|Delhom, Christopher - Chris|
Submitted to: Journal of Experimental Botany
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 8/3/2016
Publication Date: 8/27/2016
Citation: Hinchliffe, D.J., Condon, B.D., Thyssen, G.N., Naoumkina, M.A., Madison, C.A., Reynolds, M.L., Delhom, C.D., Fang, D.D., Li, P., McCarty Jr, J.C. 2016. The GhTT2_A07 gene is linked to the brown colour and natural flame retardancy phenotypes of Lc1 cotton (Gossypium hirsutum L.) fibres. Journal of Experimental Botany. 67(18):5461-5471. Interpretive Summary: Fibers and textiles produced from naturally colored brown cotton fibers have previously been demonstrated to possess enhanced flame retardancy (FR) compared to white cotton fibers and textiles. In this study we identified the gene responsible for the color and enhanced FR of brown cotton fibers. We also demonstrated the feasibility of separating enhanced FR from brown fiber color. The resulting white cotton fibers could potentially exhibit enhanced FR independent of brown color and be applicable for specific textile applications, reducing or eliminating the need for chemical FR additives.
Technical Abstract: Some naturally-coloured brown cotton fibres from accessions of Gossypium hirsutum can be used to make textiles with enhanced flame retardancy (FR). Several independent brown fibre loci have been identified and mapped to chromosomes, but the underlying genes have yet to be identified, and the mechanism of lint fibre FR is not yet fully understood. In this study, we show that both the brown colour and enhanced FR of the Lc1 lint colour locus are linked to a 1.4 Mb inversion on Chromosome A07 that is immediately upstream of a gene with similarity to Arabidopsis TRANSPARENT TESTA 2 (TT2). As a result of the alternative upstream sequence, the TF GhTT2_A07 is highly up-regulated in developing fibres. In turn, genes in the phenylpropanoid metabolic pathway are activated, leading to biosynthesis of proanthocyanidins and accumulation of inorganic elements. We show that enhanced FR and anthocyanin precursors appear in developing brown fibres well before the brown colour is detectible, demonstrating for the first time that the polymerized proanthocyanidins that comprise the brown colour are not themselves the source of enhanced FR. Identifying the particular, colourless metabolite that provides Lc1 cotton with enhanced FR could help minimize the use of synthetic chemical flame retardant additives in textiles.