关键词: 枣, 枣疯病, 转录组, 内源激素, 保护酶, 发病机理

Abstract:

This research used healthy and infected Ziziphus jujuba Mill.‘Muzao’to investigate the
pathogenicity and mechanism of Jujube witches’ broom disease. Five endogenous hormones（IAA，Zeatin，
SA，ABA，and GA3）content and three antioxidant enzymes（POD，SOD，CAT）activities were determined
at 10–60 days after flower bud stage. The differentially expressed genes（DGEs）were screened by
transcriptome sequencing. Genes associated with hormones and protective enzymes metabolic pathways
were identified using qRT-PCR. The results showed that the Zeatin and SA contents of infected plants
began to increase significantly at 30 d and 50 d，respectively，after flower bud stage；the CAT activity
tended to decrease first，and increased significantly at 60 d after flower bud stage. Based on transcriptome
analysis，1 669 DGEs were identified unique in the diseased plants，among which 1 114 DGEs were up-regulated genes and 555 were down-regulated ones. GO analysis indicated significant enrichment in
biological process，metabolic process and catalytic activity；and KEGG pathway analysis showed
significant enrichment in biosythesis of secondary metabolites. Among the differentially expressed genes，
15 key genes were screened to be related to the metabolism of hormones and protective enzymes. The
results indicated that the expression of ZjNCED，ZjGA20，ZjPAL，ZjPOD2 and ZjPOD5 was consistent
with the change of the hormone content and the protective enzyme activity shown by qRT-PCR，which
suggested that they may play important roles in the dynamic changes of endogenous hormones content and
protective enzyme activity in infected plants. The changes in gene expression and disorder of hormones
and protective enzymes caused by phytoplasma infection may be the cause of deformity in jujube.

Key words: Chinese jujube；Ziziphus jujuba；Jujube witches&rsquo, broom disease；transcriptomic analysis；plant hormone；protective enzyme；pathogenesis