大豆转录因子GmMYC2L参与植物耐盐性调控

Soybean transcription factor GmMYC2L is involved in the regulation of plant salt tolerance

转录因子在植物应对逆境胁迫的响应和调节过程中起着十分重要的作用。为探究大豆bHLH转录因子家族成员GmMYC2L在植物耐盐胁迫中的功能,本研究利用序列同源比对分析大豆GmMYC2L蛋白与三裂叶薯、番茄、芝麻、本氏烟草和拟南芥MYC2蛋白的保守结构域,利用半定量PCR检测盐胁迫对大豆GmMYC2L基因表达模式的诱导作用,通过烟草叶片瞬时表达分析GmMYC2L蛋白的亚细胞定位,利用浸花法获得转GmMYC2L基因拟南芥植株,并分析野生型和转基因拟南芥植株对盐胁迫的响应及机制。结果表明,大豆GmMYC2L蛋白具有bHLH家族典型的保守结构域且定位于细胞核;盐胁迫下,大豆根和叶中GmMYC2L基因表达量明显上调。盐胁迫下,GmMYC2L基因过表达拟南芥植株叶片中丙二醛含量和过氧化氢含量显著低于野生型拟南芥植株,叶片中超氧化物歧化酶(SOD)活性和过氧化物酶(POD)活性显著增加;抗氧化酶基因AtSOD和AtPOD的相对表达量亦显著上调。以上结果说明大豆GmMYC2L基因能通过抗氧化途径增强植物的耐盐性。本研究结果为大豆等作物的耐盐性遗传改良提供候选基因。

Transcription factors play an important role in the response and regulation of plants to adversity stress.In order to explore the function of soybean bHLH transcription factor family member GmMYC2L in plant salt tolerance,the conserved domains of soybean GmMYC2L protein and MYC2 proteins of sweet potato,tomato,sesame,Nicotiana benthamiana and Arabidopsis thaliana were analyzed by sequence homology comparison.The expression pattern of soybean GmMYC2L gene induced by salt stress was detected by semi-quantitative PCR.The subcellular localization of GmMYC2L protein was analyzed by transient expression in tobacco leaves.GmMYC2L gene transgenic Arabidopsis thaliana plants were obtained by floral dip method.The response and mechanism of wild-type and transgenic Arabidopsis thaliana plants to salt stress were analyzed.The results showed that soybean GmMYC2L protein had a typical conserved domain of the bHLH family and the protein was localized in the nucleus.Under salt stress,the expression of GmMYC2L gene in soybean roots and leaves was significantly up-regulated.Under salt stress,the contents of malondialdehyde and hydrogen peroxide in the leaves of GmMYC2L overexpressing Arabidopsis thaliana plants were significantly lower than those of wild-type Arabidopsis thaliana plants,and the superoxide dismutase(SOD)activity and peroxidase(POD)activity in the leaves were significantly increased.The relative expression levels of antioxidant enzyme genes AtSOD and AtPOD were also significantly up-regulated.The above results indicated that soybean GmMYC2L gene could enhance salt tolerance of plants through antioxidant pathway.The results of this study provide candidate genes for genetic improvement of salt tolerance in soybean and other crops.