The function of TaWOX14 in wheat genetic transformation.

Key message: Overexpression of TaWOX14 can significantly improve the genetic transformation and genome editing efficiencies of some wheat immature embryos, and TaPLD serves as a promising candidate gene for haploid induction in wheat. Genetic transformation and genome editing systems have the potential for accelerating the breeding process in crops. However, their effectiveness is often limited by the regeneration efficiency of explants. The WUSCHEL-related homeobox (WOX) family, a group of plant-specific transcription factors, plays a crucial role in somatic embryogenesis. In wheat, WOX genes are categorized into three clades: ancient, intermediate, and WUS. In this study, we systematically analyzed the function of the WUS clade genes in wheat transformation. Our results demonstrated that overexpression of TaWOX14 significantly improved genetic transformation efficiencies in several wheat genotypes, including Fielder, Kenong199, Zhengmai7698, and Yangmai13. Furthermore, by combining the CRISPR-Cas9 system with TaWOX14, we observed enhanced genome editing efficiency in the wheat variety Fielder. Additionally, we explored the potential of TaPLD as a candidate gene for haploid induction in wheat. Based on the amino acid sequence of Zea mays PHOSPHOLIPASE D3 (ZmPLD3), we edited its homologs in wheat and identified a TaPLD-edited plant with a ploidy level intermediate between haploid and hexaploid. Overall, these findings are expected to accelerate the wheat breeding process by improving genetic transformation efficiency and identifying a potential haploid induction gene. Future research will focus on further characterizing the mechanisms of TaWOX14 and TaPLD, and exploring their applications in breeding programs.