Stress-induced defense in sorghum in response to attack by the spotted stem borer, Chilo partellus (Swinhoe)

There is a complex interplay of biochemical interactions which determine the host plant reaction to herbivory. We studied the Chilo partellus-induced biochemical plant defense system in sorghum. Present studies found that the total protein, starch and total sugar contents were significantly lower, while antioxidant enzymes like ascorbate oxidase (AO), catalase (CAT), ascorbate peroxidase (APX), phenyl ammonia lyase (PAL), tyrosine ammonia lyase (TAL), and nonenzymatic antioxidants such as total phenols, total antioxidants and ferric ion reducing antioxidant power (FRAP) higher in the seedlings of all the test sorghum genotypes as compared to susceptible genotype, Swarna both under healthy and C. partellus damaged conditions. Further, the C. partellus damage resulted in significant increase in amounts of all the test constitutional, enzymatic and nonenzymatic biochemicals in the test genotypes, however their percent increase was highly variable across genotypes. These studies demonstrate that both constitutive and C. partellus damage induced enzymatic and nonenzymatic antioxidants like APX, AO, PAL, TAL, CAT, total phenols and FRAP were significantly greater in IS 2205, IS 18,551, ICSV 1, ICSV 700 and ICSV 93,046 than in susceptible check (Swarna) indicating their role in plant defense. Furthermore, these genotypes can be used in sorghum breeding for resistance against C. partellus.