Cotton seed fibre mutants provide insights into critical determinants of cell wall developmental processes

Pettolino F, Liu S, Moncuquet P, Wilson I, White R, Macmillan C, Yulia D and Llewellyn D

CSIRO Agriculture & Food, Canberra, ACT 2601, Australia.

Plant cell wall composition and structure are important for fundamental processes and agronomic traits. The composition and structure of the developing cotton seed fibre cell wall, and that of mature fibre, are critical determinants of fibre properties including length, fineness, strength and maturity that define commercial fibre quality. For example, fibre cells can reach great lengths due to the controlled flexibility of the walls which allows them to elongate but not widen, and the deposition and organisation of the cellulosic secondary cell wall is essential for strength. We are using multiple approaches to understand and control cell wall composition and its impact on cotton fibre properties. We have undertaken a comprehensive analysis of cell wall composition and gene expression throughout seed fibre development (MacMillan & Birke et al., 2017. BMC Genomics, 18:539); manipulated the expression of cell wall genes involved in fibre composition and quality; and generated fibre quality mutants to identify genes and pathways involved in determining fibre properties. I will present our current findings from the study of a short seed fibre mutant including phenotyping, from the whole plant to the cell wall; transcript profiling; genome sequencing; and gene mapping to identify the mutated gene and understand pathways associated with fibre and cell wall development.