AUTHOR=Su Wenjuan , Zhou Zengliang , Zeng Jin , Cao Ruilan , Zhang Yunyu , Hu Dongnan , Liu Juan 

TITLE=Genome-wide identification of the WRKY gene family in Camellia oleifera and expression analysis under phosphorus deficiency

JOURNAL=Frontiers in Plant Science

VOLUME=14

YEAR=2023

URL=https://www.frontiersin.org/journals/plant-science/articles/10.3389/fpls.2023.1082496

DOI=10.3389/fpls.2023.1082496

ISSN=1664-462X

ABSTRACT=<p><italic>Camellia oleifera</italic> Abel. is an economically important woody edible-oil species that is mainly cultivated in hilly areas of South China. The phosphorus (P) deficiency in the acidic soils poses severe challenges for the growth and productivity of <italic>C. oleifera</italic>. WRKY transcription factors (TFs) have been proven to play important roles in biological processes and plant responses to various biotic/abiotic stresses, including P deficiency tolerance. In this study, 89 WRKY proteins with conserved domain were identified from the <italic>C. oleifera</italic> diploid genome and divided into three groups, with group II further classified into five subgroups based on the phylogenetic relationships. WRKY variants and mutations were detected in the gene structure and conserved motifs of <italic>CoWRKYs</italic>. Segmental duplication events were considered as the primary driver in the expanding process of WRKY gene family in <italic>C. oleifera</italic>. Based on transcriptomic analysis of two <italic>C. oleifera</italic> varieties characterized with different P deficiency tolerances, 32 <italic>CoWRKY</italic> genes exhibited divergent expression patterns in response to P deficiency stress. qRT-PCR analysis demonstrated that <italic>CoWRKY11</italic>, -<italic>14</italic>, <italic>-20</italic>, -<italic>29</italic> and -<italic>56</italic> had higher positive impact on P-efficient CL40 variety compared with P-inefficient CL3 variety. Similar expression trends of these <italic>CoWRKY</italic> genes were further observed under P deficiency with longer treatment period of 120d. The result indicated the expression sensitivity of <italic>CoWRKYs</italic> on the P-efficient variety and the <italic>C. oleifera</italic> cultivar specificity on the P deficiency tolerance. Tissue expression difference showed <italic>CoWRKYs</italic> may play a crucial role in the transportation and recycling P in leaves by affecting diverse metabolic pathways. The available evidences in the study conclusively shed light on the evolution of the <italic>CoWRKY</italic> genes in <italic>C. oleifera</italic> genome and provided a valuable resource for further investigation of functional characterization of <italic>WRKY</italic> genes involved to enhance the P deficiency tolerance in <italic>C. oleifera.</italic></p>