Transcriptome-Wide Identification and Characterization of the JAZ Gene Family in Mentha canadensis L.

Dong-Bei Xu,Rui-Cen Liu,Wei Wu,Xia Wang,Wei-Lin Tang,Xi-Wu Qi,Hai-Ling Fang,Teng-Fei Qin,Ze-Qun Chen,Cheng-Yuan Liang,Ya-Nan Ma

doi:10.3390/ijms22168859

Abstract

Jasmonate ZIM-domain (JAZ) proteins are the crucial transcriptional repressors in the jasmonic acid (JA) signaling process, and they play pervasive roles in plant development, defense, and plant specialized metabolism. Although numerous JAZ gene families have been discovered across several plants, our knowledge about the JAZ gene family remains limited in the economically and medicinally important Chinese herb Mentha canadensis L. Here, seven non-redundant JAZ genes named McJAZ1–McJAZ7 were identified from our reported M. canadensis transcriptome data. Structural, amino acid composition, and phylogenetic analysis showed that seven McJAZ proteins contained the typical zinc-finger inflorescence meristem (ZIM) domain and JA-associated (Jas) domain as conserved as those in other plants, and they were clustered into four groups (A-D) and distributed into five subgroups (A1, A2, B1, B2, and D). Quantitative real-time PCR (qRT-PCR) analysis showed that seven McJAZ genes displayed differential expression patterns in M. canadensis tissues, and preferentially expressed in flowers. Furthermore, the McJAZ genes expression was differentially induced after Methyl jasmonate (MeJA) treatment, and their transcripts were variable and up- or down-regulated under abscisic acid (ABA), drought, and salt treatments. Subcellular localization analysis revealed that McJAZ proteins are localized in the nucleus or cytoplasm. Yeast two-hybrid (Y2H) assays demonstrated that McJAZ1-5 interacted with McCOI1a, a homolog of Arabidopsis JA receptor AtCOI1, in a coronatine-dependent manner, and most of McJAZ proteins could also form homo- or heterodimers. This present study provides valuable basis for functional analysis and exploitation of the potential candidate McJAZ genes for developing efficient strategies for genetic improvement of M. canadensis.

Highlights

To identify the putative McJAZ family genes in M. canadensis, in total, twelve wellknown Jasmonate zinc-finger inflorescence meristem (ZIM)-domain (JAZ) protein sequences from A. thaliana [19] and nine reported JAZ protein sequences from A. annua [24] were collected and used as queries to perform a BLASTP search based on the previous transcriptome data (SRP132644) at the National Center for Biotechnology
Based on the available transcriptome data [67], we performed a comprehensive identification of JAZ proteins in M. canadensis and further investigated their sequence characteristics and protein structure, evolutionary relationships, expression profiles, subcellular locations, and protein-protein interactions
This work provided a basis for subsequent functional analysis of JAZ genes to deepen our understanding of jasmonic acid (JA) signaling in the Lamiaceae family, especially in M. canadensis

Summary

Introduction

JA biosynthesis has been deeply explored in dicotyledonous and monocotyledonous plants such as Arabidopsis and rice [5]. These results indicate that JA biosynthesis is initiated by a series of sequential oxygenations of α-linolenic acid using lipoxygenase (LOX), allene oxide synthase (AOS), and allene oxide cyclase (AOC), leading to the synthesis of 12oxo-phytodienoic acid (OPDA). Afterwards, the studies found that (+)-7-iso-Jasmonoyl-L-isoleucine (JA-Ile), synthesized from (+)-7-iso-JA by jasmonate amino acid synthetase 1 (JAR1), is considered the major form of active JA in plants [18,19]

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Conclusion