Comprehensive Comparative Analysis of the JAZ Gene Family in Common Wheat (Triticum aestivum) and Its D-Subgenome Donor Aegilops tauschii.

JASMONATE-ZIM DOMAIN (JAZ) repressor proteins work as co-receptors in the jasmonic acid (JA) signalling pathway and are essential for plant development and environmental adaptation. Despite wheat being one of the main staple food crops, until recently, comprehensive analysis of its JAZ gene family has been limited due to the lack of complete and high-quality reference genomes. Here, using the latest reference genome, we identified 17 JAZ genes in the wheat D-genome donor Aegilops tauschii. Then, 54 TaJAZs were identified in common wheat. A systematic examination of the gene structures, conserved protein domains, and phylogenetic relationships of this gene family was performed. Five new JAZ genes were identified as being derived from tandem duplication after wheat divergence from other species. We integrated RNA-seq data and yield QTL information and found that tandemly duplicated TaJAZ genes were prone to association with spike-related traits. Moreover, 12 TaJAZ genes were located within breeding selection sweeps, including 9 tandemly duplicated ones. Haplotype variation analysis of selected JAZ genes showed significant association of TaJAZ7A and TaJAZ13A with thousand-grain weight. Our work provides a clearer picture of wheat JAZ gene evolution and puts forward the possibility of using these genes for wheat yield improvement.

Comprehensive analysis of JAZ family members in Ginkgo biloba reveals the regulatory role of the GbCOI1/GbJAZs/GbMYC2 module in ginkgolide biosynthesis.

Ginkgo biloba L., an ancient relict plant known as a 'living fossil', has a high medicinal and nutritional value in its kernels and leaves. Ginkgolides are unique diterpene lactone compounds in G. biloba, with favorable therapeutic effects on cardiovascular and cerebrovascular diseases. Thus, it is essential to study the biosynthesis and regulatory mechanism of ginkgolide, which will contribute to quality improvement and medication requirements. In this study, the regulatory roles of the JAZ gene family and GbCOI1/GbJAZs/GbMYC2 module in ginkgolide biosynthesis were explored based on genome and methyl jasmonate-induced transcriptome. Firstly, 18 JAZ proteins were identified from G. biloba, and the gene characteristics and expansion patterns along with evolutionary relationships of these GbJAZs were analyzed systematically. Expression patterns analysis indicated that most GbJAZs expressed highly in the fibrous root and were induced significantly by methyl jasmonate. Mechanistically, yeast two-hybrid assays suggested that GbJAZ3/11 interacted with both GbMYC2 and GbCOI1, and several GbJAZ proteins could form homodimers or heterodimers between the GbJAZ family. Moreover, GbMYC2 is directly bound to the G-box element in the promoter of GbLPS, to regulate the biosynthesis of ginkgolide. Collectively, these results systematically characterized the JAZ gene family in G. biloba and demonstrated that the GbCOI1/GbJAZs/GbMYC2 module could regulate ginkgolides biosynthesis, which provides a novel insight for studying the mechanism of JA regulating ginkgolide biosynthesis.

Comprehensive analysis of OsJAZ gene family deciphers rhizobacteria-mediated nutrient stress modulation in rice.

The JASMONATE-ZIM DOMAIN (JAZ) repressors are crucial proteins in jasmonic acid signaling pathway that are critical for plant growth. Therefore, the present study aimed to identify and characterize OsJAZs in the rice genome, revealing their structural attributes, regulatory elements, miRNA interactions, and subcellular localization. 23 JAZ transcripts across the 6 chromosomes of rice genome were identified having conserved domains and different physiochemical characteristics. Phylogenetically classified into five clades, they showed highest syntenic relationship with P. virgatum. The non-synonymous/synonymous values ranged from 0.44 to 1.21 suggesting purifying/stabilizing selection in OsJAZs. The study examined the 1.5 kb promoter region for cis-regulatory elements, and also identified 92 miRNAs targets. Furthermore, homology modeling provided insights into the 3D-structures of JAZ proteins while in-silico gene expression analysis revealed their functional diversity in various tissues and developmental stages. Additionally, qRT-PCR analysis highlighted their involvement in stress adaptation to sub-optimum nutrient conditions induced by plant-beneficial rhizobacteria Bacillus amyloliquefaciens (SN13) in two rice varieties. Distinct OsJAZ expression patterns in the two varieties correlated with altered root architecture, xylem structure, and lignification. These findings affirmed that specific up-or down-regulation of OsJAZs might play critical role in SN13 induced changes in the two varieties that enabled them to survive under stress.

Genome-wide identification and expression analysis of PtJAZ gene family in poplar (Populus trichocarpa).

BACKGROUND: The jasmonate ZIM domain (JAZ) protein is a key repressor of the jasmonate signal transduction pathway, which plays an important role in plant growth and development and defense responses. In this study, based on the published whole-genome data, we identified members of the JAZ gene family in Populus trichocarpa. Through a series of bioinformatic approaches, their expression patterns under various stress conditions have been analyzed to explore and excavate the endogenous resistance genes of poplar and provide a theoretical basis for breeding new varieties of poplar resistance. RESULTS: A total of 13 PtJAZ genes have been identified in P. trichocarpa and designated as PtJAZ1-PtJAZ13. Those 13 PtJAZ genes were unevenly distributed on nine chromosomes, and they could be divided into four subfamilies. The gene structures and motif composition of the members derived from the same subfamily were similar. Collinearity analysis demonstrated that, compared with Arabidopsis thaliana and Oryza sativa, the most collinear pairs (13) were found in P. trichocarpa and Eucalyptus robusta. Cis-acting element analysis suggested that the promoter regions of PtJAZs contained a large number of hormones and stress response elements, of which abscisic acid (ABA) and methyl jasmonate (MeJA) hormone response elements were the most abundant. The PtJAZ genes not only had diverse expression patterns in different tissues, but they also responded to various abiotic and biotic stress conditions. The co-expression network and GO and KEGG analyses showed that JAZ genes were closely related to insect resistance. CONCLUSIONS: In this study, applying bioinformatic methods, 13 PtJAZ gene family members from P. trichocarpa were identified and comprehensively analyzed. By further studying the function of the poplar JAZ gene family, the aim is to select genes with better insect resistance and stress resistance so as to lay a solid foundation for the subsequent breeding of new poplar varieties.