Unraveling defense strategies: gene expression dynamics in blast-resistant vs. susceptible aromatic rice landraces

Abstract

In this study, efforts were made to understand the defence responses in resistant and susceptible aromatic landraces against the rice leaf blast pathogen, Magnaporthe oryzae. Four resistant genotypes (Benugopal, Manas, Karpurkali, and Kalazeera) and two susceptible genotypes (Kalikati 2 and Kalikati 1) underwent biochemical analysis in relation to blast disease. The results of the biochemical analysis revealed increased enzyme activity levels, namely peroxidase, phenylalanine ammonia-lyase, polyphenol oxidase, superoxide dismutase, and catalase, in the resistant genotypes (Benugopal (AC44184) and Karpurkali (AC44155)) in comparison to the susceptible ones [Kalikati 2 (AC44236) and Kalikati 1 (AC44156)]. The same trend has been seen in the assays for β-1,3-glucanase and total phenols. RT-qPCR evaluation has been performed to establish the expression levels of PO, PAL, PPO, SOD, and CAT in the four resistant genotypes and the two susceptible ones after inoculation with M. oryzae (RLB 06) at various time intervals. Noteworthy variations in defence gene expression were noted among the genotypes. The expression of defence genes was upregulated in the resistant genotypes [Benugopal (AC44184) and Karpurkali (AC44155)] compared to their susceptible ones. Gene expression studies result indicated that the relative defence genes expression levels related to the spectrophotometric data.