Molecular insights on differential responses of antioxidant and pathogenesis-related genes in pigeonpea [Cajanus cajan (L.) Millsp.] to Fusarium wilt (Fusarium udum (L.)

Abstract

Background: Pigeonpea [Cajanus cajan (L.) Millsp.] is a major dietary protein source to a large vegetarian population in the world. However, Fusarium wilt (FW) caused by Fusarium udum Butler (FU) is one of the challenging factors to pigeonpea production. FW resistance in pigeonpea is restricted to specific agro-climatic zones. Therefore, exploring a superior pigeonpea genotype from landraces or local cultivars cultivated in various rural regions and validating its resistance response at biological and molecular level could be an alternative to crop improvement program. The present study was carried out to identify superior genotypes of pigeonpea through selection of innate resistance to FW using different biological and molecular approaches.Result: Five distinct genotypes of pigeonpea along with well-known one resistant (ICP2894) and susceptible (ICP2376) control were selected on the basis of percentage of FW disease incidence from three different states of India after an extensive survey work. Among them, Richa had shown very less FW incidence (10.0%) under genotype evaluation study and was further selected for experimental validation at molecular level for its innate resistance to FW. Molecular characterization and expression profiling of biotic stress responsive genes representing antioxidant enzymes (APX and SOD) and Pathogenesis related proteins (CHS and β-1,3-glucanase)families were carried out. Under FU challenged conditions in Richa, expression patterns of both AO genes found to be similar, while expression of both PR genes was gradually increased with inoculation time. Putative 3D protein structure of CHS and SOD were generated. Molecular docking with fungal effect or protein cellobio-hydrolase-c (CBH-c) also revealed that their role in blocking the hydrolytic activity of CBH-c during pathogen invasion. Conclusion: The obtained results of expression study and in-silico analysis showed that the higher level of induction of PR and AO genes and strong interaction of their putative proteins with fungal CBH-cprotein established their antifungal activity conferring early plant defense responses to restrict the pathogen growth in resistant genotype Richa. Our study displaying a strong and combinatorial approach involving biological assay, molecular experiment and in-silico analysis to identify a superior genotype of pigeonpea resistant to FW across a major biogeographic region.

Molecular Analysis of Disease-Responsive Genes Revealing the Resistance Potential Against Fusarium Wilt (Fusarium udum Butler) Dependent on Genotype Variability in the Leguminous Crop Pigeonpea

“…The authors are also thankful to Legumes Pathology, ICRISAT, Hyderabad, India for providing biological samples to conduct the study. This manuscript has been released as a pre-print at ( https://www.researchsquare.com/article/rs-7107/v1 ), ( Biswas et al, 2019 ).…”