Root enzyme activities associated with resistance to Heterodera avenae conferred by gene Cre7 in a wheat/Aegilops triuncialis introgression line.

The effect of Cereal cyst nematode (Heterodera avenae) infection on the expression of putative root defence-related enzymes, peroxidase (PER), esterase (EST) and superoxide dismutase (SOD), was studied in roots of a wheat/Aegilops triuncialis introgression line TR-3531 carrying the Cre7 resistance gene. We analysed detoxificant isozyme changes within roots of the resistant line and their susceptible parent (H-10-15) as a control, during the early interaction with the pathotype Ha71 of H. avenae. Isoelectrofocusing (IEF) isozyme analysis, four and seven days after infection, revealed that PER, EST and SOD activities increased in the resistant line TR-3531 in comparison with the susceptible control. Moreover, four and seven days after infection, the TR-3531 line showed the expression of new PER isozymes, with pIs of 9.7, 9.0, 8.5, 6.5 and 5.0, and an increased activity of some constitutive isoforms. The intensity of some EST and SOD constitutive bands increased in the resistant line after infection. However, no new isoforms were detected for EST and SOD systems. Nematode-induced enzyme activity was minor (PER) or did not occur (EST and SOD) in the compatible interaction with H-10-15. The enhanced peroxidase and esterase activities may play a role in the lignification of cell walls, which assists in the resistance to penetration by the nematode.