Co-expression and in-silico interaction studies for inter-linking the activation of MAPK3 and LOX genes during pathogenesis of Alternaria brassicae in Brassica juncea

Abstract

Alternaria blight disease caused by Alternaria brassicae (Berk) Sacc. is one of the important fungal diseases
of Brassica plant which leads to major yield losses as well as deterioration in quality. Plant responds
toward fungal attack through intricate signal transduction pathways involving MAPKs and jasmonic acid
(JAs) which mediate signaling cascades. Genes in these cascades are co-expressed across diverse conditions,
suggesting the potential underlying co-regulation mechanism. To understand the co-expressed behavior
of genes we have analyzed the expression of LOXs and MAPK3 and it was found that the expression of
BjLOX gene is activated at 3 and 6 h of pathogen infection, where as the expression of MAPK3 were found
to be increased at 3 h, start decreasing at 6 h and completely depressed after 6 h of infection. As the induction
of JA biosynthesis was suggested to require MAPK activation but the defined roles of MAPKs in JA mediated
defense signaling is remain unclear, in-silico protein- protein interaction were applied to understand the
MAPK3 interaction with Lipoxygenase (LOX). Our observations led us to propose that MAPK3 interact
with LOX and it might be playing a role in biosynthesis of JA/JA induced expression of defense genes with
some open questions.