Induction of defence related enzymes and phenols by sar chemicals and biocontrol agents against karnal bunt (Tilletia indica Mitra) of wheat

Karnal bunt (KB) or partial bunt of wheat (Tilletia indica Mitra) is a disease of quarantine importance and difficult to control as it has multiple modes of transmission. In the absence of desirable resistance, the use of systemic acquired resistance (SAR) chemicals and bio-control agents (BCAs) might be useful for its effective management. Thus, role of SAR chemicals viz. jasmonic acid, salicylic acid and bio-control agents viz. Trichoderma viride, and Pseudomonas fluorescens was studied in KB resistant (ALDAN) and susceptible (HD2967) genotypes. Foliar application of salicylic acid at 10 ppm recorded the maximum level of total phenols while maximum activity of peroxidase, phenylalanine ammonia lyase and polyphenol oxidase was found at 50 ppm. Similarly, JA at 50 ppm was found to induce peroxidase, polyphenol oxidase and phenylalanine ammonia lyase and total phenols to the maximum extent and recorded the lowest average coefficient of infection in the test genotypes ALDAN and HD 2967 among all other treatments, respectively. However, no significant difference in ACI in the test genotypes ALDAN and HD 2967 was observed with the application of JA at 50 and 100 ppm. Seed + foliar treatment with BCAs was found to be better in induction of peroxidase, polyphenol oxidase and phenylalanine ammonia lyase and total phenols as compared to seed treatment alone. These findings can be useful in understanding the biochemical basis of resistance and devising an innovative strategy for the effective management of KB.