WUSCHEL emerges as a promising molecular marker of in vitro regeneration competence across diverse poinsettia cultivars

Abstract In vitro regeneration of poinsettia ( Euphorbia pulcherrima ) is strongly genotype-dependent, limiting the efficiency and reproducibility of tissue culture and its biotechnological applications. This study investigated whether regeneration-associated transcription factor expression in stock plants correlates with subsequent regeneration competence across ten poinsettia cultivars. We evaluated EpWUS, EpWIND1 , EpSTM , and EpCYCD expression in stock plants and during direct organogenesis and somatic embryogenesis in relation to regenerated shoot number, shoot regeneration percentage, and developed shoot length. EpWUS showed the most consistent association with regeneration performance across the two regeneration systems. Cultivar-dependent differences in EpWUS expression were already evident in stock plants before regeneration was initiated, and cultivars with relatively high basal EpWUS expression generally exhibited stronger regeneration responses. The association between EpWUS expression and regeneration performance was further supported by correlation analyses across both regeneration systems. In contrast, the expression patterns of EpWIND1 , EpSTM , and EpCYCD showed less consistent relationships with regeneration efficiency. These findings support EpWUS as a candidate molecular marker associated with regeneration competence in poinsettia. However, independent validation and functional studies are required to establish its predictive utility and mechanistic role. The findings provide a basis for developing molecular approaches to improve genotype selection for poinsettia tissue culture and biotechnology.