| Stripe rust, caused by Puccinia striiformis f. sp. tritici, is one of the most serious diseases of wheat in the worldwide, and planting resistant cultivars is the most effective and economical methods to control this disease. However, Because single cultivars are planting widely and resistance gene are overcome by new pathtype of Puccinia striiformis f. sp. tritici for several years, The resistance cultivar"breakdown"theirs resistance. So the research of cultivars resistance were received more and more closed attention. High-temperature induced resistance is a durable, non-race specific, all stages resistance in a relative high temperature; it is becoming focus for many researchers.In the research, two races of stripe rust CY30 and CY31 were used. Firstly, Analyze resistance on several cultivars under relative high temperature. Secondly, Study on the genetic rule, analyze and map the resistance genes. Subsequencely, In order to find the correlativity between the high temperature resistance and the expression of the chitinase gene Chi1, Semi-RT PCR is applied to acquire the expression profiles of chitinase gene in stripe rust-infected leaves of Xiaoyan54, which are raised under normal (10±1~14±1℃) and high (15±1~21±1℃) temperature at the different stages.The result showed as follows:1.Resistance test demonstrated that common wheat cultivars Xiaoyan54, Xiaoyan81 and Jing411 possessed apparent resistance to stripe rust CY30 and CY31 under high temperature treatment.2.With the common wheat cultivars Xiaoyan54 and Jing411, as well as a population of 107 recombinant inbred lines generated from a cross between them as materials in our experiments. The results of QTL mapping the high temperature resistance gene to stripe rust are as follows:(1) There are two QTLs of the resistant genes to stripe-rust in the cultivar Xiaoyan54, and they were mapped on chromosomes 1BL (QYrxy1B) and 7B (QYrxy7B), contributing 6.25-16.65% and 7.05-12.1% to the phenotypic variance, respectively.(2) There are three QTLs of the resistant genes to stripe-rust in the cultivar Jing411, and they are located on chromosomes 2B (QYrxy2B),3D (QYrxy3D) and 7D (QYrxy7D), contributing 7.35-12.5%, 7.875-13.8% and 7.65-15.9% to the phenotypic variance, respectively.3.To investigate the correlativity between high temperature-induced resistance and expression of Chi1 in Xiaoyan 54, we isolated the full length cDNA of Chi1 coding region from Xiaoyan54 by RT-PCR, named temporarily as Chi1xy. We further analyzed the expression profiles of Chi1xy in Xiaoyan54 seedlings which were infected with CY30 and grew under high (15±1~21±1℃) and normal (10±1~14±1℃) temperature conditions, respectively, by Semi-quantitative RT-PCR. The expression profiles showed that, in normal temperature condition, the expression of the Chi1xy was kept at low level, similar to control non-inoculated seedlings throughout the experimental period (up to 192 hours after treatment). Whereas in high temperature treatment group, the expression of the Chi1xy was kept at low level, similar to normal temperature treatment group, till 72h, then the expression level of Chi1xy was up-regulated remarkably from 96 to 192 h, and showed an expression peak at 144 h after high temperature treatment. This notable difference of the expression profiles in these two temperature treatments suggested that expression level of the Chi1xy correlate with high temperature-induced resistance to stripe rust in Xiaoyan54.In this study, the correlativity between high temperature-induced resistance to stripe rust and chintinase gene expression was reported first time in common wheat. Our data provided a new clue for further investigating the genetic mechanism of high temperature-induced resistance to stripe rust in wheat in the future. |
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