Induction of chitinases and β-1,3-glucanases in resistant and susceptible cultivars of sorghum in response to insect attack, fungal infection and wounding

Abstract

Sorghum genotypes that differ in their resistance to the fungus, Fusarium moniliforme or aphids were analyzed for their response to stress induced by infection with the fungus, by feeding injury due to insect pests, or by mechanical wounding. The pathogenesis-related (PR) proteins, chitinases and β-1,3-glucanases, were induced in the plant tissues in all inbreds under all three stress conditions. However, there were differences in the responses of the individual inbreds and in the extent and duration of the induction of these enzymes by the three stress conditions. In general, both susceptible and resistant inbreds had higher levels of the enzymes especially at late times after exposure to the insects. The induced enzyme activities were found in the apoplastic space and intracellular locations, but the distribution varied depending on the genotype and the stress employed.