genes were predicted by method of ab initio gene finding, which generated 12,781 genes, and 8,409 genes were annotated by methods of GO and COG.3. Analysis by method of differential proteomics, comparing with YMF 1.1301, YMF 1.613 generated 19 down-regulated protein which involved in 11 functional categories, and 426 up-regulated proteins involved in 18 functional categories.4. The degradation mechanism of P. chlamydosporia YMF 1.1301 involved (a) the proteins (eg. Rho GTP), which regulated signal transduction pathway about cellular growth, were down-regulated and resulted the strain grew slowly; (b) the key enzymes (eg. Cytokinin oxidase) which regulated the cellular growth, differentiation, were down-regulated, which slowed down growth rate; (c) the proteins (eg. Prohibitin), which regulated cellular aging, apoptosis and autophagy pathway, were up-regulated which inhibited the cell growth; (d) the proteins (eg. Chitobiase), which regulated the cell wall synthesis pathway, were down-regulated, which reduced the conidial biomass and the growth of the strain.