Diverse SA, JA and ABA interaction pattern in Brassica juncea and its wild relatives in response to Alternaria brassicae infection.

Title : Diverse SA, JA and ABA interaction pattern in Brassica juncea and its wild relatives in response to Alternaria brassicae infection.

Abstract:

Brassica juncea is a globally cultivated oilseed crop that accounts for approximately 28.6% share of the world’s oilseed production. Alternaria blight caused by Alternaria brassicae is one of the most pressing challenges of all because it causes almost 40-60% yield loss. B. juncea is susceptible to this pathogen however, variable levels of resistance have been reported in some wild relatives of B. juncea like Sinapis alba and Camelina sativa exhibits moderate and high resistance towards A. brassicae.  Phytohormones like SA and JA play a lead role as signal molecules mediating the defense responses in plants by triggering the expression of respective downstream responsive genes. The role of ABA in this intricate signal mechanism is still not fully understood. In this context, we designed an experiment involving three genotypes- B. juncea, S. alba and C. sativa and the response of exogenous application of SA, JA and ABA and its combination with A. brassicae. Selected target genes were biosynthesis genes and downstream responsive genes of SA, JA and ABA signalling pathways. Finally, a quantitative estimation of SA, JA and ABA levels was performed using all the samples comprising various treatments performed in all three genotypes. Overall analysis shows an antagonistic relation between SA, and ABA-JA at gene expression level as well as at the level of hormone accumulation and disease assessment. High levels of JA accumulated in the resistant genotypes show an activated JA-induced response to the pathogen in resistant genotypes which was found suppressed in B. juncea.

Biography:

Dr. Shikha Dixit graduated in the year 2010 with specialization in Agriculture. She then joined University of Agricultural sciences, Bangalore to complete her master’s in Plant Biotechnology. She worked on molecular breeding for drought tolerance and root analysis. She later joined National Institute for Plant Biotechnology for Ph.D. where she worked on plant pathogen interaction and signal transduction mechanism.  She received her doctoral degree in year 2020 after which she worked in Delhi university as research associate on plant-pathogen interaction project. She has published 6 articles in reputed journals and also co-authored book chapter. She was also awarded IARI merit medal for her excellent performance in doctoral program.