Polysaccharide composition during cotton seed fibre development: temporal differences between species and in different seasons

Background: Cotton seed fibres are long single-celled epidermal trichomes that first appear on the surface of the ovule at anthesis and then elongate rapidly over a period of 15–25 days until a secondary cell wall (SCW) begins to develop through a rapid increase in the deposition of microfibrillar cellulose between the plasma membrane and the primary cell wall that eventually terminates elongation. Quantitative measurements of the different polysaccharide components in both wall types over time and how they influence fibre quality can direct studies involved in enhancing fibre properties for yarn quality through cell wall manipulation or molecular breeding. Results: A detailed chemical analysis of cell wall composition by differential solvent fractionation was used to identify the range of polysaccharides present in mature cotton fibres and used to validate a simpler total cell wall monosaccharide linkage analysis protocol for wall compositional analysis. Analysis of fibres from 5 days post-anthesis through maturity for three cultivated species, Gossypium hirsutum, G. barbadense, and G. arboreum, showed the dynamic nature of cell wall polysaccharide composition through fibre development and that it progressed differently for each species. Plants grown in the glasshouse during either autumn to winter or spring to summer and within each species had fibre qualities and temporal aspects of cell wall development that were different for each season. Notably, the timing of the deposition of the SCW was delayed in winter grown plants and appeared to influence key fibre quality properties. Conclusions: These results suggest that the temporal aspects of cell wall polysaccharide biogenesis during fibre development influence final fibre quality, and this timing is determined by both genetic and environmental factors. The onset of SCW synthesis appears to be a critical factor coinciding with termination of fibre elongation and specifying the duration of wall thickening that then affects fibre length and other wall-associated quality parameters that ultimately determine yarn quality.