Genome-wide and expression pattern analysis of JAZ family involved in stress responses and postharvest processing treatments in Camellia sinensis

Abstract

the JASMONATE-ZIM DOMAIN (JAZ) family genes are key repressors in the jasmonic acid signal transduction pathway. Recently, the JAZ gene family has been systematically characterized in many plants. However, this gene family has not been explored in the tea plant. In this study, 13 CsJAZ genes were identified in the tea plant genome. Phylogenetic analysis showed that the JAZ proteins from tea and other plants clustered into 11 sub-groups. The CsJAZ gene transcriptional regulatory network predictive and expression pattern analyses suggest that these genes play vital roles in abiotic stress responses, phytohormone crosstalk and growth and development of the tea plant. in addition, the CsJAZ gene expression profiles were associated with tea postharvest processing. Our work provides a comprehensive understanding of the CsJAZ family and will help elucidate their contributions to tea quality during tea postharvest processing.Higher plants face a large number of severe challenges during their life cycles, including insect bites, pathogen infection, heavy metal stress, and water scarcity. However, as sessile organisms, plants have evolved sophisticated mechanisms to resist these problems and clever strategies to thrive in their ever-changing natural environments 1,2 . For plants, phytohormones are the most effective and fastest weapon in response to environmental stress. For example, jasmonic acid (JA) is widely known to play an important role in various biological processes in plants, including defense against herbivorous insect attack, flower initiation and plant morphogenesis [3][4][5] .There are at least two jasmonate synthesis pathways that exist in plants, namely octadecane pathway and hexadecanoid pathway, which begins with the release of α-linolenic acid (18:3n-3) and hexadecatrienoic acid (16:3n-3), respectively 6 . The unsaturated fatty acids are catalyzed by a series of enzymes then generates 12-oxo-10,15 (Z)-phytodienoic acid (OPDA), in the chloroplast 7 . Finally, JA is formed through OPDA reductase 3 (OPR3)-mediated reduction reaction and three rounds of β-oxidation 6 . Interestingly, an alternative pathway for JA biosynthesis was discovered. OPDA could enter the β-oxidation pathway to produce a direct precursor of JA and JA-lie in the absence of OPR3 8 . Moreover, the JA signal pathway has been deciphered 9,10 . It has been reported that the JA receptor is a co-receptor complex formed by JAZ protein, COI1 (CORONATINE INSENSITIVE1) protein and inositol pentakisphosphate 11 . Previous studies have revealed that the JA content is maintained at a relatively low level in plants under normal conditions, in which the JAZ repressor interacts with MYC2 to inhibit downstream insect-resistant or disease-resistant gene expression 12 . However, large amounts of JA accumulate in plant cells in response to abiotic or biotic stresses and are perceived by COI1 13,14 . Subsequently, JAZ proteins are degraded by COI1-mediated E3 ubiquitination. Then, the transcription activator MYC is relieved, which increases the expression o...

Genome-Wide Identification of the Tify Gene Family and Their Expression Profiles in Response to Biotic and Abiotic Stresses in Tea Plants (Camellia sinensis)

“…The CsPPD subfamily, which has the same TIFY motif, was also clustered with CsJAZs together in both polygenetic trees, confirming that PPD proteins may be the evolutionary precursors of JAZ and may have evolved as two independent subfamilies by gene duplication in vascular plants [1,6]. A recent study reported that 12 CsJAZ proteins were found through TIFY and Jas domain blast in tea plants [31]. Among the 12 CsJAZ proteins, six members were identical to those in our study, and the other six CsJAZ proteins in the above study both contain the so-called Jas domain, which was only part of the CCT domain but was not a true Jas domain.…”

“…The phylogenetic tree showed that the stronger inducible genes CsJAZ1, CsJAZ2, CsJAZ7, and CsJAZ8 were grouped closer than CsJAZ3 and CsJAZ4, which may suggest that JA-induced CsTIFY genes evolved from common ancestors responsive to JA [7,37]. The identical CsJAZ genes found in a previous study showed that CsJAZ2, CsJAZ3, and CsJAZ4 were remarkably upregulated by MeJA [31]. This difference may be attributable to such factors as different tea varieties, discrepancies in the elicitation effects of JA and MeJA, and differing treatment concentrations.…”

“…The TIFY family is an important plant-specific gene family and has been identified in multiple species among both monocots and eudicots [1,8,10,12]. Continuing research has demonstrated that the members of the TIFY gene family, especially members of the JAZ subfamily, play multiple roles in different plant developmental processes and the process of defense against biotic and abiotic stresses [1,8,10,11,13,31]. As evergreen plants, tea plants are frequently challenged by abiotic and biotic stresses, but information on the TIFY gene family is lacking, which hampers the research investigating resistance mechanisms [27,28,31].…”

“…Continuing research has demonstrated that the members of the TIFY gene family, especially members of the JAZ subfamily, play multiple roles in different plant developmental processes and the process of defense against biotic and abiotic stresses [1,8,10,11,13,31]. As evergreen plants, tea plants are frequently challenged by abiotic and biotic stresses, but information on the TIFY gene family is lacking, which hampers the research investigating resistance mechanisms [27,28,31]. The chromosome-level genomic sequence of the tea plant has been recently released, and the extensive annotated information provided in the tea genome provides fundamental material for comprehensive analysis of the CsTIFY family [32].…”

“…Previous studies based on transcriptomic strategies indicated that JAZ subfamily genes were involved in the interactions between the tea plant and biotic stresses [30]. A recent study also reported that 12 CsJAZ genes were identified in an older version of the tea genome [31]. However, with the recently released chromosome-level genomic sequence of the tea plant [32], information regarding the TIFY family, including the ZML, TIFY, and PPD subfamilies, is still lacking.…”