GsERF6基因过表达对水稻耐盐碱性的影响

Effects of GsERF6 overexpression on salt-alkaline tolerance in rice

乙烯响应因子(ERF)是植物特有的一类转录因子,在响应非生物胁迫中具有重要作用。本研究通过生物信息学发现,野生大豆耐盐碱ERF转录因子GsERF6与水稻ERF同源蛋白的氨基酸序列相似性很高,均包含1个高度保守的AP2结构域。为探究GsERF6基因在水稻耐盐碱应答中的作用,通过遗传转化、PCR和半定量RT-PCR鉴定,获得了2个纯合的GsERF6过表达转基因水稻株系。表型鉴定表明,200 mmol L^(-1) NaHCO3处理下GsERF6转基因水稻的存活率、相对含水量、超氧化物歧化酶、过氧化物酶、过氧化氢酶活性、可溶性糖和脯氨酸含量均显著高于对照,活性氧积累则反之。实时荧光定量PCR分析表明,40 mmol L^(-1) NaHCO3处理6 h后渗透调节基因OsP5CS2和OsLEA14在GsERF6转基因水稻中的表达量显著高于对照。本研究表明,水稻中GsERF6的过表达可通过提高ROS清除水平、渗透调节能力及胁迫应答基因的表达来提高其耐盐碱性。

Ethylene response factors(ERFs)are a family of plant specific transcription factors that play important roles in abiotic stress.Bioinformatic analysis revealed that GsERF6,a Glycine soja ERF transcription factor that positively regulated salt-alkaline tolerance,shared high sequence identity with homologous ERF proteins with one highly conserved AP2 domain in rice.To explore the effect of GsERF6 overexpression on the salt-alkaline tolerance in rice,we transformed GsERF6 into rice and obtained two homozygous transgenic lines via PCR and RT-PCR.Phenotypical and physiological assays indicated that,compared with the wild type rice under 200 mmol L^(-1) NaHCO3 treatment,the survival rate,relative water content,the activities of SOD,POD,and CAT,the soluble sugar and proline contents,were significantly increased,while ROS accumulation was significantly decreased in GsERF6 overexpression lines.The qRT-PCR showed that transcript levels of OsP5CS2 and OsLEA14 were significantly up-regulated in GsERF6 transgenic line after 40 mmol L^(-1) NaHCO_(3) treatment for 6 hours.In summary,GsERF6 overexpression in rice contributed to ROS scavenging,osmotic regulation,and activation of stress responsive genes,thus improving the salt-alkaline tolerance of transgenic rice.