小麦脱落酸受体基因TaPYR1介导植株抵御干旱逆境功能研究

Functional characteristics of TaPYR1,an abscisic acid receptor family gene in mediating wheat tolerance to drought stress

脱落酸(ABA)受体PYR/PYL/RCAR通过与渗透胁迫诱导的ABA结合,参与植株体内ABA介导的信号转导过程,在调控植株干旱逆境抵御过程中具有重要的生物学功能。本文研究了鉴定的1个干旱响应的PYR家族成员TaPYR1的分子特征、应答干旱表达模式及其介导植株抵御干旱逆境的功能。结果表明,TaPYR1与植物种属中部分PYR基因在氨基酸序列水平上高度同源,编码蛋白含有PYR家族成员保守结构域,翻译蛋白经内质网分选后定位于细胞质膜。TaPYR1基因在小麦根、叶中均呈明显的干旱诱导表达模式,在干旱胁迫48 h表达量达到峰值。与野生型对照(WT)相比,超表达TaPYR1烟草转化株系,干旱处理下植株长势增强,干鲜重增加。干旱处理下,转化株系较对照的光合能力增强,细胞保护酶活性提高,渗透调节物质脯氨酸和可溶性糖含量增加。研究表明,TaPYR1通过在转录水平上应答干旱逆境,改善干旱胁迫下的植株相关生理过程,在增强植株抵御干旱逆境能力中发挥重要作用。

ABA receptors are involved in the mediation of ABA signaling transduction through interaction with abscisic acid(ABA)molecules induced by osmotic stresses and play critical roles in regulating the drought stress tolerance in plants.In this study,Ta PYR1,an ABA family gene in wheat that was shown to be differentially expressed in our previous transcriptome analysis was used to analyze its molecular property,expression patterns under drought stress condition,and functions in mediating plant adaptation to drought stress.TaPYR1 shares high similarities to its plant counterparts at amino acid level.TaPYR1 protein contains the conserved domains specified by the plant PYR proteins and was targeted onto the plasma membrane after endoplasmic reticulum(ER)assortment.The expression of TaPYR1 was induced in both roots and leaves under drought,with the highest expression levels at 48 h of drought treatment.Transgene analysis on TaPYR1 was performed to assess the gene function in mediating plant drought tolerance.Compared with wild type(WT),the tobacco lines overexpressing TaPYR1 enhanced growth vigor and increased fresh and dry weight under drought stress.In addition,the transgenic lines with TaPYR1 overexpression also increased photosynthetic function,enhanced activities of cellular antioxidant enzymes,and elevated the contents of osmolytes(i.e.,proline and soluble sugar)under drought condition.Our investigation suggests that TaPYR1 transcriptively responds to drought stress signaling and plays an important role in regulating plant drought adaptation by improving the associated physiological processes.