转外源Trxs基因大麦耐盐性有关生理生化特性分析

Effects of Exogenous Trxs on Physiological and Biochemical Characteristics of Salt Tolerance in Transgenic Barley Seedlings

以过量表达硫氧还蛋白s基因(Trxs)的转基因大麦株系(LSY-11-1-1)及其非转基因对照(CK)为试验材料,研究了50mmol/L盐胁迫条件下,Trxs过量表达对大麦幼苗耐盐性有关生理生化特性的影响。结果显示:盐胁迫下转基因大麦的鲜重与干重高于对照,而丙二醛(MDA)与羰基含量低于对照。盐胁迫下转基因大麦幼苗叶片的过氧化物歧化酶(SOD)活性与过氧化氢酶(CAT)活性普遍高于对照。转基因大麦类囊体中铁蛋白大量积累的持续时间比对照长。由此可以推测,Trxs至少可以通过两条途径缓解盐胁迫对大麦幼苗生长的抑制作用:一方面增强抗氧化酶活性、有效清除过量产生的活性氧;另一方面能促进铁蛋白含量的增加、抑制Fenton反应来减少活性氧的过量产生,从而赋予转基因大麦幼苗更强的抗盐胁迫能力。

A barley variety, LSY （CK）, and its transgenic line with over-expressing Trxs （LSY-11-1-1）were used to investigate effects of Trxs on physiological and biochemical characteristics of barley seedlings under 50 mmol/ L NaCl stress. The results showed that the damage degree caused by salt stress in the transgenic barley seedlings was much less than CK as reflected by higher fresh weight and dry weight, and lower contents of malonaldehyde and protein carbonyl in the transgenic line. In comparison with CK, activities of superoxide dismutase （SOD） and catalase （CAT） in the transgenic barley leaves were generally higher. Overexpressing Trxs increased accumulation of ferritin at the protein level in the thylakoid since the accumulation of ferritin lasted longer time in LSY-11-1-1. These results suggested that Trxs could effectively protect barley seedlings from salt stress damage by enhancing activities of antioxidant enzymes to quench the excessive reactive oxygen species （ROS）caused by salt stress and inducing the increase of ferritin accumulation to decrease the ROS production by the means of inhibiting the Fenton reaction.