Genome-wide investigation of WRKY transcription factors in Tartary buckwheat () and their potential roles in regulating growth and development.

Background: The WRKY gene family plays important roles in plant biological functions and has been identified in many plant species. With the publication of the Tartary buckwheat genome, the evolutionary characteristics of the WRKY gene family can be systematically explored and the functions of () genes in the growth and development of this plant also can be predicted.

Methods: In this study, the genes were identified by the BLASTP method, and HMMER, SMART, Pfam and InterPro were used to determine whether the genes contained conserved domains. The phylogenetic trees including and genes in other plants were constructed by the neighbor-joining (NJ) and maximum likelihood (ML) methods. The intron and exon structures of the genes were analyzed by the gene structure display server, and the motif compositions were analyzed by MEME. Chromosome location information of genes was obtained with gff files and sequencing files, and visualized by Circos, and the collinear relationship was analyzed by Dual synteny plotter software. The expression levels of 26 genes from different groups in roots, leaves, flowers, stems and fruits at the green fruit, discoloration and initial maturity stage were measured through quantitative real-time polymerase chain reaction (qRT-PCR) analysis.

Results: A total of 76 genes identified from the Tartary buckwheat genome were divided into three groups. genes in the same group had similar gene structures and motif compositions. Despite the lack of tandem-duplicated gene pairs, there were 23 pairs of segmental-duplicated gene pairs. The synteny gene pairs of genes and genes were the most. was highly expressed in roots and may perform similar functions as its homologous gene , playing a role in lateral root and hairy root formation. , and were highly expressed in fruits and may play an important role in fruit development.

Conclusion: We have identified several candidate genes that may perform critical functions in the development of Tartary buckwheat root and fruit, which need be verified through further research. Our study provides useful information on genes in regulating growth and development and establishes a foundation for screening genes to improve Tartary buckwheat quality.