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Antioxidant-Mediated Survival of Primed Finger Millet Plants against Blast Disease

Savita Patil: Jain University

<div>Ragi or finger millet (<em>Eleusine coracana</em>) is an indispensable crop in the arid, semi-arid regions of India and countries in Eastern Africa with proven resilience to climate change. It is now being promoted globally to combat malnutrition and calcium deficiency. Blast, caused by <em>Magnaporthe grisea</em>, causes annual yield losses of ~80%. <em>M. grisea </em>is a virulent pathogen on several graminaceous hosts. Seed-priming with bacteria induce antioxidants that act as signaling molecules and alter cellular patterns of the host that enhance resistance during the early stages of infection. The objectives of this study were: (i) to select rhizobacteria that promote growth and induce disease resistance; (ii) to evaluate disease resistance by assessing the temporal accumulation of enzymatic and non-enzymatic antioxidants; (iii) to deduce the metabolic profile in primed versus the control plants. Two fluorescent <em>Pseudomonas </em>isolates JUPC113 (GenBank ID. KX010601) and JUPW121 (GenBank ID. KX010602) were used to prime ragi cv Indaf 9 seeds. JUPC121-primed plants inoculated with <em>M. grisea </em>exhibited blast incidence 92% lower with increased vigor index (3064.00±3.06) than un-primed plants. Significant increases in antioxidant activities and the activities of tyrosine ammonia lyase and phenylalanine ammonia lyase were observed early in primed plants. There was also increased benzoic acid accumulation, a precursor of salicylic acid pathway along with the accumulation of lignin and callose as mechanical barriers for pathogen entry. Gene expression studies during induction of resistance are in progress to deduce the coordinated role of rhizosphere microbes. Development of different formulations for field testing is ongoing.</div>