| Summary: | WRKY transcription factors (TFs) containing one or two WRKY domains are a class of plant TFs that respond to diverse abiotic stresses and are associated with developmental processes. However, little has been known about the function of <i>WRKY</i> gene in tea plant. In this study, a subgroup IId <i>WRKY</i> gene <i>CsWRKY7</i> was isolated from <i>Camellia sinensis</i>, which displayed amino acid sequence homology with Arabidopsis <i>AtWRKY7</i> and <i>AtWRKY15</i>. Subcellular localization prediction indicated that CsWRKY7 localized to nucleus. Cis-acting elements detected in the promotor region of <i>CsWRKY7</i> are mainly involved in plant response to environmental stress and growth. Consistently, expression analysis showed that <i>CsWRKY7</i> transcripts responded to NaCl, mannitol, PEG, and diverse hormones treatments. Additionally, <i>CsWRKY7</i> exhibited a higher accumulation both in old leaves and roots compared to bud. Seed germination and root growth assay indicated that overexpressed <i>CsWRKY7</i> in transgenic Arabidopsis was not sensitive to NaCl, mannitol, PEG, and low concentration of ABA treatments. <i>CsWRKY7</i> overexpressing Arabidopsis showed a late-flowering phenotype under normal conditions compared to wild type. Furthermore, gene expression analysis showed that the transcription levels of the flowering time integrator gene <i>FLOWERING LOCUS T</i> (<i>FT</i>) and the floral meristem identity genes <i>APETALA1</i> (<i>AP1</i>) and <i>LEAFY</i> (<i>LFY</i>) were lower in <i>WRKY7</i>-OE than in the WT. Taken together, these findings indicate that CsWRKY7 TF may participate in plant growth. This study provides a potential strategy to breed late-blooming tea cultivar.
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