PsHint1,associated with G-protein alpha subunit PsGPA1,is required for chemotaxis and virulence in Phytophthora sojae

【作者】 张鑫； Chunhua Zhai； Min Qiu； Yujuan Hao； Pingping Nie； Wenwu Ye； Yuanchao Wang；

【Author】 Xin Zhang;Chunhua Zhai;Min Qiu;Yujuan Hao;Pingping Nie;Wenwu Ye;Yuanchao Wang;Department of Plant Pathology,Nanjing Agricultural University;

【机构】 Department of Plant Pathology,Nanjing Agricultural University；

【摘要】 Phytophthora sojae is an oomycete plant pathogen and is one of the most important pathogens of soybean,causing root and stem rot.Zoospore is a key stage in the life cycle of P.sojae.The chemotaxis of zoospore to isoflavones is believed to be critical for host recognition and initiating infection.G protein a subunit,PsGPA1,plays a key role in chemotaxis of P.sojae.In this study,we used the affinity purification approach to identify proteins that physically associate with PsGPA1.One of the PsGPA1-interacting proteins identified was a HIT-domain-containing protein orthologues to human HINT1,namely PsHintl.The PsHintl protein interacted with both GTP and GDP form of PsGPA1.Analysis of gene silencing mutants indicated that PsHintl plays a role in chemotropic response of zoospores to isoflavones.In addition,the PsHintl-silenced mutants were defective in cyst germination,and formed abnormal germ tubes with highly branched and apical swelling.During interaction with a susceptible soybean cultivar,the soybean cells inoculated with PsHintl-silenced mutants exhibited strong defense responses accompanied with accumulation of reactive oxygen species(ROS).The PsHint1-silenced mutants displayed a significant reduction in infectious hyphal extension and caused a decrease in pathogenicity.Interestingly,transcriptional patterns of several P.sojae RxLR effectors were altered in the PsHintl-silenced mutant.These results suggest that PsHintl may interact with PsGPA1 to regulate chemotaxis to soybean isoflavones and pathogenicity.更多还原

【Abstract】 Phytophthora sojae is an oomycete plant pathogen and is one of the most important pathogens of soybean,causing root and stem rot.Zoospore is a key stage in the life cycle of P.sojae.The chemotaxis of zoospore to isoflavones is believed to be critical for host recognition and initiating infection.G protein a subunit,PsGPA1,plays a key role in chemotaxis of P.sojae.In this study,we used the affinity purification approach to identify proteins that physically associate with PsGPA1.One of the PsGPA1-interacting proteins identified was a HIT-domain-containing protein orthologues to human HINT1,namely PsHintl.The PsHintl protein interacted with both GTP and GDP form of PsGPA1.Analysis of gene silencing mutants indicated that PsHintl plays a role in chemotropic response of zoospores to isoflavones.In addition,the PsHintl-silenced mutants were defective in cyst germination,and formed abnormal germ tubes with highly branched and apical swelling.During interaction with a susceptible soybean cultivar,the soybean cells inoculated with PsHintl-silenced mutants exhibited strong defense responses accompanied with accumulation of reactive oxygen species(ROS).The PsHint1-silenced mutants displayed a significant reduction in infectious hyphal extension and caused a decrease in pathogenicity.Interestingly,transcriptional patterns of several P.sojae RxLR effectors were altered in the PsHintl-silenced mutant.These results suggest that PsHintl may interact with PsGPA1 to regulate chemotaxis to soybean isoflavones and pathogenicity.更多还原