Heat Tolerance Was Identification In Wheats And Cloning, Expression Of HSP From Wheat

The relative conductivity and heatshock protein mRNA relatively expressing of 15 wheat varieties from Huanghuai wheat growing areas were studied . Five varieties ,yumai 18,zhoumai19,yanzhan 4110 , yumai 49-198 and china spring, were evidently higher than others in their heat tolerance. The effects of heat stress on protein oxidation carboxide, protective enzymes, MDA content,and relative water content of those five varieties were tested. And the mechanism of high temperature endurance of wheat was discussed. HSP gene cDNA, named TaHSP16.9 (GenBank accession number EU649679) was cloned from Wheat by RT-PCR amplification and the expression of TaHSP16.9 was researched. The results were as follows.1.The heat-resistant identification of wheat varieties under high temperature stress1) Among the 15 cultivars,the heat-tolerance of Zhoumai 19,Yumai 49-198,Yanzhan 4110,Pingan 3, Fumai 936 and Yumai 49 were highest in the booting stage and China spring ,Zhoumai 16, Yumai 18 ,Yumai 34,Yunong 301 were relatively lower.2) Relative conductivities of 15 wheat varieties under 49±1℃stress were not significant. 2 hours 40℃heat stress can increase the heat resistance of wheat and reduce the relative conductivity of leaves,improve wheat heat stress tolerance. Heat-resistant varieties,Yumai 49-198, Yanzhan4110 , Xiaoyan 81,Yumai 49 and Zhoumai 16 were the higher than Others in heat-resistance.3) Under high temperature stress, the protein oxidation carboxide of heat resistance of wheats was lower significantly than that of heat-sensitive varieties.It showed that the damages to plasma membrane of heat-tolerant wheat varieties were not serious, the activity of SOD and CAT and relative water content of heat-tolerant varieties were significantly higher than that in Chinese Spring and yumai 18,but their POD activity was lower.2 Clone and expression of TaHSP16.9 cDNA from WheatUsing maize low molecular weight heat shock protein (GenBank accession No. CAA46641) amino acid sequence as a, many highly homologous EST sequences were obtained from GenBank and a putative cDNA sequence of wheat (Triticum aestivum) was assembled. Futhermore, a wheat 16.9 kDa HSP gene cDNA, named TaHSP16.9 (GenBank accession number EU649679) was cloned. TaHSP16.9 was 756 bp in full length, including 5' untranslated region of 82 bp,3' untranslated region of 218 bp, and an open reading frame (ORF) encoding 151 amino acid. Homology analysis showed that the deduced amino acid sequence of TaHSP16.9 shared 78.3%～96.7% identity with 16.9 kDa HSP from other monocotyledon. The TaHSP16.9 was expressed in mature wheat stems, immature spikes and immature leaves and TaHSP16.9 expression was up-regulated by heat shock in wheat seedlings by quantitative RT-PCR.