Genome-Wide Identification and Characterization of WOX Genes in Amorphophallus konjac and Functional Analysis of AbWOX2 in Amorphophallus bulbifer During Somatic Embryogenesis

Background: Konjac (Amorphophallus spp.) is an economically important crop valued for the glucomannan content in its corms. Currently, the konjac industry faces germplasm degeneration due to long-term asexual propagation. Developing tissue culture and genetic transformation techniques is essential for its genetic improvement. The WUSCHEL-related homeobox (WOX) transcription factors are critical regulators of somatic embryogenesis and stem cell maintenance in plants. Methods: In this study, we performed genome-wide identification and characterization of WOX genes in the A. konjac reference genome. Furthermore, comparative transcriptomic analyses and functional verification were conducted in A. bulbifer. Results: A total of 12 AkWOX genes were identified in A. konjac, and their structural features were documented. Comparative transcriptomic analysis of A. bulbifer revealed that AbWOX genes were differentially expressed between embryogenic calli (EC) and non-embryogenic calli (nEC). Notably, AbWOX2 was significantly upregulated in EC. Overexpression of AbWOX2 significantly promoted callus proliferation and shoot regeneration in A. bulbifer. Furthermore, AbWOX2-overexpressing lines exhibited a 5.3-fold increase in genetic transformation efficiency (from 5.12% to 27.31%) compared to the control. Conclusions: We characterized the diverse expression patterns of the WOX gene family in Amorphophallus. Crucially, we identified specific individual members—most notably the markedly upregulated AbWOX2—that function as pivotal drivers of somatic embryogenesis and serve as promising candidates for enhancing regeneration and genetic engineering efficiency in Amorphophallus species.