Biochemical Alterations in the Leaves of Resistant and Susceptible Mungbean Genotypes Infected with Mungbean Yellow Mosaic India Virus

Abstract

Mungbean (Vigna radiata), an important leguminous crop, is highly susceptible to yellow mosaic disease (YMD) caused by Mungbean yellow mosaic India virus (MYMIV), resulting in high yield penalty. Previously, different varieties of mungbean have been reported possessing resistance/ tolerance against MYMIV. However, the molecular events occurring during compatible and incompatible interactions between mungbean and MYMIV are yet to be explored. Therefore, in this study using MYMIV-resistant (NM-2016), moderately resistant (NM-2011) and susceptible genotype (VC-1647C), alterations in various biochemical attributes due to MYMIV infection were analysed and compared with healthy non-inoculated control plants for understanding the resistance mechanism. After MYMIV inoculation, the level of total phenolic contents (TPC) and total soluble proteins (TSP) increased significantly in the susceptible genotype. However, the level of Malondialdehyde (MDA) and Ascorbate peroxidase (APX) remained same in all the genotypes. Level of superoxide dismutase (SOD) and catalase (CAT) decreased in the susceptible genotype but CAT level increased in the moderately resistant genotype. Protease level decreased significantly in all the genotypes while esterase level increased in moderately resistant and susceptible genotype. Peroxidase (POD) increased only in moderately resistant genotype and Total Oxidant Status (TOS) increased significantly in the susceptible genotype. Due to MYMIV infection the level of all plant pigments decreased in all the genotypes tested. The comparative proteome analysis using SDS-PAGE resolved 22 peptides with molecular weight from 12.5 to 163 kDa. Differential expression of protein phosphatase 2C (PP2C) and Cytochrome b6 (Photosynthesis) in resistant and moderately resistant genotypes; Pectin acetyl esterase and Resistant specific protein-1(4) in resistant genotype and up-regulation of superoxide dismutase [Cu-Zn] and RuBisco by MYMIV may have triggered signal transduction pathway and consequently induced a resistance response against MYMIV in V. radiata by activating PR proteins.