| Wheat is the most important part of food crops in China,which plays a very important role in Chinese food security.According to the worldwide data survey,among the causes of wheat yield reduction,the wheat yield reduction caused by drought has far exceeded the sum of wheat yield reduction caused by other environmental disasters.In the process of implementing agricultural sustainable development strategy in China,it is necessary to improve the conversion rate of agricultural resources by using the support of drought resistance and stress resistance theory of wheat.Drought tolerance of wheat is one of the important indexes to measure the production capacity of wheat,which can accurately show the growth state and yield of wheat.Therefore,it is of great significance to clarify the response mechanism of wheat under drought stress,study the correlation between the physiological and biochemical indexes of wheat after drought treatment and drought-related transcription factors,and improve the yield of wheat in arid climate and enrich the current drought resistance identification system of wheat.In this experiment,three drought-tolerant wheat varieties Emai18,CA1090 and Jing411 under drought stress were determined.Three drought-sensitive wheat varieties Yumai57,Zhongyu5 and BRUTA;Three kinds of drought tolerance wheat varieties Xiaoyan6,CA1055 and Fr03711,a total of 9 different drought resistance wheat leaves relative water content,MDA,soluble protein,soluble sugar four physiological and biochemical indexes after 72 h of drought stress changes,at the same time through the detection of9 different varieties of wheat Ta NAC2,Tab ZIP15 and Ta SIM gene expression,and through the analysis of the relative changes of wheat physiological indexes and Ta NAC2,Tab ZIP15 and Ta SIM gene expression correlation,discusses the transcription factor Ta NAC2,Tab ZIP15 and Ta SIM become the feasibility of wheat drought tolerance identification index,hoping to expand the identification system of plant resistance,provide a reference for wheat yield under arid climate.The results are as follows :(1)After 72 h of drought stress,four physiological and biochemical indexes showed that drought tolerant wheat had stronger response to drought stress.The contents of soluble protein and soluble sugar in wheat varieties with different drought resistance were significantly higher than those in the control group,and the growth rate of drought tolerant wheat was significantly higher than that of drought sensitive wheat.Compared with the control group,the relative water content decreased significantly after drought stress,and the decrease of leaf relative water content in drought sensitive wheat was greater than that in drought tolerant wheat.After drought stress,the MDA content was higher than that in the control group,and the growth rate of drought-sensitive wheat was higher than that of drought-tolerant wheat.Emai18,a drought tolerant variety,is most consistent with this rule,so its drought resistance is stronger.The correlation analysis showed that the relative changes of soluble protein and soluble sugar were negatively correlated with the relative changes of MDA,and significantly positively correlated with the relative changes of relative water content.The relative changes of soluble protein and soluble sugar were significantly positively correlated.(2)After 72 h of drought stress,the change of transcription factor expression showed that Ta NAC2,Tab ZIP15 and Ta SIM genes were involved in the response of nine wheat cultivars to drought stress.The expression levels of # three genes in drought-sensitive varieties were lower than those in drought-tolerant varieties.The expression levels of Ta NAC2 and Tab ZIP15 genes were the highest in Emai18,and the lowest in wheat Zhongyu5.This indicated that these three wheat varieties with high gene expression had strong ability to resist drought and could be used as drought tolerance index.(3)The expression levels of Ta NAC2,Tab ZIP15 and Ta SIM genes were significantly negatively correlated with MDA,and significantly positively correlated with relative water content,soluble protein and soluble sugar under drought stress,which further indicated that the three transcription factors played a positive regulatory role in wheat drought stress response,involved in the regulation of reactive oxygen species scavenging to protect the cell membrane,and also involved in regulating the accumulation of osmotic adjustment substances such as soluble protein and soluble sugar to improve drought tolerance.It also showed that there were differences in the regulation of Ta NAC2,Tab ZIP15 and Ta SIM gene expression in wheat varieties with different resistance. |
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