AUTHOR=Ayoub Khan Muhammad , Dongru Kang , Yifei Wu , Ying Wang , Penghui Ai , Zicheng Wang 

TITLE=Characterization of WRKY Gene Family in Whole-Genome and Exploration of Flowering Improvement Genes in Chrysanthemum lavandulifolium

JOURNAL=Frontiers in Plant Science

VOLUME=13

YEAR=2022

URL=https://www.frontiersin.org/journals/plant-science/articles/10.3389/fpls.2022.861193

DOI=10.3389/fpls.2022.861193

ISSN=1664-462X

ABSTRACT=<p>Chrysanthemum is a well-known ornamental plant with numerous uses. <italic>WRKY</italic> is a large family of transcription factors known for a variety of functions ranging from stress resistance to plant growth and development. Due to the limited research on the <italic>WRKY</italic> family in chrysanthemums, we examined them for the first time in <italic>Chrysanthemum lavandulifolium</italic>. A total of 138 <italic>ClWRKY</italic> genes were identified, which were classified into three groups. Group III in <italic>C. lavandulifolium</italic> contains 53 members, which is larger than group III of <italic>Arabidopsis</italic>. The number of introns varied from one to nine in the <italic>ClWRKY</italic> gene family. The “WRKYGQK” motif is conserved in 118 members, while other members showed slight variations. AuR and GRE responsive <italic>cis</italic>-acting elements were located in the promoter region of <italic>WRKY</italic> members, which are important for plant development and flowering induction. In addition, the W box was present in most genes; the recognition site for the <italic>WRKY</italic> gene may play a role in autoregulation and cross-regulation. The expression of the most variable 19 genes in terms of different parameters was observed at different stages. Among them, 10 genes were selected due to the presence of CpG islands, while nine genes were selected based on their close association with important <italic>Arabidopsis</italic> genes related to floral traits. <italic>ClWRKY36</italic> and <italic>ClWRKY45</italic> exhibit differential expression at flowering stages in the capitulum, while methylation is detected in three genes, including <italic>ClWRKY31, ClWRKY100</italic>, and <italic>ClWRKY129.</italic> Our results provide a basis for further exploration of <italic>WRKY</italic> members to find their functions in plant growth and development, especially in flowering traits.</p>