Molecular Mechanism Of Jujube Witche’s Broom Resistance Acquired From Chinese Paliurus Rootstock Mediated By The Metabolism Of ZjJAZ1、ZjPYR1-like And ZjSnRK2 In Ziziphus Jujube Mill

Ziziphus jujube is an important fruit tree in China.It can be used for both fresh food and dried fruit.It has high nutritional value and is loved by people.Jujube witche’s broom is a destructive phytoplasma disease that threatens jujube in production,and has always been an important factor affecting jujube yield and quality.There are many studies showing that the grafted jujube tree of the Chinese paliurus rootstock can not only improve the quality of the jujube fruit,but also effectively resist the damage of Jujube witche’s broom.However,the reason for the Chinese paliurus rootstock against Jujube witche’s broom has not been resolved,so the study clearly understands the copper coin.The mechanism of Chinese paliurus rootstock against Jujube witche’s broom is of great significance.On the basis of the previous research group,this study carried out transcriptome sequencing on the inoculation of healthy jujube skin and the diseased skin of jujube with different rootstocks,and performed GO enrichment analysis on the data.Secondly,the expression level of JA pathway-related genes was analyzed.The expression level of each gene in JA synthesis pathway was highest in Chinese paliurus rootstock inoculated with diseased skin.In the JA signal pathway,the expression levels of the five JAZ family genes were found to be significantly different,and they were all expressed in the Chinese paliurus rootstock inoculated with the diseased skin.Indepth study of the JAZ gene with the largest difference in expression,the results are as follows:1.The ZjJAZ1 gene was cloned and analyzed according to the NCBI database reference sequence.The full-length cDNA was 1287 bp,and the complete ORF was 792 bp,encoding 263 amino acids.Based on protein sequence alignment with other species JAZ genes,and protein structure prediction,ZjJAZ1 gene has a typical NT domain at the N-terminus,a highly conserved ZIM domain at 123-158 amino acids,and includes a TIFY motif.There is a typical Jas domain at the C-terminus;Phylogenetic tree indicates that the ZjJAZ1 gene is closely related to AtJAZ5 and AtJAZ6 in Arabidopsis.2.The overexpression vector 35S::ZjJAZ1 was constructed and transformed into Arabidopsis thaliana to obtain 3 transgenic homozygous lines(2#,3#and 4#).Compared to wild-type,ZjJAZ1 transgenic Arabidopsis showed a phenotype with early twitching and longer roots.It may be that the growth of the lower part promotes the growth of the shoots,which in turn leads to a stronger ZjJAZ1 transgenic Arabidopsis.3.After treatment with 100 mM MeJA for 24 h,the stomatal opening of the three strains of ZjJAZ1 transgenic was significantly smaller than that of wild type,and the anti-superoxide anion activity was significantly higher than that of wild type,and the hydrogen peroxide content was significantly lower than that of wild type plants.The expression levels of the resistance genes AtJAR1,AtPDF1.2,and AtNPR1 in MeJA treatment were significantly higher in WT than in WT.ZjJAZ1 transgenic Arabidopsis responds to MeJA treatment by regulating stomatal opening,reducing ROS levels,and increasing the expression level of resistance genes.4.In the PstDC3000 pathogen test,the disease on ZjJAZ1 transgenic plants was significantly lighter than wild type after 48 h inoculation.The expression levels of AtJAR1,AtPDF1.2 and AtNPR1 in overexpressing lines were significantly higher than those in wild type,and the stomatal opening was higher than wild type.The type is small,and the anti-superoxide anion activity is higher than that of the wild type.The ZjJAZ1 transgenic Arabidopsis thaliana responds to the treatment of PstDC3000 pathogen by regulating stomatal opening,reducing ROS content,and increasing the expression level of resistance genes.In addition,this study analyzed a number of important genes involved in plant disease resistance in transcriptome data,including the ZjPYR1-like and ZjSnRK2 genes in the ABA hormone pathway.In this experiment,the two genes were cloned and analyzed,and the PBI121-GFP overexpression vector was constructed and introduced into tobacco by Agrobacterium-mediated genetic transformation.Positive transgenic plants were screened to verify the function of these genes in the next step,which provided an experimental basis for revealing their molecular mechanism of Jujube witche’s broom resistance acquired from Chinese paliurus rootstock.