Variable Secondary Metabolites for Defense Against Chilo Partellus (Swinhoe) and Sesamia Inferens (Walker) in Maize.

Abstract

Inbuilt biochemical plant defense is the most reliable and sustainable solution to combat insect pest attacks. The stem borers, Chilo partellus (Swinhoe) and Sesamia inferens (Walker), are major threats to maize production in tropical countries of the world. Present study was carried out on host selection behaviour, antibiosis and induced biochemical defense against these borer species. The study revealed that CPM 15 and CML 345 were less preferred, took greater time in host establishments, and exhibited antibiosis against C. partellus and S. inferens in comparison to other test genotypes. Damage caused by Sesamia inferens resulted in higher levels of total proteins, sugars, starch, carotenoids, phenols, ferric ion reducing powder, antioxidants, catalase, ascorbate peroxidase, ascorbate oxidase, phenylalanine ammonia lyase (PAL), and tyrosine ammonia lyase (TAL) compared to C. partellus across the test genotypes. However, C. partellus damage increased, and S. inferens decreased total lipids in all the test genotypes. In the case of C. partellus, 97.6% variability in larval preference was explained by catalase and ascorbate oxidase; 93.4% variability in host establishment time by total proteins, sugars and phenols; and 93.5% variability in antibiosis by total proteins, sugars and ascorbate peroxidase. However, 96.7% variability in larval preference was explained by total proteins, sugars, phenols and PAL; 96.1% variability in time to establish by starch alone; and 91.9% variability in antibiosis by ascorbate oxidase and TAL in the case of S. inferens. Finally, although more than 90% of the variability in larval preference and antibiosis was explained by various induced biochemicals, no common biomolecule was identified among the test genotypes that could defend against C. partellus and S. inferens.