低聚壳聚糖诱导的毛白杨抗病反应与ABA信号通路的关系

脱落酸(ABA)信号通路核心组分有ABA受体(PYR/PYL/RCARs)、2C型蛋白磷酸酶家族中的A亚族成员(PP2Cs)以及蔗糖非酵解型蛋白激酶2家族成员(SnRK2s)。运用BLASTP序列比对方法,在毛果杨中获得14条PtPYR、7条PtPP2C和4条PtSnRK2基因,它们分别与拟南芥AtPYR、AtPP2C和AtSnRK2基因同源。根据系统进化树分析结果,选取基因PtPYRL7、PtPYRL9、PtHAB2、PtPP2CA、PtSnRK2.3和PtSnRK2.6,设计合适的引物。以85号无性系毛白杨组培苗为材料,分别对其根部进行外源ABA和低聚壳聚糖处理,于处理3h、6h、12h和24h4个时间点取样,提取样本叶片总RNA,反转录成cDNA,进行实时荧光定量PCR分析。结果显示:ABA处理和低聚壳聚糖处理均能使PtPYRL7和PtPYRL9基因表达下调,使PtHAB2和PtPP2CA基因表达上调,使PtSnRK2.3和PtSnRK2.6基因表达先上调后下调。研究表明,ABA处理和低聚壳聚糖处理诱导毛白杨叶片中与ABA信号通路相关的基因的表达变化趋势几乎一致,说明ABA信号通路是低聚壳聚糖诱导毛白杨抗病的信号传递途径之一。

Relationship between Chito-oligosaccharide Induced Disease Resistance and ABA Signaling Pathway in Populus tomentosa

The core components of abscisic acid (ABA) signal transduction in plants include ABA receptors (PYR/PYL/RCARs),group A type 2C protein phosphatases (PP2Cs) and SNF1-related protein kinases 2 (SnRK2s).In this study,via BLASTP,14 PtPYR,7 PtPP2C and 4 PtSnRK2 genes were obtained in Populus trichocarpa.They are homologous to Arabidopsis AtPYR,AtPP2C and AtSnRK2 genes,respectively.Based on phylogenetic analysis,PtPYRL7,PtPYRL9,PtHAB2,PtPP2CA,PtSnRK2.3 and PtSnRK2.6 were chosen and their primers were designed.Total RNA in Number 85 clonal Populus tomentosa leaves were isolated after 3 hour,6 hour,12 hour and 24 hour exogenous ABA treatment and chito-oligosaccharide treatment of its roots.Real-Time quantitative PCR results have shown that:(1)The expression levels of PtPYRL7 and PtPYRL9 were down-regulated after ABA or chito-oligosaccharide treatment;(2)The expression levels of PtHAB2 and PtPP2CA were up-regulated after ABA or chito-oligosaccharide treatment;(3)The expression levels of PtSnRK2.3 and PtSnRK2.6 were up-regulated first and then down-regulated after ABA or chito-oligosaccharide treatment.The study indicated that ABA signaling pathway was one of signal transduction ways of chito-oligosaccharide induced disease resistance in Populus tomentosa.