The Influence Of Aquaglyceroporin StFPS1Gene On The Growth, Development And Invasion Ability Of Setosphaeria Turcica

Aquaglyceroporin StFPS1gene of Setosphaeria turcica had been cloned in ourprevious research. Based on this above research, RNAi technology was used to obtainStFPS1silencing mutant. The growth, development, invasion ability and response tohyperosmotic stress of the RNAi transformants were studied in comparison with wildtypestrain (WT). The main findings were as follows:(1) Based on the basic plasmid pSilent-1, a gene RNAi vector of StFPS1wasconstructed. The recombinated vector was transformed to the protoplasts of S. turcica. Byscreening the RNAi transformants based on the resistance of hygromycin B and detectingby RT-PCR, two transformants named fps1-1and fps1-2were obtained. Real-time RCRtechnique was further employed to determine StFPS1gene expression levels in thesetransformants. The results showed that the expression quantity of StFPS1in fps1-2andfps1-1was5.49%, and0.34%respectively compared with WT.(2) The growth rate and conidium yield of the transformants reduced compared withWT. More importantly, fps1-1, the higher silencing efficiency transformant, did not formconidium. The results showed that StFPS1affected the growth and development ofmycelium and spore production of S. turcica.(3) The growth rate of the transformant colonies was inhibited, and the hyphal cellsturned swollen under0.5M NaCl hyperosmotic stress treatment compared with the wildtype strain. Mycelium partition increased, and spacing turned short, contents and glycerolalso increased compared to WT. The results showed that StFPS1gene involved in responseof Setosphaeria turcica to hyperosmotic stress.(4) Compared to WT, the cells of the transformants fps1-2appeared the retardation ofappressorium development, and fps1-1could not penetrate cellophane, suggestting thatStFPS1affect the development of appressorium and then impact the penetration capacity.(5) Compared with WT, the cell walls of transformant fps1-1was significantly thinnerby observation with transmission electron microscopy. The transformants became lesssensitive to cell wall synthesis inhibitors, such as Congo red, CFW, SDS. The resultsillustrated that StFPS1was closely related to the morphogenesis of the cell wall of.Setosphaeria turcica.(6) The expression of the key genes in HOG-MAPK and CWI-MAPK cascadepathway, such as StSHO1, StHOG1, StSLT2, was detected using real-time RCR technique.The expression level of StSHO1, StHOG1, StSLT2decreased significantly. Thus, thesilencing of StFPS1not only interfered with the HOG pathway, but also the cell wallintegrity (CWI) pathway.