Plants, being sessile, are exposed to an array of abiotic and biotic stresses. To adapt towards the changing environments, plants have evolved mechanisms that help in perceiving stress signals wherein
phytohormones play a critical role. They have the ability to network enabling them to mediate defense responses. These endogenous signals, functioning at low doses are a part of all the developmental stages of the plant.
Phytohormones possess specific functions as they interact with each other positively or negatively through cross-talks. In the present study, variations in the amount of
phytohormones produced during biotic stress caused due to Magnoporthe grisea
infection was studied through targeted metabolomics in both primed and control finger millet plants. Histochemical studies revealed
callose deposition at the site of pathogen entry in the primed plants indicating its role during plant defense. The knowledge on the genetic makeup during
infection was obtained by quantification of
MAP kinase kinases 1 and 2 (MKK1/2) and
lipoxygenase (LOX) genes, wherein the expression levels were high in the primed plants at 6 hours post-inoculation (hpi) compared to mock-control. Studies indicate the pivotal role of
mitogen-activated protein kinase (MAPK or MAP
kinases) during defense signalling. It is the first report to be studied on MAPK role in finger millet-blast disease response. Temporal accumulation of LOX
enzyme along with its activity was also investigated due to its significant role during
jasmonate synthesis in the plant cells. Results indicated its highest activity at 12 hpi. This is the first report on the variation in
phytohormone levels in fingermillet - M. grisea pathosystem upon priming which were substantiated through
salicylic acid (SA) pathway.