Biolistic Transformation of Cotton Zygotic Embryo Meristem.

Biolistic transformation of cotton (Gossypium hirsutum L.) meristems, isolated from mature seed, is detailed in this report. A commercially available, helium-driven biolistic device (Bio-Rad PDS1000/He ) was used to bombard gold particles coated with a marker gene (uidA or "GUS") into the shoot meristem. The penetration of gold particles was dependent on bombardment parameters, and it was mostly one- to two-cell layers deep. Stable transformation of epidermal L1 layer was consistently observed in approximately 5% of the seedlings. Germ line transformation was observed in up to 0.71% of bombarded meristems by several laboratories. Using this method identification of germ line transformation is laborious and time-consuming. However, the protocol described here represents a simple and efficient method for generating germ line transformation events. In addition, this procedure offers a quick method to evaluate gene constructs in cotton tissues (embryos, cotyledons, leaf) especially fibers which originate as single cells from the maternal epidermis layer.