Biochemical profiling of Brassica juncea doubled haploid mutant genotypes under white rust disease stress 

Abstract

White rust, caused by oomycete pathogen Albugo candida, is a serious disease for the crops of Brassicaceae family. It is an obligate pathogen responsible for up to 60% yield loss with combined infection of leaves and inflorescence across the globe. Biochemical variations in host plants can alter the content of proteins, sugars, phenols, iron content etc. enables to understand the biochemistry of host-pathogen interaction. Therefore, the present study was conducted during 2017-2019 at Amity University, Noida, Uttar Pradesh to evaluate the biochemical response of Brassica juncea var. Varuna and its doubled haploid (DH) mutant genotypes infected with A. candida causing white rust at cotyledonary leaf stage. The seven mutant genotypes were tested for pathogenic response against five white rust isolates (WRI). In the challenge assay, mutant genotypes C66 and C69 showed resistance response as compared to susceptible host B. juncea var. Varuna against different isolates on the basis of disease severity. The biochemical parameters were found to be high in the uninoculated genotypes in comparison to infected cotyledons of B. juncea genotypes. The biochemical profile emphasizes significant increase in content of protein, sugar, and phenol from highest in genotype C66 positively correlating with resistance response against pathogen in comparison to other mutant genotype C69 and susceptible check Varuna. The results suggest that factors conditioning the response of mutant genotypes to WRI may differ or control in different ways and triggers novel defense signaling.