Analysis On The Function Of Genes Involved In S-adenosylmethionine Metabolic Pathways To Drought Stress And Water Use Efficiency In Wheat

Water is one of the most important factors that affect crops growth and development. But Water shortage has become the serious problem to the world crop production. Drought also influences the development of agriculture production and domestic economy to our country. Wheat is a major crop in arid and semi-arid regions of our country, which is the second staple crop after rice, and has very important role in the national food production. However, the yield of wheat is low and precarious in the world for a very long time because of drought and water shortage. Therefore, in order to provide effective evidences for improvement of wheat drought resistance, it is necessary that studying the molecular basis of wheat drought resistance, investigateing genes related to drought tolerance in depth, and exploiting the technology to improve the capacity of crop drought resistance. This study used he semi-quantitative RT-PCR to investigate the expression patterns of the three genes of S-adenosylmethionine synthetase, S-adenosylmethionine decarboxylase and gamma-glutamy- lcysteine synthetase during PEG-simulated water stress and re-watering after serious water stress. BSMV-VIGS technique was also used to silence the three genes of S-adenosylmethion ine synthetase, S-adenosylmethionine decarboxylase and gamma-glutamylcysteine synthetase in order to determine their relationship with drought resistance. The main results are as follows:1. The semi-quantitative RT-PCR was used to investigate the expression patterns of the three genes of S-adenosylmethionine synthetase, S-adenosylmethionine decarboxylase and gamma-glutamylcysteine synthetase in the leaves of wheat seedling of Jinmai 47 during PEG-simulated water stress and re-watering after serious water stress. The results showed that the three genes were expressed under the normal growth condition. The expressions of SAMS and SAMDC were up-regulated at 6, 12, 24 and 48 h of PEG-6000 simulated water stress, then were down-regulated at 75 h of water stress, and were up-regulated again at 3-6 h after re-watering, decreased again after 9 h after re-watering to the normal level. The expressions ofγ-ECS were up-regulated at PEG-6000 simulated water stress, and then were down- regulated at re-watering to the normal level. The expression patterns of wheat SAMS, SAMDC andγ-ECS during water stress and re-watering after serious water stress indicated that the three genes were involved in the regulations of wheat to water stress, and SAMS and SAMDC were also involved in the recovery after re-watering. The results suggested that the SAM metabolic pathways played an important role in drought-tolerance and water use efficiency of wheat.2. BSMV-VIGS technique was used to silence the three genes of S-adenosylmethionine synthetase, S-adenosylmethionine decarboxylase and gamma-glutamylcysteine synthetase based on the sequences of Jinmai 47 in order to determine their relationship with drought resistance.The result shows that the silenced wheat plant is different from the control one concerning the morphological trait (the leaves turned curly and wilted), which implies that the silenced plant is more vulnerable to drought stress,so the function of SAMS, SAMDC andγ-ECS with drought resistance is determined preliminarily. The SAM metabolic pathways have the potential value to improve drought stress and water use efficiency.