# Genome-Wide Analysis of the JAZ Family in Brassica rapa and the Roles of BrJAZ1a and 6b in Response to Stresses

## TL;DR

This study identifies 25 JAZ genes in Brassica rapa and shows that BrJAZ1a and BrJAZ6b help plants tolerate drought, salt, and disease.

## Contribution

The study reports the functional roles of BrJAZ1a and BrJAZ6b in stress tolerance in Brassica rapa.

## Key findings

- 25 JAZ genes were identified in Brassica rapa based on conserved domains.
- BrJAZ1a and BrJAZ6b enhance drought and salt stress tolerance when overexpressed in Arabidopsis.
- BrJAZ1a and BrJAZ6b are localized in the nucleus and show increased expression under stress conditions.

## Abstract

Jasmonate-ZIM domain (JAZ) proteins act as repressors in the jasmonic acid (JA) signaling pathway and also function as plant-specific proteins participating in plant growth and development, stress response, and defense. In our study, a total of 25 JAZ genes were identified in B. rapa based on their conserved domains. First, the primary characteristics were surveyed, including the lengths of the CDS and proteins, molecular weights, and isoelectric points. Next, a phylogenetic tree of JAZ proteins among B. rapa, A. thaliana, O. sativa, B. oleracea, and B. napus was constructed, which revealed that these proteins cluster into four groups based on sequence homology rather than by species. Synteny analysis of JAZ genes among these species demonstrated that the highest number of collinear pairs was found between B. rapa and B. napus. Most BrJAZ genes were highly expressed in root, stem, and leaf. Moreover, the expression levels of BrJAZ1a and BrJAZ6b were induced by drought, high salt, black rot, and MeJA. Over-expressed these genes in A. thaliana lines enhanced their tolerance to drought and high salt stress, which was associated with higher enzymatic activities of SOD and POD. Both BrJAZ1a-GFP and BrJAZ6b-GFP were localized in the nucleus.