• GN-WOX6 plays distinct roles in morphogenesis, regeneration, and metabolism. • GN-WOX6 induces somatic embryogenesis followed by cell suspension lines in tobacco. • Synergy of GN-WOX6 and GN-WUS2 interaction lessens developmental defects in tobacco. • Candidate proteins from the proteomic study explain the observed phenotypes. • GN-WOX6 overexpression induces somatic embryogenesis in banana. Plant growth regulators can overcome regeneration recalcitrance in plants, yet the molecular mechanisms mediated by developmental regulators (DRs) remain poorly understood. We identified and cloned three DRs, WOX6, WUS2 , and BBM2 from the banana cultivar Grand Naine. GN-WOX6 was expressed alone or in combination with GN-WUS2 and GN-BBM2 in tobacco and banana, and evaluated on hormone-free MS medium. In tobacco, expression of GN-WOX6 induced diverse callus types and embryogenic cell suspensions but failed to regenerate normal plantlets. Co-transformation of GN-WOX6 tissues with GN-WUS2 restored morphogenetic competence and enabled plantlet regeneration. Expression analysis of co-transformed tissues revealed activation of the LAFL network with strong upregulation of LEC2.2, PIN1, COP1 , and YUCCA6 , linking DR activity to hormone biosynthesis. Biochemical and proteomic analyses indicated increased zeatin and ABA accumulation, upregulation of isoprenoid and phytosterol biosynthesis genes, and enrichment of transcription factors, chromatin remodelers, and hormone transporters in embryogenic tissues. These findings establish GN-WOX6 as a dual-function regulator with synergistic roles alongside GN-WUS2 and GN-BBM2 , offering a powerful framework for improving hormone-independent regeneration, metabolic reprogramming, and valuable traits development in banana and other recalcitrant crops.
Chaudhary et al. (Wed,) studied this question.