Spatial Distribution of Proteinase Inhibitors Among Diverse Groups of Sugarcane and Their Interaction with Sugarcane Borers

Profiling of proteinase inhibitors (PIs) was done on the diverse group of sugarcane viz., exotic clones, hybrids and Erianthus arundinaceus. Their inhibitory activity against commercial trypsin enzyme and midgut protease of sugarcane borers was investigated. Proteinase inhibitors were extracted from leaf sheath, meristem and stalk tissue of selected groups. The results revealed that the PIs were in maximum quantity in meristem followed by leaf sheath and stalk tissue of hybrids and E. arundinaceus. The trypsin inhibition was maximum in leaf sheath (11.51-32.26%), meristem (15.86-90.94%) and stalk tissue (1.62-39.62%) of E. arundinaceus compared to those of hybrids and exotic clones. Subsequently, extracted meristem and stalk tissue PIs were assayed against midgut protease of sugarcane early shoot borer (ESB) and internode borer (INB). The results showed that PIs from E. arundinaceus meristem significantly inhibited the midgut protease of ESB and INB up to >70 and >60%, respectively. However, the PI from the meristem of exotic clones and hybrids showed considerable inhibition to midgut proteases of ESB. The PIs from stalk tissue of all groups were ineffective as regards gut protease inhibition in the sugarcane borers.