BOxO Gene Confers Resistance against Stem Rot in Brown Mustard

Researchers from the University of Delhi reported the potential of the barley oxalate oxidase (BOxO) gene in conferring stable resistance against stem rot in a productive and highly susceptible brown mustard (Brassica juncea cv Varuna) under field conditions. The findings are published in Transgenic Research.

Stem rot caused by the oxalic acid-secreting necrotrophic fungal pathogen Sclerotinia sclerotiorum, causes significant yield losses in the Brassica crops. Oxalate oxidase can metabolize oxalic acid to carbon dioxide and hydrogen peroxide. When oxalic acid is degraded during the early phase of fungal–host interaction, it can interfere with the fungal infection and establishment processes. Thus, the research team genetically engineered the BOxO gene to confer stem rot resistance in brown mustard. Four transgenic lines exhibited a significant reduction in the rate of lesions, indicating enhance resistance to stem rot. Furthermore, the enhanced resistance in the transgenic lines correlated with high oxalate oxidase activity, accumulation of higher levels of hydrogen peroxide, and activation of defense responsive genes upon infection by S. sclerotiorum.