Poster: Vegetative development

Abs # 338: The tissue culture and transformation of Marestail (Conyza canadensis (L.) Cronquist)

Presenter:	Duncan, David R, david.r.duncan@monsanto.com
Authors	Duncan, David R (A)   Tran, Minhtien  (A)   Scheiber, Pamela A (B)
Affiliations:	(A): Monsanto Corporation (B): St. Edwards University

Glyphosate resistant crops can have a huge beneficial impact for the agricultural industry by facilitating the use of the non-selective herbicide RoundUp^® that has very low human and environmental toxicity. The onset of glyphosate resistant weeds, however, has created growing concern about the future utility of these crops. Conyza canadensis (L.) Cronquist (marestail or horseweed) is one such glyphosate resistant weed that has yet to be fully analyzed or established in tissue culture. Tissue culture is used as a valuable tool for examining physiological characteristics of a plant in an aseptic and controlled environment. For the present study, mairstail was culture on a Murashigi and Skoog based medium supplemented with 6-benzylaminopurine, and α-naphthaleneacetic acid. Plant regeneration was accomplished on the same basal medium supplemented with only gibberellic acid. Glyphosate resistance could be demonstrated in cultured tissues. The cultures could also be transformed with Agrobacterium tumefaciens without the need for chemically inducing bacterial virulence with phenolics or glucose and resulting in a transformation rate of about 13%. The optimal growing conditions observed and preliminary data gathered provide the means for further study of the mode of glyphosate resistance expressed by marestail.