Microorganismos endofíticos en plantas in vitro de Dioscorea cayenensis subsp. rotundata Poir clon blanco de Guinea

The present study aimed to characterize microbial contaminants in in vitro plants of Dioscorea cayenensis subsp. rotundata clone white Guinea after multiple subcultures, and to evaluate their control through meristem culture. Uninodal segments were aseptically cultured over seven subcultures. Additionally, meristems were cultured in the presence of naphthaleneacetic acid combined with the cytokinins benzylaminopurine or meta-topoline at different concentrations. A microbial contamination increases exceeding 45 % was observed from the fifth subculture onward. Microbiological analysis using Gram staining, biochemical, and physiological tests allowed for the identification of endophytic bacteria belonging to the genus Pseudomonas in leaf-stem tissues, and Bacillus in roots. Meristem culture in media supplemented with naphthaleneacetic acid (0.1 mg·l-1) and meta-topoline (0.15 mg·l-1) reduced phenolization, promoted sprouting, and enhanced evaluated morphological parameters. These results demonstrate that meristem culture under optimal conditions and hormonal combinations constitutes an effective strategy to control endophytic contaminants and improve the morphogenetic quality of in vitro yam plants, thereby increasing their potential for commercial micropropagation.