Function Analysis Of Rab GTPase PsVPS21 In Phytophthora Sojae

Soybean is one of the most important economic products in the world, Phytophthora sojae is the soybean pathogen responsible for the soybean root rot disease, It makes the soybean oneset in each growth period.If the infection happened before the emergence of soybean,it would cause seed rot or plants dead.If the pathogen infected soybean after the emergence of soybean,it could cause the soybean root rot or stem rot,witch leads to seedlings wilting or death. Phytophthora sojae is a highly destructive disease on soybean.In 1948,it was found in Indiana of United States for the first time,then,it was found in other counties of origin.In 1986, the soybean root rot disease was identified as A1 entry quarantine.At present,the disease has occurred in Asia,Europe,North and South America,ang Oceania,and the damage caused by it surpass one billion dollor every year.So,it is very critical to study the soybean pruduct and control of root rot disease,at the same time,what the research hot spot is pathogenesis of the infection process.It is more clear about the pathogenesis of the infection process with the continuous development and improvement of molecular biology. The researchs over the past few years show that the process of infection about the interaction of pathogen and host needs the adjustment of transportation and distribution about various kinds of proteins in cells,it plays a key role in the process of infection.In this paper we use these technologys to analysis the gene PsVPS21 about the mechanism of vesicle formation and transpotation include bio-information,Real-time PCR,gene silencing technology, we hope to explain the role PsVPS21 played in the process of infection.Bioinformatics prediction and transcription analysis of Rab GTPase family in phytophthora sojae.Rab GTPase family is the largest sub-family in small GTPase family,it locates on special cell membranes.The researches show that Rab protein regulate the vesiciles formation and transportation by its regulatory protein of upstreams and downstreams.Rab protein is very conservative in eukaryotic cells,participates in several signal transduction pathways,such as cell polarity,cell movement,cell shape,the interaction between endoplasmic reticulum and golgi body.It plays a key role in fungal growth and pathogenic process. In this study, we predicted putative VPS21 coding genes in the genome of P. sojae, P. ramorum, P. infestans, H. Arabidopsis, Pythiu according to the sequences and domains from reported VPS21 in other organisms.PsVPS21 own conservative GTP protein,this shows VPS21 is very conservative in the process of evolution. In P. sojae, the transcription profile of putative VPS21 was also performed by RNA-sequencing.At mycelium stage, sporangium stage and five infection stages in the transcriptome of the P. sojae, and PsVPS21 expresses stablely. Therefore the bioinformatics of VPS21 in P. sojae provided a good platform for further characterization.PsVPS21 is involved in growing development, the formation of oospores and pathogenicity in Phytophthora sojae.VPS21 is one member of Rab5 family,a monomer GTP binding protein,it can combine with GTP then hydrolysis it. PsVPS21 is highly conserved in sequenced oomycetes and fungi. To elucidate the function, the expression of PsVPS21 was silenced by stable transformation of P. sojae,and by this,we get 3 silence mutants (T46 T88 T126). Phenotypes of the silenced transformants in comparison to non-silenced strains were evaluated throughtout the life cycle. The silencing of PsVPS1 was not associated with differences in the swimming of zoospores, chemotaxis.However, the hyphal growth rate were markedly reduced by silencing, and cyst germination showed abmormal, with apical swelling of hyphae and branching. Furthermore polysaccharides were markedly affected on their distribution by staining. Silenced mutant could penetrate epidermis cells, but could not expand on susceptible cultivar. PsVPS21-silenced mutant less oospores than the wild type. PsVPS21-silenced mutants reduced the secretion of extracellular peroxidase in contrast to wild types on solid plates,and more sensitive to endoplasmic reticulum stress.