Studies On Wheat Resistance Gene Analogues And Activities Of Defence Enzymes Induced By Wheat Stripe Rust Pathogens

Stripe rust, caused by the fungus Puccinia striiformis Westend f.sp. tritici Eriks.(Pst) is an important disease of wheat (Triticum aestivum L.) throughout the world. In China, especially in the southwest provinces, it is a greater threat to wheat production due to both of the favorable prevail environment for stripe rust and the simplification of cultivars and resistance genetic resources in the modern agricultural practice. Therefore, developing resistant cultivars is the most-effective way to achieve the maintainable control of the disease.In this study, wheat varieties R88, R57 and other resistant wheat varieties or lines were used for test materials. Wheat stripe rust pathogen CY32, S14 and their mixtures were used as the inoculated races. The soluble protein content, the activity of several defensive enzymes (SOD, POD and CAT) induced by rust races were investigated. Some resistance-related sequences were amplified by RGA primers and identified. Corresponding functions of several specific RGA sequences were analyzed by bioinformatics method. The results were as follows:1. The changes of defensive enzyme activity and soluble protein content induced by different types of stripe rust pathogen races were different in resistant and susceptible wheat varieties.1) Soluble protein content in the most of the resistant and susceptible varieties inoculated by both single CY32 and S14 showed a peak in 48hs, whereas it was delayed to 72hs in the case of inoculation by the mixed races.2) The activity of SOD enzyme exhibited a rising trend within 0-24hs in both the resistant varieties R88 and R57, in contrast, a decreasing trend has been seen in the susceptible varieties Sy95-71 and CS in all treatment inoculated.3) The activity of POD enzyme showed a general rise in the resistant varieties, but two peaks in the susceptible varieties in 0-96hs after inoculation .The ultimate POD level in the resistant was higher than in the susceptible. The enzyme activity change induced by the mixed races was more obvious than that done by both single race (CY32/S14). 4) The CAT enzyme activity went down sharply in 0-24hs, then a slight rise followed. R88 showed a overall higher CAT enzyme level than R57, while no evident changes of activity were observed in the susceptible varieties. The...