Genome-Wide Characterization of the Von Willebrand Factor a Gene Family in Wheat: Highlights Their Functional Roles in Growth and Biotic Stress Response

Von Willebrand factor A (vWA) genes play important roles in regulating plant growth and development, as well as biotic stresses. However, limited data are available on the contributions of vWA genes to wheat (<i>Triticum aestivum</i> L.). In this study, 114 <i>TavWA</i> genes were identified in the wheat genome, which were unevenly distributed on 21 chromosomes. According to the phylogenetic analysis, the 114 <i>TavWAs</i> were classified into six groups, two of which (G3 and G6) were unique to wheat. Fifty-five homoeologous gene sets among A, B, and D sub-genomes were detected, which play a crucial role in the expansion of the wheat vWA gene family. Analysis of specific spatiotemporal expression patterns showed that more than 50% of <i>TavWAs</i> (61 out of 114) exhibited tissue-specific expression. These included 71 <i>TavWAs</i> that responded to one or more of the four biotic stress treatments (flg22, chitin, powdery mildew, and stripe rust). Notably, these included <i>TavWA1-7D</i>, a recently reported key growth regulator in wheat, suggesting its additional role in biotic stress responses. RT-qPCR analysis indicated that eight genes (<i>TavWA1-7D</i>, <i>TavWA24-2B</i>, <i>TavWA36-1D</i>, <i>TavWA37-7D</i>, <i>TavWA40</i>, <i>TavWA47</i>, <i>TavWA51</i>, and <i>TavWA53</i>) may play important roles in wheat's powdery mildew resistance. Collectively, the results of this study provide significant insights for future research on the involvement of vWA genes in the development and stress responses of wheat.