A Comparative Study of SA-JA-ABA Cross-talk in Response to Alternaria Brassicae in Susceptible and Resistant Brassica Species

Past research has established that the disease resistance mechanism in plants is regulated by SA and JA-mediated pathways. However, the involvement of ABA in SA-JA cross-talk have gained attention due to the diverse role of ABA in disease resistance. Depending on the phyto-patho system ABA can be a positive or a negative regulator. In terms of the A. brassicae-brassica system, the role of ABA as a regulator has not been established assertively. This study explored the variation in phytohormone signaling in susceptible B. juncea and its resistant wild relatives. Our study revealed a significant difference in the initial trigger of phytohormone signaling with 3hrs of inoculation in susceptible and tolerant genotypes. Also, it was established that the higher ABA production within early hours in susceptible species triggers SA production and H2O2 accumulation which in turn favored the pathogen. Contrastingly, in the resistance genotype ABA accumulation was not noticed which led to robust JA mediated defense and a resistance phenotype was noticed.The funding for this research was provided by ICAR-National Institute for Plant Biotechnology, New Delhi Indi