Expression Divergence Of Rice Orthologous Genes In Response To Blast Fungal Infection

Rice(Oryza sativa L.)is one of the most important crops that serves as stable food for-50%of human population.Some important agronomic traits that enable rice to cope with numerous abiotic and biotic stresses have been retained and enhanced in rice domestication.Knowledge on how expression divergence of conserved genes gradually leads to phenotypic differentiation under biotic stress condition is still limited.In this research,we compared RNA-seq data between a japonica rice cultivar Nipponbare and an indica rice cultivar 93-11 inoculated with the filamentous ascomycete fungus Magnaporthe oryzae(Pyricularia oryzae),which causes great loss to rice production worldwide.The different responsive genes that detected between two rice cultivars indicated their potential divergent mechanisms in response to infection.In addition,the variable expression patterns were observed in some evolutionary conserved orthologous genes and further analysis of them revealed the positive correlation between their expression divergence and the nucleotide diversity in promoter.Strikingly,these variations in promoter region directly lead to the divergence of transcription factor binding sites and subsequently influence binding of transcription factor and transcriptional regulation,which may primarily contribute to the difference of these two rice cultivars in response to blast fungal infection.From these results,we asserted that variation in the expression pattern of these orthologous genes in the two rice cultivars may constitute an evolutionary alternative that distinguishes the two genetically diverse rice cultivars in response to M.oryzae infection.