Study On The Induced Resistance Of Salicylic Acid To Wheat Stripe Rust And Genetic Mapping Of Stripe Rust Resistant Gene In Wheat (T. Aestivum L)

Stripe rust (Puccinia striiformis Westend f. sp. tritici), caused by Puccinia strriformis Westend f. sp. tritici Eriks is one of the most important disease of wheat (Triticum aestivum L.), which resulted in massive wheat yield loss in several epidemics in China. Developing and using resistant varieties is the most economic, effective and environment-friend method. On the other hand, maybe the potential defense system of plant itself could be used to limit the infection of stripe rust in wheat production.In the present study, the inducing effect of Salicylic Acid (SA) for resistance of wheat to stripe rust and the changes of enzymes activity of phenylalanine amonnia lyase (PAL), poylphenol oxidase (PPO), superoxide dismutase (SOD) and the contents of malonaldehyde (MDA) in wheat seeding leaves were investigated in durable resistance wheat cultivar of N. Strampelli and high susceptible cultivar of Mingxian169 after inoculated mixture pathogen of Puccinia striiformis f. sp .tritic. Furthermore, in order to detect resistant gene for wheat stripe rust from N. Strampelli, the F₂ population derived from the cross Mingxian169×N.Strampelli, was used to genotype and phenotype. The main results are as follows:1. The result indicated that the urediniospore germination of wheat stripe rust could not be suppressed by SA under low concentration, and the wheat seedling could be harmed as concentration of SA over 1mM. For susceptible cultivar, the resistance to stripe rust could be significantly enhanced by SA inducing within the concentration range of 0.5-1mM with an average inducing effect of 47.60%.2. The activity of defense-related enzymes and the content of MDA in wheat seedling leaves were examined after spraying SA at 0.5mM and inoculating pathogen three days later. The samples were collected on the next day, third day, fifth day seventh day, ninth day, eleventh day, thirteenth day and fifteenth day after inoculating. The result showed that the activities of PAL and PPO enhanced and the content of MDA decreased; however basically similar result was observed with CK for the activity of SOD.3. In the F₂ population derived from the cross Mingxian169×N.Strampelli, an 11 (resistant): 50 (susceptible) segregation was observed. The proportion tested byχ2 -test fitted the expected 1:3 ratio for a monogenic recessive inheritance of the trait resistance to stripe rust (χ2 = 1.60, p > 0.20). Based on the result of Bulked segregation analysis (BSA), the gene for resistance to stripe rust was located on 1BL in the near Xgwm259, and was designated Yr-Bian temporarily.