凝集素类受体蛋白激酶属于类受体蛋白激酶(RLKs)家族,在植物的抗病防御反应、生长发育、胞内信号传导以及非生物胁迫反应过程中发挥重要作用.实验室前期对过表达抗逆转录因子GmNFYB1大豆进行转录组测序,获得了差异表达基因GmLecRlk(Glyma.07G005700),其开放阅读框长度为546 bp,编码181个氨基酸,蛋白结构域分析显示其含有两个丝氨酸/苏氨酸激酶结构域,属于一种G型凝集素类受体蛋白激酶.实时荧光定量PCR结果显示,GmLecRlk基因在大豆的根、茎、叶、荚中均有不同程度的表达,在根中表达量最高;200 mmol/LNaCl处理下,GmLecRlk的mRNA丰度先降低后升高,在12 h时达到最高值,表明该基因参与大豆对盐胁迫的响应.利用发根农杆菌K599获得GmLecRlk过表达转基因发状根复合植株,在盐胁迫处理下,其存活率高于对照;在拟南芥中异源表达GmLecRlk基因,转基因拟南芥在盐胁迫处理下的萌发率、绿化率和根长均高于野生型拟南芥.综上所述,GmLec?Rlk参与大豆对盐胁迫的反应,过量表达基因能提高大豆和拟南芥的耐盐性,为培育和改良抗盐大豆新品种提供新的途径和理论指导.

泛素化系统通过介导蛋白质的翻译后修饰,参与包括细胞分化、激素应答、生物与非生物胁迫响应等多个生物学过程,其中含有U-box基因的泛素连接酶为泛素化系统的重要酶之一.课题组前期研究发现大豆Gly?ma.13G115900(GmPUB32)基因编码一个泛素连接酶(PUB),其表达量在根中受盐胁迫影响显著.本研究在大豆品种垦丰16中克隆得到大豆U-box家族基因GmPUB32,序列分析结果表明GmPUB32基因的开放阅读框长度为513 bp,编码170个氨基酸,在其83-131个氨基酸之间含有一个RING/U-box保守结构域;亚细胞定位分析结果显示Gm?PUB32蛋白定位于细胞膜与细胞质中;GmPUB32基因在大豆根、茎、叶片与荚果中均能检测到不同程度的表达,在根中表达量最高,GUS组织化学染色进一步明确其在根中发挥主要作用;荧光定量PCR分析结果显示,在200 mmol/L NaCl处理后,与对照相比随着处理时间的延长GmPUB32在根中的表达量呈现出显著的下降趋势,表明GmPUB32可能参与大豆对于盐胁迫的应答过程;通过对过表达GmPUB32的T3拟南芥的盐胁迫耐受性进行分析,结果表明转基因拟南芥的萌发率、子叶绿化率与盐胁迫下的存活率均明显低于野生型,此外,GmPUB32过表达转基因毛状根的生长速率相比野生型也明显受到抑制.由此推断,GmPUB32可能作为负调控因子参与大豆对于盐胁迫的应答过程,降低植物对于盐胁迫的耐受性.

Plant roots absorb K+ from soil via K+ channels and transporters, which are important for stress responses. In this research, GmAKT1, an AKT1-type K+ channel, was isolated and characterized. The expression of GmAKT1 was induced by K+-starvation and salinity stresses, and it was preferentially expressed in the soybean roots. And GmAKT1 was located in the plasma membrane. As an inward K+ channel, GmAKT1 participated in K+ uptake, as well as rescued the low-K+-sensitive phenotype of the yeast mutant and Arabidopsis akt1 mutant. Overexpression of GmAKT1 significantly improved the growth of plants and increased K+ concentration, leading to lower Na+/K+ ratios in transgenic Arabidopsis and chimeric soybean plants with transgenic hairy roots. In addition, GmAKT1 overexpression resulted in significant upregulation of these ion uptake-related genes, including GmSKOR, GmsSOS1, GmHKT1, and GmNHX1. Our findings suggested that GmAKT1 plays an important part in K+ uptake under low-K+ condition, and could maintain Na+/K+ homeostasis under salt stress in Arabidopsis and soybean plants.

•Circular RNAs were identified in a whole genome in soybean.•The existence of circular RNAs were validated in cold-stressed soybean.•Circular RNAs were predicted to be involved in low temperature responses.•Circular RNAs were found to act as the sponges for miRNAs in soybean.•Circular RNAs were found to have protein-coding potential in soybean.

选用20份大豆品种,利用PEG6000模拟干旱、旱棚盆栽方式,分别统计芽期、苗期和花期发芽率、生理、叶绿素荧光等指标,收获后测定农艺性状,同时利用抗旱系数、抗旱指数、隶属值函数法综合分析抗旱性.结果 表明,不同指标或方法在大豆抗旱性鉴定中的作用存在差异,不同品种不同生育期抗旱性存在差异.综合评价全生育期抗旱性,最终筛选出3个高抗旱型品种:龙品03-311、晋豆21和艾卡166;2个抗旱型品种:绥农14和铁丰8;3个干旱敏感型品种:猫眼豆、合丰47和东农594.