三个苹果NBS基因的鉴定及其对外源生长物质的响应

Identif ication of Three Apple NBS Genes and Their Expression Responding to Exogenous Phytohormones

为了探讨苹果NBS基因的生理作用,从苹果中鉴定了NBS家族的3个基因,分别命名为MdNBS、MdTIR-NBS1和MdTIR-NBS-LRR1。这3个基因编码的蛋白质均含有NB-ARC结构域,MdTIR-NBS1和MdTIR-NBS-LRR1蛋白N端还有TIR结构域,MdTIR-NBS-LRR1蛋白在C端含有LRR结构。荧光定量PCR分析表明,这3个不同类型的NBS基因的表达具有明显不同的组织特异性,此外,MdNBS、MdTIR-NBS1和MdTIR-NBS-LRR1在‘嘎啦’苹果幼苗叶片中均受SA和MeJA诱导。ACC处理不能提高MdNBS和MdTIR-NBS1基因的表达,但能诱导MdTIR-NBS-LRR1基因表达。结果表明,MdNBS、MdTIR-NBS1和MdTIR-NBS-LRR1基因可能参与了苹果抗逆或抗病防御反应。

To explore the physiological roles of apple NBS genes,three typical NBS genes were identified from Malus×domestica and designated as MdNBS,MdTIR-NBS1 and MdTIR-NBS-LRR1.All the proteins encoded by the three genes contain a NB-ARC domain.In addition,both MdTIR-NBS1 and MdTIR-NBS-LRR1 proteins include a TIR motif in N terminus and MdTIR-NBS-LRR1 protein has a LRR motif in C terminus.The quantitative real-time PCR revealed that the expressions of these three NBS genes varied with different organs.MdNBS was highly expressed in functional leaves,MdTIR-NBS1 in buds and MdTIR-NBS-LRR1 in young leaves,respectively.Expression course analysis demonstrated that the expression of MdNBS,MdTIR-NBS1 and MdTIR-NBS-LRR1 in the young leaves of ‘Gala’ apple could be up-regulated by SA and MeJA.ACC treatment could not enhance the expression of MdNBS and MdTIR-NBS1,but could promote the expression of MdTIRNBS-LRR1.Taken together,the results implied that the three genes might be involved in defense responses against biostress or abiostress in apple.