Amino and fatty acids contributing to antibiosis against Chilo partellus (Swinhoe) in maize

Abstract

Certain amino and fatty acids play essential role in plant–herbivore interactions and also act as precursors for various plant defense compounds. Therefore, we carried out amino and fatty acid profiles of seedlings of different specialty maize genotypes viz., quality protein maize (high lysine and tryptophan contents in the kernels), sweet corn, white kernel and yellow kernel, and their fed Chilo partellus larvae to understand their contribution in plant defense. The larval and pupal weights, larval survival, adult emergence, and antibiosis indices of C. partellus were significantly lower on white and yellow kernel than that on sweet corn and quality protein maize genotypes. The amino and fatty acid contents varied significantly in the seedlings of test maize genotypes and in their fed C. partellus larvae. Amounts of aspartic acid, glycine, histidine, phenylalanine, proline, serine, and threonine were significantly lower in the seedlings of white kernel as compared to other maize genotypes. However, the amounts of these amino acids were significantly higher in the C. partellus larvae fed on white kernel as compared to those fed on other maize genotypes. Furthermore, amounts of basic, aliphatic, and cyclic amino acids were also lower in the seedlings of white kernel genotypes and higher in their fed C. partellus larvae as compared to other test maize genotypes and their fed insect larvae. The increase or decrease in myristic, cinnamic, linoleic, stearic, methyl-11-eicosanoate, and margaric acid contents in the maize seedlings and their fed C. partellus larvae followed consistent trend. Myristic and stearic acids were significantly higher in the seedlings of white kernel than other maize genotypes. Amino acids viz., aspartic acid, glycine, histidine, lysine, phenylalanine, proline, serine, and threonine; and the fatty acid, stearic acid in the test maize genotypes showed significant association with various growth and development indices, and contributed to 100% variability in antibiosis against C. partellus, which could be used as biomarkers to identify spotted stem borer-resistant maize genotypes.