The Regulation Mechanism Of ABA Response To Zoysia Japonica Infected With Rhizoctonia Solani

In this study,transcriptome data(con pare with Rhizoctonia solani 12,24,36,48 h inoculation and un-inoculation)was used for the study of the response mechanism of ABA at the molecular level during zoysia japonica infected with brown spots.The changes of expression patterns of ABA related specific genes were analyzed by means of molecular techniques.At the same time the main resistance endogenous hormone level changes in zoysia japonica roots and leaves were detennined by plants ELISA method,and the positive or negative effects of ABA in different times during Rhizoctonia solani strain early invasion in zoysia japonica root were discussed.This research with the aim to clarify the response and the function of ABA in zoysia japonica-Rhizoctonia solani interaction,and preliminary screening of candidate functional genes and finally provides a theoretical basis for zoysia japonica resistance mechanism and breeding research.The main conclusions are as follows:1.Arranging the expression patterns of ABA related pathway genes directly reflected the mechanism of ABA responsing to the disease at the molecular level.Compared with Rhizoctonia solani 12,24,36,48 h inoculation and the control.There were 37 differentially expressed genes detected in ABA biosynthesis glycolysis pathway,up regulated gene respectively,35,36,36,37,down regulated gene respectively,1,0,1,2;there were 16 differentially expressed genes detected in terpenoid backbone biosynthesis pathway,15,16,15 and 15 genes up regulated,1,0,1 and 1 gene down regulated;there were 7 differentially expressed genes in carotenoid biosynthesis pathway,2,3,3 and 3 genes up regulated,5,4,4 and 4 gene down-regulated.The ABA signal pathway element detected 8 differentially expressed genes,respectively 3,5,3 and 4 genes up regulated,the 5,3,5 and 4 genes down regulated.There were 2 differentially expressed genes detected in ABA related transcription factors,respectively 2,2,1 and 0 genes up regulated,and 0,0,1 and 2 genes down regulated.2.Specific functional gene screening:7 candidate functional genes were selected in the ABA biosynthesis pathway,named ZjPK1,ZjPK2,ZjDXS1,ZjGGPS1,ZjBCH1,ZjNCEDl and ZjABA2.1.Four candidate genes were screened in the ABA signal pathway element,named ZjPYL1,ZjPYL2,ZjPP2C1,and ZjPP2C2.Two candidate functional genes were screened in the ABA signaling transcription factor,named ZjABF1 and ZjWRKY1.All of the above gene sequences have higher similarity with other plant homologous genes through ORF Finder,and can be located in the specific location of the japonica genome.The results of fluorescence quantitative PCR test showed that the above gene expression pattern was verified with the changes of ABA hormone level,indicating that the above preliminarily screened genes could be considered as excellent candidate genes.3.In order to determine the effect of ABA in the infection process,the research have detected the level of main resistance endogenous hormoneABA,JA.SA.The results showed that after root inoculation of pathogens,ABA level slowly accumulated in 0-12 h and positively regulated the plant disease resistance.SA played a leading role,while ABA effect was positive.In 12-24 h,ABA level rapidly accumulated and positively regulated the plant disease resistance.ABA and JA were synergistic disease resistance which played a leading role.In 24-36 h,the inhibition of SA synthesis may be caused by ABA synthesis,and there is no obvious positive or negative effect of ABA regulation.In 36-48 h,ABA level decreased and the plants lost basic disease resistance.ABA negatively regulated plant disease resistance.