AUTHOR=Lei Lei , Dong Kun , Liu Siwen , Li Yadong , Xu Guohui , Sun Haiyue 

TITLE=Genome-wide identification of the WRKY gene family in blueberry (Vaccinium spp.) and expression analysis under abiotic stress

JOURNAL=Frontiers in Plant Science

VOLUME=15

YEAR=2024

URL=https://www.frontiersin.org/journals/plant-science/articles/10.3389/fpls.2024.1447749

DOI=10.3389/fpls.2024.1447749

ISSN=1664-462X

ABSTRACT=<sec><title>Introduction</title><p>The <italic>WRKY</italic> transcription factor (<italic>TF</italic>) family is one of the largest <italic>TF</italic> families in plants and is widely involved in responses to both biotic and abiotic stresses.</p></sec><sec><title>Methods</title><p>To clarify the function of the <italic>WRKY</italic> family in blueberries, this study identified the <italic>WRKY</italic> genes within the blueberry genome and systematically analyzed gene characteristics, phylogenetic evolution, promoter <italic>cis</italic>-elements, expression patterns, and subcellular localization of the encoded products.</p></sec><sec><title>Results</title><p>In this study, 57 <italic>VcWRKY</italic> genes were identified, and all encoding products had a complete <italic>WRKY</italic> heptapeptide structure and zinc-finger motif. The <italic>VcWRKY</italic> genes were divided into three subgroups (I-III) by phylogenetic analysis. Group II was divided into five subgroups: IIa, IIb, IIc, IId, and IIe. 57 <italic>VcWRKY</italic> genes were distributed unevenly across 32 chromosomes. The amino acids ranged from 172 to 841, and molecular weights varied from 19.75 to 92.28 kD. Intra-group syntenic analysis identified 12 pairs of duplicate segments. Furthermore, 34 <italic>cis</italic>-element recognition sites were identified in the promoter regions of <italic>VcWRKY</italic> genes, primarily comprising phytohormone-responsive and light-responsive elements. Comparative syntenic maps were generated to investigate the evolutionary relationships of <italic>VcWRKY</italic> genes, revealing the closest homology to dicotyledonous <italic>WRKY</italic> gene families. <italic>VcWRKY</italic> genes were predominantly expressed in the fruit flesh and roots of blueberries. Gene expression analysis showed that the responses of <italic>VcWRKY</italic> genes to stress treatments were more strongly in leaves than in roots. Notably, <italic>VcWRKY13</italic> and <italic>VcWRKY25</italic> exhibited significant upregulation under salt stress, alkali stress, and saline-alkali stress, and <italic>VcWRKY1</italic> and <italic>VcWRKY13</italic> showed notable induction under drought stress. Subcellular localization analysis confirmed that <italic>VcWRKY13</italic> and <italic>VcWRKY25</italic> function within the nucleus.</p></sec><sec><title>Conclusion</title><p>These findings establish a foundation for further investigation into the functions and regulatory mechanisms of <italic>VcWRKY</italic> genes and provide guidance for selecting stress-tolerant genes in the development of blueberry cultivars.</p></sec>