Exogenous Salicylic Acid Induces Metabolite Production Conferring Foot Rot Resistance in Black Pepper

A study on biochemical factors involved in black pepper defense response against Phytophthora sp. on exogenous application of salicylic acid was carried out in Phytophthora sp. susceptible variety Panniyur 1. Total phenol content and total flavonoid content were studied under different concentration of salicylic acid to know the performed and induced responses. The pathogen was inoculated (soil inoculation) seven days after treatment application and plants were observed for changes at 24, 48 and 72 HAI. Leaves samples were subjected for biochemical analysis. Although total phenolic content remained relatively stable across treatments, the highest levels were observed in plants treated with 1500 ppm SA, while healthy controls exhibited the lowest. A general decline in phenolic content at 48 HAI followed by an increase at 72 HAI was noted. Similarly, flavonoid content showed a decrease at 48 HAI, with a subsequent rise at 72 HAI, with maximum accumulation recorded in plants treated with 1500 ppm SA. Overall, the results suggest that exogenous application of SA enhances phenolic and flavonoid production, thereby strengthening the defense response in black pepper against Phytophthora infection.