StP5CS基因过表达增强高温胁迫下菜用大豆结瘤固氮的能力

Enhancement of nodulation and nitrogen fixation of vegetable soybean under high temperature stress by Overexpression of StP5CS gene

高温胁迫严重影响菜用大豆的结瘤固氮过程,增强高温胁迫下菜用大豆结瘤固氮的能力对提高菜用大豆产量具有重要意义。采用蛭石栽培的方法,以转StP5CS基因菜用大豆(T6)为试验材料,研究在35℃高温胁迫下StP5CS基因过表达对菜用大豆结瘤固氮的影响。结果显示:转基因株系的株高、干鲜重及根瘤数目、根瘤干鲜重、单株荚数、粒数、种子重均显著高于非转基因株系(WT);转基因株系根瘤中脯氨酸、豆血红蛋白含量及谷氨酰胺合成酶活性均显著高于WT;经qRT-PCR分析,5个结瘤固氮关键基因(GmENOD40-1,GmENOD40-2,GmGS1β1,GmGS1β2及GmLba)在转基因株系中的相对表达量均显著高于WT。结果表明,高温胁迫下StP5CS基因过表达,促进了脯氨酸的积累,显著增强了菜用大豆的耐热性和结瘤固氮能力,进而提高了菜用大豆的产量。

High temperature stress exerts adverse influences on the process of nodulation and nitrogen fixation of vegetable soybean. Enhancing the nitrogen fixation efficiency of vegetable soybean is of significance to increase the yield of vegetable soybean under heat stress. Using the method of vermiculite cultivation, St P5 CS transgenic vegetable soybean(T6) was used as experimental material to study the effects of St P5 CS gene overexpression on nodulation and nitrogen fixation of vegetable soybean under high temperature at 35°C. The results showed that the plant height, dry weight and fresh weight of plants, number of root nodules, dry weight and fresh weight of root nodules, number of pods and number of seeds per plant and seed weight of the transgenic lines were significantly higher than those of the wild type line(WT). Proline, leghemoglobin contents and glutamine synthetase activity in the nodules of the transgenic lines were significantly higher than those of WT. qRT-PCR analysis showed that the relative expression levels of five key genes for nodulation and nitrogen fixation(Gm ENOD40-1, Gm ENOD40-2, Gm GS1β1, Gm GS1β2 and Gm Lba) in the transgenic lines were significantly higher than those of WT. The above results indicate that under high temperature stress, overexpression of St P5 CS gene promotes the accumulation of proline, and significantly enhances the nodulation and nitrogen fixation ability, resulting in the increase of yield in vegetable soybean.