水稻永绿色基因超表达和突变对其叶片氮碳代谢若干指标的影响

通过水培实验,研究了水稻永绿色(Stay-green rice,SGR)基因超表达和突变对叶片氮碳代谢的影响。结果表明,在正常生长条件下,SGR基因超表达降低了水稻叶片可溶性蛋白、叶绿素及淀粉的含量,但可溶性糖和游离氨基酸含量增加,并提高了谷氨酰胺合成酶(GS)活性和谷氨酸合成酶(GOGAT)活性;SGR基因突变增加了水稻叶片淀粉和可溶性蛋白质含量,并提高了硝酸还原酶(NR)活性。在缺氮条件下,SGR基因超表达与野生型叶片各生理指标的变化趋势一致,但是SGR基因突变体叶片中淀粉含量的变化趋势与野生型及SGR基因超表达的不一致。这说明SGR蛋白水平的变化在一定程度上影响了水稻叶片的氮碳代谢。

Effects of Stay-green Rice Gene (SGR) Over-expression and Mutation on Some Indexes Related with Carbon and Nitrogen Metabolism in Rice Leaves

The effects of Stay-green rice gene (SGR) over-expression and mutation on carbon and nitrogen metabolism in rice (Oryza sativa L.) leaves were studied by using hydroponic culture. The results showed that SGR over-expression reduced contents of soluble protein, chlorophyll and starch, but the contents of soluble sugar and free amino acids increased, as well as the activities of glutamine synthetase (GS) and glutamate synthetase (GOGAT) in rice leaves under normal growth condition. Whereas, SGR mutation increased the contents of starch and soluble protein and improved nitrate reductase (NR) activity. Under nitrogen deficiency, the variation trend of physiological parameters was consistent among the three types of rice except the starch content in SGR mutant rice leaves. These suggested that the changes in SGR level could influence the carbon and nitrogen metabolism in rice leaves.