Functional Analysis Of Rice Sr Family Genes And Rice Blast Fungi-Secreting Iaa In Rice-pathogen Interaction

Rice is one of the most important crops in China,providing food for more than half of the population.Magnaporthe oryzae,Xanthomonas oryzae pv.oryzae,and Xanthomonas oryzae pv.oryzicola are the cause agent of rice blast,bacterial leaf blight and bacterial leaf streak,respectfully.They are the three main rice diseases,which make great threats and do a lot of harm to rice production.Studying the underlying mechanism of rice-pathogen interaction will not only provide genetic resources for rice breeding but also advance our knowledge towards plant-pathogen interactions.OsDRll is a defense-related gene found through the differentially expressed chip array of rice Minghui 63 inoculation with pathogen.As we have known,tobacco LAMMER kinase PK12 functions by phosphosphorylating RNA splicing factor protein(SR protein).In this study,we analyzed the relationship between OsDRll and rice SR family protein by using yeast two hybrid assay.We also performed bioinformatic analysis for rice SR gene family and investigated their expression patterns after pathogens infection.Mutant analysis of SR genes also provides further insight on their roles in rice-pathogen interaction.In summary,these results show that SR genes are indeed involved in rice-pathogen interactions,but they may not interact with OsDR11.Auxin is a hormone that plays important roles in plant growth and development.The mainly form of auxin in plants is indole-3-acetic acid(IAA).Previous studies show that IAA negatively regulates plant disease resistance.Rice blast fungus can also synthesize IAA,little to none has been reported so far about the function of IAA produced by pathogen in plant-pathogen interactions.In this study,we knocked out two putative IAA biosynthesis genes MoAA03 and MoAMI1-5.We have not found any biological characteristics differences between these mutants and the wild type strain.However,the?MoAMIl mutant remarkly enhanced the pathogen's virulence towards rice compared with the wild type strain.In summary,this study may shed light on understanding the role of pathogen-secreting IAA in rice-blast interaction.