Volatile organic compound-induced metabolic and biochemical reprogramming in Zingiber officinale for resistance to Pythium myriotylum

Abstract Rhizome rot, caused by Pythium myriotylum (P. myriotylum), is a significant constraint on ginger cultivation, necessitating the development of sustainable defense strategies. The present study, therefore, evaluated the capacity of the monoterpenes Geraniol, Eugenol, and Linalool to function as priming agents for resistance induction in cultivated ginger. Our comprehensive evaluation of the defense response, employing biochemical and metabolomics approaches, revealed that Geraniol emerged as the most effective candidate, significantly reducing disease severity in infected plants. Biochemical analysis demonstrated that Geraniol-primed infected plants exhibited a notable enhancement in defense-related compounds and enzymatic activities compared to infected plants. Geraniol primed plants showed elevated levels of phenolics, flavonoids, anthocyanin, and lignin, with increased activities of Phenylalanine Ammonia Lyase (PAL) enzyme. Metabolomics profiling studies identified significant shifts in secondary metabolism, highlighting the accumulation of key defense-related metabolites in primed plants. The findings of the study strongly suggests that Geraniol effectively primed the ginger defense system, leading to a faster and stronger induction of both constitutive and induced defenses upon P. myriotylum challenge. Geraniol priming proved to be a promising, eco-friendly strategy for managing P. myriotylum-induced rhizome rot in ginger.