Salicylic acid seed priming induces systemic acquired resistance to Fusarium fujikuroi in aromatic rice

Fusarium fujikuroi is a pathogenic fungus, causing bakakae disease in rice, known for its detrimental impact on aromatic rice, causing significant yield losses. This study intended to investigate the efficacy of seed priming with salicylic acid (SA) for the induction of systemic acquired resistance (SAR) against bakanae infection in two aromatic rice cultivars, PB 1121 and PB 1509, under field conditions. Seed priming was done with SA at 10 mg/l for 6 h, followed by inoculation with pure cultures of F. fujikuroi for 24 h. Seed priming with salicylic acid effectively reduced disease incidence as compared to positive controls. The tissues of the positive control of both cultivars showed severe structural deformities, with evident pathogenic structures in roots, stems, and leaves. Priming with SA strengthened rice seedlings against pathogen progression by having higher lignin content, peroxidase activity, net photosynthetic rate, stomatal conductance, and photosynthetic pigments while reducing hydrogen peroxide content, endogenous levels of GA3 and IAA, and increasing endogenous ABA levels as compared to both positive and negative controls. The knowledge gained from studying the histological and biochemical changes in infected and un-infected plant components post-SA priming can lead to the development of sustainable management of bakanae disease in rice. This study holds significant implications for understanding SA-induced systemic acquired resistance against bakanae disease in rice.