Abstract

WRR-BjuD encodes a CC-NB-LRR Protein that Confers White Rust Resistance in Brassica juncea to different Isolates of Albugo candida

HEENA ARORA, PhD Student, SOUTH CAMPUS, UNIVERSITY OF DELHI

White rust caused by A. candida is a destructive disease in many agronomically important Brassica species including B. juncea, the major oilseed crop of India. All the released varieties of B. juncea in India are highly susceptible leading to yield losses of 60% or more. Therefore, there is an urgent need to develop white rust resistant B. juncea varieties. In a previous research initiative locus conferring resistance to A. candida was mapped to LG A05 in an east European gene pool line, Donskaja-IV. We attempted to identify and functionally validate white rust resistance gene in Donskaja-IV. We found that the locus of Donskaja-IV contains a single Resistance gene of the CNL class which has not been previously reported. This R-gene appeared to be the most probable candidate for conferring white rust resistance in Donskaja-IV. Functional validation was performed by raising transgenics in susceptible variety Varuna expressing the candidate gene. Study of the disease response by the transgenics against A. candida isolates, collected from seven geographical regions confirmed the role of the transgene in conferring complete and broad spectrum resistance to disease. This is the first resistance gene to be characterized in B. juncea with an objective of reducing the influence of A. candida on the yield of mustard.