Cotton ovule culture: A tool for basic biology, biotechnology and cotton improvement

Nearly 30 years ago the conditions for culturing immature cotton ovules wer e established to serve as a working research tool for investigating the phy siology and biochemistry of fibre development. Not only has this tissue cul ture method been employed to characterize the biochemistry of plant cell ex pansion and secondary cell wall synthesis, but ovule cultures have contribu ted to numerous other aspects of plant cell physiology and development as w ell. In addition to basic studies on fiber development, cotton ovule cultur es have been used to examine plant-fungal interactions, to model low temper ature stress responses, to elucidate the pathways responsible for pigment f ormation in naturally pigmented fiber and to probe how cytoskeletal element s regulate cell wall organization. Success in rescuing Gossypium interspeci fic hybrids was dependent on ovule culture media formulations that could su pport early embryo development in ovulo. As tissues produced in culture are analyzed by increasingly more sophisticated techniques there appear to be some differences between ovule growth in planta and ovule growth in vitro. Discerning how ovule culture fiber development is different from fiber deve lopment in field-grown plants can contribute valuable information for crop improvement. Cotton ovule cultures are an especially attractive model syste m for studying the effects of gravity on cell elongation, cellulose biosynt hesis and embryo development and are excellent target for examining transie nt expression of introduced gene constructs. With only minor modification, the procedure originally described by C. A. Beasley; and I. P. Ting for gro wing cotton ovules in vitro will continue to le a useful research tool for the foreseeable future.