Twenty-Five Years after Beasley and Ting: Revealing Fundamental Properties of Fiber-Growth with Cotton Ovule Cultures
Apr 19, 2019
Since the initial description of culture conditions for growing fiber in vitro by Beasley and Ting in 1973 many laboratories, including the Cotton Fiber Bioscience Research Unit, have used cotton ovule cultures to answer questions about fiber development. Fiber growth on developmental mutants cultured in vitro was similar to patterns seen in planta, however subtle differences in the production of cell wall polymers were detected by gel permeation chromatography of cultured fibers compared with in planta fibers. Fiber cells from cotton ovule cultures proved to be exceptional starting material for isolating cytoskeletons from plant cells for biochemical characterization. Adding alpha-amanitin to ovule cultures inhibited the normal progression of fiber development depending on when the transcription inhibitor was added. The inhibition was reversible during the early stages of fiber initiation and cell elongation, but irreversible if ovules were left in contact with alpha-amanitin for greater than five days. This observation suggests that there is a window of opportunity for fiber cell initials to develop into elongated fiber cells. If fiber cells do not differentiate within 4-6 days post-anthesis, fibers lose their capacity to differentiate. Current research is directed toward showing that the same mechanisms leading to the loss in capacity to differentiate operate to regulate gene expression during fiber development. Our laboratory is also developing conditions that will be suitable for growing cotton ovule cultures aboard the International Space Station to monitor the effects of microgravity on fiber gene expression and cell wall structure.