Bioengineer novel eco-friendly natural colour fibre through genetic manipulation of the phenylpropanoid and betalain pathways in cotton
Cotton fibre is one of our most important textile resources. Most commercial cotton fibres are various shades of white but can be yellowish because of poor environmental conditions during growth or storage. A bleaching step is employed to address this issue during cotton fabric processing. After cotton fibre is spun into yarn, a dyeing process is applied to colour natural fibre to satisfy costumer’s demand. Additional industrial processes are needed to remove unfavourable natural colours and then add desirable colours to the yarn. Each step costs substantial amounts of energy but more importantly causes serious water and air pollution. More than 100 litres of water are required to dye one kilogram of cotton. The industrial effluents are rich in hazardous material. To address these issues, the proposed research will aim to bioengineer high value eco-friendly naturally coloured cotton fibre.  Two overall strategies will be pursued. Firstly, by down-regulating key genes in the phenylpropanoid pathway, we aim to reduce fibre yellowish to increase fibre whiteness for the premium market. Second, by reorientating the metabolic flux from the phenylpropanoid pathway into a heterologously expressed betalain biosynthesis pathway, we aim to engineer novel natural colour cotton. The prospective products will significantly alleviate the environmental issues of the textile industry where 20% of global water pollution is produced and provide a biotechnological solution for a more environmentally friendly textile industry.