Overexpression of cotton genes GhHAT5 and GhCRK29 promotes embryonic development in Arabidopsis thaliana

Background Cotton is an industrial crop renowned for its multifaceted applications in the textiles, pharmaceuticals, and biofuel industries. Plant regeneration through somatic embryogenesis (SE) plays a crucial role in the genetic improvement of cotton. There is a strong correlation between SE and zygotic embryogenesis (ZE) in plants. Furthermore, the strategy of ectopic expression of cotton genes into the model plant Arabidopsis has been a widely accepted approach for functional study. Result Based on previous spatial transcriptomics of cotton somatic embryos, two genes, GhHAT5 and GhCRK29 , were identified. They are highly expressed in cotyledon and epidermal cells of cotton cotyledonary embryos, respectively. In this study, GhHAT5 and GhCRK29 were ectopically expressed in Arabidopsis to investigate their functions. The result showed that in Arabidopsis zygotic embryos, the overexpression of GhHAT5 promoted the development of apical embryonic upper-tier cells and embryonic cotyledon, while the overexpression of GhCRK29 promoted the development of apical embryonic lower-tier cells and embryonic radicle. Given the similarities between somatic and zygotic embryogenesis, these findings suggest that GhHAT5 and GhCRK29 are involved in cotton SE. We also speculate that these genes may promote the expression of the Arabidopsis endogenous gene AtSCR , which is crucial for embryonic development. Conclusion These results revealed that GhHAT5 and GhCRK29 regulate embryonic development and are essential in advancing our understanding of cotton SE and facilitating targeted genetic manipulation strategies to improve industrial crop traits and agricultural sustainability.