Identification and expression analysis of pathogenicity-related genes in Tilletia indica inciting Karnal bunt of wheat

Abstract

Wheat (Triticum aestivum L.) is a major cereal crop cultivated all over the world. Karnal bunt disease is an internationally quarantined disease caused by Tilletia indica. In modern resistance breeding, effectors have been efficiently used to identify, functionally characterize and deploy resistance genes. The present study was carried out to identify the genes related to pathogenicity in T. indica by mining whole genome sequence and transcriptome data. The secretory proteins were identified using bioinformatics tools. In total, 1337 unique proteins having secretory signatures were predicted in T. indica genome. Out of 192 genes related to host-pathogen interaction (PHI database), 7 pathogenicity-related genes were selected for relative expression analysis at different time points under in vitro and in planta conditions using qPCR. Under in vitro, maximum expression of genes was up to 3 fold on amendment with spike tissue extract from susceptible host. Under in planta, three genes (Ti2035, Ti2347 and Ti3774) showed the maximum expression at 3 days post inoculation (dpi). Further two genes (Ti57 and Ti198) showed the maximum up-regulation at 3 dpi followed by 10 dpi and 15 dpi. Two genes (Ti10340 and Ti12741) were up regulated at later stages at 10 dpi and 15 dpi only in susceptible genotype. Ti2035, Ti2347 and Ti3774 genes might have role in penetration, Ti57 and Ti198 genes may be related to penetration & infection, Ti10340 and Ti12741 genes may have role in sporulation when co-related with earlier reported histo-pathological studies. This study could be utilized to understand the mechanism(s) of pathogenesis through functional genomics for developing strategies for management of Karnal bunt of wheat.