Rice Plant’s High Temperature Identification Of Rice Variety HT54and Function Analysis Of Candidate Gene OsHTAS For High Temperature Resistance

With the rapid development of global economy and carbon dioxide emissions increasing year by year, the high temperature thermal damage happened frequency is more and more frequent, leads to large crop production and product quality decline when it is serious. In the face of such cultivation adversity, how to stabilize and increase crop yield, and ensure the agricultural economy and food security, has become the urgent need to solve significant scientific research topics of the agricultural science and technology field. Rice is one of the most important food crops,and which is the staple food for more than half of the population of the global. Therefore, under the background of the average global temperature is rising year by year, our urgent need is to solve the problem of high temperature resistant rice, which has a very important significance to our country food safety and agricultural sustainable development.The plant materials used in the present study include hybrid F2, HT54. a heat tolerance cultivar, and HT13, a heat sensitive cultivar, which were provided and identified by Xuhua Zhong a research fellow from Rice Research Institute of Guangdong Academy of Agricultural Science. We attempted to establish suitable high temperature resistance evaluation procedures as well as its assesment criteria at late stage, and on this basis, to further analyse the relevance of characteristics of resistance to high temperature between seedling stage and late stage for rice plants. Gene OsHTAS is a candidate gene for resistance high temperature that was determined by conducting inheritance analysis and gene mapping of high temperature resistance present in HT54carried out in our laboratory(Dr. Wei he’s thesis,2011). The present study used this gene as investigation object to go for expression analyses and functional confirmation based on morden biology means. The main results and conclusions obtained were as follows:1. Rice plant’s high temperature identification at late stage:we regard rice seed setting rate have given temperature processed as identification index of characteristic of resistance to high temperature for rice plants at late stage. HT54and HT13, parental control material MH63, Jane indica97, two optimal0293, all of them were cultivated under net house by soil until anthesis, and then were removed into growth cabinet and treated by38℃,39℃,40℃,41℃,42℃,45℃for6hours. Control plants are remained in the net house at room temperature. To identify spikelets exposed to both high and control temperature,anthesing spikelets were marked with acrylic paint after high temperature treatment. The results showed that rice setting rate decline gradually with the temperature increasing under high temperature treatment, compared to the control plants.at the same time, the setting rate of HT54declined minimum and stayed above70%under38℃high temperature treatment.Among them,the biggest decline of setting rate is HT13, dropped from92.6%to12.8%. According to these results,we think that HT54has the characteristics of resistance to high temperature at late stage.and we established the high temperature procedures at late stage:rice plants are cultivated under net house by soil until anthesis,6h38℃high temperature treatment with75%air relative humidity, setting rate is up to70%after treatment as the appraisal indicators.2. the relevance analysis of characteristic of resistance to high temperature between seedling stage and late stage for rice plants:hybrid F2generation material for HT54and HT13, was cultivated under net house by soil until anthesis. and then were removed into growth cabinet and treated by38℃.39℃high temperature treatment,andcalculating their setting rate.At the same time we identified gene type of F2generation rice plants.Comparing genetype with phenotype identification resalt. The results showed that we can’t judge whether there is relewance in characteristic of resistance to high temperature between seedling stage and late stage for HT54or not.3. Function analysis of gene OsHTAS:In the cellular localization experiments, OsHTAS:YFP was localized to the cell membrane indicating that the product of OsHTAS gene is a kind of membrane protein; In semi-quantitative interpretation experiments, at6hours processing time point,we found OsHTAS gene expression quantity increasing for HT54and decreasing for HT13. Gene OsHTAS is a Zinc finger protein gene that was determined by gene mapping of high temperature resistance present in HT54carried out in our laboratory(Dr. Wei he’s thesis,2011).At the same time, the results of this study and zinc finger protein gene characteristics are consistent.In OsHTAS gene’s transformation of yeast cell experiments,after50℃Cheat treatment,we found that the restoring growth ability of the yeast for transformating OsHTAS gene more strong than the control yeast,which preliminarily confirmed that gene OsHTAS help cells resist high temperature stress damage.In conclusion, this study identified the characteristic of resistance to high temperature from the agronomic characters,and analyses the biology function of gene OsHTAS from the molecular level.