Genome-wide identification, expression pattern and subcellular localization analysis of the JAZ gene family in Toona ciliata

The jasmonate ZIM⁃domain (JAZ) is an inhibitor of the jasmonic acid (JA) signal transduction pathway, which plays a vital role in regulating plant growth and development and resisting diseases and insect pests. In this study, bioinformatics methods were used to identify the JAZ gene family from the whole genome of Toona ciliata and the gene characteristics, subcellular location, phylogenetic evolution, promoter cis-elements, and expression patterns were systematically analyzed. A total of 13 TciJAZs gene family members with complete TIFY and Jas domains were identified that were unevenly distributed on 9 chromosomes, encoding 134–400 amino acids, among which the molecular weights (MWs) was 15.75–42.29 kDa. Phylogenetic analysis showed that the TciJAZ gene family could be divided into five subfamilies (Group Ⅰ-Ⅴ) that have close relationships with Citrus clementina, and most TciJAZ family members contain light response and ABA response elements. The transcription factor (TF) families ERF, bZIP, and TCP play many roles with the JAZ family. Subcellular localization results shows that all TciJAZs genes expressed and function in nucleus. RT-qPCR results showed that TciJAZs are mainly expressed in flowers, mature leaves and tender stems. Under MeJA stress, all TciJAZs responded to varying degrees, among which TciJAZ3/4/5/6/7 had a prompt and strong response. Under Hypsipyla robusta stress, TciJAZ1/3/11 expression in leaves and tender stems was significantly upregulated, which may have an anti-insect function. This study provides a basis for further research on TciJAZ genes function and regulatory mechanism in the future and lays the foundation for anti-insect gene selection and insect-resistant breeding of T. ciliata.