两个大豆GmSBP基因的特征、亚细胞定位及对非生物胁迫的响应

Characterization and subcellular localization of two SBP genes and their response to abiotic stress in soybean (Glycine max (L.) Merr.)

摘要:

我国南方春大豆种子发育过程中，常处于高温、高湿季节，加之种子本身富含蛋白 (约40%) 和脂肪 (约20%)，导致南方春大豆种子易劣变。本项目组前期差异蛋白质组学研究发现蔗糖结合蛋白在高温高湿胁迫168 h时在种子田间劣变抗性品种湘豆3号发育种子中呈下调表达。为进一步从分子水平了解GmSBP基因表达以及响应高温高湿胁迫的特性，本研究利用RT-PCR技术从大豆扩增出两个GmSBP基因(GmSBP2和GmSBPL)。两个基因编码的蛋白均为亲水性，不完整的膜蛋白。荧光定量PCR分析表明：在高温高湿条件下，种子田间劣变不抗品种宁镇1号和抗性品种湘豆3号发育种子中 GmSBP2和GmSBPL基因表达量均受高温高湿胁迫影响，也会导致种子中蔗糖和可溶性糖含量变化。在籽粒发育过程中，GmSBP2和GmSBPL基因表达量在花后30 d左右达到最高，对应时期的蔗糖和可溶性糖含量也达到最大值。组织特异性显示GmSBP和GmSBPL基因在不同组织间存在差异表达。亚细胞定位结果表明GmSBP2和GmSBPL蛋白均定位在细胞膜和细胞质中。以上结果表明GmSBP2和GmSBPL基因可能参与了植物非生物胁迫的应答过程，这将从一个侧面丰富我们对大豆种子田间劣变性和劣变抗性的认识。

Abstract:

High temperature and humidity stress during seed growth and development of spring soybean can result in seed deterioration in South China. We isolated two genes (GmSBP and GmSBPL) encoding putative SBP proteins from soybean (Glycine max (L.) Merr.) to study their biological functions and response to abiotic stress,. The two SBP proteins are hydrophilic and incomplete membrane ones. Real-time quantitative (RT-PCR) analysis reveals that the expression of the two genes in the developing seeds of the seed deterioration resistant cultivar Xiangdou No. 3 and sensitive cultivar Ningzhen No. 1 was significantly affected by high temperature and humidity treatment. Meanwhile, the levels of sucrose and soluble sugar in the developing seeds of both cultivars were also affected under high temperature and humidity stress. During seed growth and development, the expression of the two genes as well as the levels of sucrose and soluble sugar reached the highest at 30 days after flower. GmSBP2 and GmSBPL were found to be differentially expressed in different soybean tissues. Sub-cellular localization indicated that two genes were located in cytoplasm and cell membrane. Our results indicate that GmSBP2 and GmSBPL might be involved in the response to abiotic stress, which will enrich our understanding of pre-harvest seed deterioration and resistance in soybean from one side.