Isolation of a WRKY30 gene from Muscadinia rotundifolia (Michx) and validation of its function under biotic and abiotic stresses

Abstract

WRKY transcription factors (TFs) play important roles in many plant processes, including responses to biotic and abiotic stresses. In the present study, Muscadinia rotundifolia MrWRKY30 dramatically accumulated in grapevine leaves in response to inoculation of Plasmopara viticola, a pathogen causing grapevine downy mildew disease. Similar responses were also found on grapevines treated with exogenous SA/JA/ET. Ectopic expression of MrWRKY30 in Arabidopsis thaliana "COL0" enhanced its resistance to downy mildew pathogen Peronospora parasitica. Pathogenesis-related (PR) genes, including AtPR1, AtPR4, AtPR5, and AtPDF1.2, were significantly upregulated in transgenic A. thaliana after P. parasitica inoculation. In the mean time, two critical genes in SA and JA signaling pathways, AtEDS5 and AtJAR1, were abundantly expressed as well, indicating that MrWRKY30 may enhance disease resistance of A. thaliana through SA and JA defense system. The transgenic A. thaliana plants also enhanced tolerance to cold stress accompanied with upregulation of AtCBF1, AtCBF3, AtICE1, and AtCOR47. MrWRKY30 might protect A. thaliana from cold damage by activating the AtCBF-mediated signaling pathway to induce the downstream AtCOR47 gene. Interestingly, the transgenic seedlings had a negative effect on salt tolerance. Reverse transcription PCR (RT-PCR) analysis revealed that antioxidant enzyme genes AtAPX (ascorbate peroxidase), AtCAT (catalase), and AtGST (glutathione-S-transferase) were suppressed in transgenic plants, which may lead to reactive oxygen species (ROS)-mediated sensitivity to salt stress.

A Grapevine TTG2-Like WRKY Transcription Factor Is Involved in Regulating Vacuolar Transport and Flavonoid Biosynthesis

“…The final phylogenetic tree was obtained using the neighbor-joining method and bootstrap analysis (1000 replicates) and Mega6 software (Tamura et al, 2013). The following GenBank accession numbers were used: AtWRKY2 (AT5G56270), AtWRKY4 (AT1G13960), AtWRKY6 (AT1G62300), AtWRKY7 (AT4G24240), AtWRKY18 (AT4G31800), AtWRKY23 (AT2G47260), AtWRKY35 (AT2G34830), AtWRKY36 (AT1G69810), AtWRKY42 (AT4G04450), AtWRKY62 (AT5G01900), AtWRKY70 (AT3G56400), AtTTG2 (AT2G37260), VpWRKY1 (ACY69975), VpWRKY2 (ADD70008), VpWRKY3 (AEN71143), VvWRKY01 (AAT46067), VtWRKY11 (B2G283), VvWRKY33 (AHG99400), MrWRKY30 (Jiang et al, 2015), GhWRKY3 (ADI52618.1), PcWRKY1 (AAD55974.1), PcWRKY3 (AAC49528), PcWRKY4 (AAG35658), OsWRKY6 (DAA05071), OsWRKY76 (DAA05141), WIZZ (BAA87058.1), CaWRKY1 (AAO86686), CjWRKY1 (BAF41990). …”

“…In Vitis vinifera the WRKY family is composed of 59 members (Wang M. et al, 2014) and the few proteins functionally characterized so far seem to be mostly involved in plant response to biotic or abiotic stress (Marchive et al, 2007, 2013; Li et al, 2010; Liu et al, 2011; Zhu et al, 2012; Jiang et al, 2015; Merz et al, 2015). In this study, we characterized VvWRKY26, the closest grapevine homolog to PhPH3 and AtTTG2.…”

WRKY Transcription Factors: Molecular Regulation and Stress Responses in Plants

“…Subset of these genes include many transcription factors (TFs) like WRKY, ERF, NAC, and MADS. WRKYs are of particular interest as they are involved in diverse biotic/abiotic stress responses as well as in developmental/physiological processes ( Jiang et al, 2015 ). They recognize the W-box present in the promoter of target genes and induce their expression to achieve cellular homeostsis.…”

Transcription factor SmWRKY1 positively promote the biosynthesis of tanshinones inSalvia miltiorrhiza

“…Subsequently, much attention has been paid to identify and analyze WRKY genes from different model and crop plants, for instance Arabidopsis (Eulgem et al, 2000; Kalde et al, 2003; Wang et al, 2011), soybean ( Glycine max ) (Yin et al, 2013), tobacco (Yoda et al, 2002), rice ( Oryza sativa ) (Wu et al, 2005) and so on. Meanwhile, WRKY has been isolated from some traditional herbal plants including Artemisia annua, Coptis japonica and Catharanthus roseus (Jiang et al, 2015; Chen et al, 2017; Kato et al, 2007; Suttipanta et al, 2011). The significant feature of WRKY transcription factor is their WRKY domain which is approximately 60-amino acid long with the highly conserved amino acid sequence WRKYGQK located at the N-terminal and a non-typical zinc-finger-like motif C2HC (C–X 7 –C–X 23 –H–X 1 –C) or C2H2(C–X 4–5 –C–X 22–23 –H–X 1 –H) at the C-terminus (Xu et al, 2004; Lu et al, 2015).…”