Relationship Between Chito-oligosaccharide Induced Disease Resistance And ABA Signaling Pathway In Populus Tomentosa

Populus L. is an important tree species for afforestation, farmland protection and timber.But it is afflicted by many kinds of plant diseases. The use of chemical pesticides is aneffective way to protect trees. However, it brings a series of environment pollution problemsat the same time. In recent years, a new approach to the prevention and cure of plant diseaseshas been opened by the research on plant induced disease resistance. And it has been foundthat oligosaccharides are a type of effective elicitor.In this study, Number85clonal Populus tomentosa was used as the research object. Therelationship between chito-oligosaccharide induced disease resistance and ABA signalingpathway in Populus tomentosa was explored with the method of Bioinformatics andReal-Time quantitative PCR. This study provides a new idea for further revealing molecularmechanisms of plant disease resistance induced by chito-oligosaccharides and doing researchon plant disease resistance.The research results are as follows:1) Via BLASTP,14PtPYR,7PtPP2C and4PtSnRK2genes were obtained in Populustrichocarpa. They are homologous to Arabidopsis AtPYR, AtPP2C and AtSnRK2genes,respectively.2) Through phylogenetic analysis, it is shown that: PtPYRL9, PtPYRL10, PtPYRL11,PtPYRL12, PtPYRL13and PtPYRL14belong to ABA receptor I subfamily; PtPYRL5,PtPYRL6, PtPYRL7and PtPYRL8belong to ABA receptor II subfamily; PtPYRL1,PtPYRL2, PtPYRL3and PtPYRL4belong to ABA receptor III subfamily; PtABI1,PtAHG1, PtHAB2, PtHAI3and PtPP2CA belong to PP2C A subfamily; PtAP2C1andPtPP2C5belong to PP2C B subfamily; PtSnRK2.3and PtSnRK2.6belong to SnRK2III subgroup; PtSnRK2.7and PtSnRK2.8belong to SnRK2II subgroup.3) Based on phylogenetic analysis, PtPYRL7, PtPYRL9, PtHAB2, PtPP2CA, PtSnRK2.3and PtSnRK2.6were chosen and their primers were designed. Total RNA in Number85clonal Populus tomentosa leaves were isolated after3hour,6hour,12hour and24hour exogenous ABA treatment and chito-oligosaccharide treatment of its roots. Real-Time quantitative PCR results have shown that: the expression levels of PtPYRL7and PtPYRL9were down-regulated after ABA or chito-oligosaccharide treatment; theexpression levels of PtHAB2and PtPP2CA were up-regulated after ABA orchito-oligosaccharide treatment; the expression levels of PtSnRK2.3and PtSnRK2.6were up-regulated first and then down-regulated after ABA or chito-oligosaccharidetreatment.