Development of highly regenerable callus lines and biolistic transformation of turf-type common bermudagrass [Cynodon dactylon (L.) Pers.]

Common bermudagrass, Cynodon dactylon, is a widely used warm-season turf and forage species in the temperate and tropical regions of the world. Improvement of bermudagrass via biotechnology depends on improved tissue culture responses, especially in plant regeneration, and a successful scheme to introduce useful transgenes. When the concentration of 6-benzylaminopurine was adjusted in the culture medium, yellowish, compact calluses were observed from young inflorescence tissue culture of var. J1224. Nine long-term, highly regenerable callus lines (including a suspension-cultured line) were subsequently established, of which six were used for biolistic transformation. Five independent transgenic events, with four producing green plants, were obtained following hygromycin B selection from one callus line. Three transgenic events displayed resistance to the herbicide glufosinate, and one of these showed -glucuronidase activity since the co-transformation vector used in the experiments contained both the gusA and bar genes.Abbreviations ABA Abscisic acid - BAP 6-Benzylaminopurine - 2,4-D 2,4-Dichlorophenoxyacetic acid - GA ₃ Gibberellic acid - GUS -Glucuronidase - hph Hygromycin phosphate transferase - hyg B Hygromycin B - NAA -Naphthaleneacetic acid - SEC Somatic embryo cluster Communicated by P. Ozias-Akins