Expression Of The Function Genes And Physiological Indicaters Analysis Induced By Drought Stress In Various Wheat(Triticum Aestivum L.)

Drought stress is one of the major environmental limitation that severely affects plant growth and crop productivity. Wheat as a major cereals in the north of china, it is growth and productivity were subjected to the drought stress. Plants respond and adapt to drought-stress through expression of numerous genes associated with stress-tolerance. So it is very useful to study the physiological mechanism of drought tolerance and identify cultivars droughtresistance capability. In this study, four different genotypes of wheat lines(drought-tolerant wheat cultivar Pu Bing9946 and Yun Han805; drought-sensitive wheat cultivar Zhong Mai895 and Xi Nong979) were studied under drought stress(induced by 20% PEG-6000), therefore two-week days seedling of wheat were sampled in drought stress from tolerant variety and susceptible line. Real-time quantitative PCR(RT-PCR) was used to detect relative expression levels of Ta LTP1,Ta EXPB23,Ta AQP7 and Ta6-SFT in different varieties of wheat. In addition, relative water content(RWC) 、 fructan concentration and membrane permeability were analyzed at the same time. Correlation between the expression level of four function genes and physiologies were studied under drought stress. And then screen function genes as indexes of wheat drought resistance identification, enrich and complement the current wheat drought resistance identification system. The results show:(1) The expression levels of four function genes(TaLTP1,TaEXPB23,TaAQP7 and Ta6-SFT) increase notably at an early stage and then decreased at later time points, however, the expression levels of four genes in two drought-tolerant wheat cultivar were always higher than that in two drought-sensitive wheat cultivar under drought stress condition. The results suggest that those four function genes probably played a role in drought tolerance in wheat.(2) The fructan concentration and the relative electrolyte leakage were reduced under drought stress in four wheat lines, the drought-tolerant wheat cultivar had higher fructan concentration and lower relative electrolyte leakage. The RWC were also estimated and the drought-tolerant wheat cultivar had lower rates of water loss compared with the drought-sensitive wheat cultivar. These results indicate that drought-tolerant wheat cultivar had higher osmotic tolerance、retain better water status than drought-sensitive wheat cultivar under drought stress condition.(3) The results suggest that those four function genes confers drought stress tolerance in plants by changing physiological evidence. In addition, the drought-tolerant wheat cultivar had higher fructan concentration 、lower relative electrolyte leakage and lower membrane injury than the drought-sensitive wheat cultivar when they were in the same water status under drought stress. Four function genes probably played a role in drought tolerance in wheat. The expression levels of four function genes could be appraisal indices of drought-tolerance of wheat. This study provides a good identification index for cultivar drought-resistance.