Enhanced Expression of Plasma Membrane Intrinsic Protein 2 Improves Cotton Fiber Length and Potential Economic Viability of Gossypium Arboreum

Background: Gossypium arboreum is a cotton crop native to tropical and subtropical regions that are naturally resistant to Cotton Leaf Curl Virus (CLCuV). However, its cultivation is unfavorable due to the lower quality and shorter fiber length of cotton when compared to the market leading Gossypium hirsutum. Plasma membrane intrinsic protein 2 (PIP2) is an aquaporin responsible for the transport of water and small molecules across cellular membranes. This fluid transport influences cell elongation and cotton fibre development. Hence, increased PIP2 expression may yield plants with enhanced fiber qualities including length. Methods and Results: To test this hypothesis, G. arboretum was transformed with a PIP2 gene construct (35SCpPIP2)using the Agrobacterium-mediated shoot apex cutting method. Relative expression of the CpPIP2 gene in transgenic plants increased up to 35-fold when compared with non-transgenic controls. Transgenic plants displayed a corresponding increase of staple length (up to 150%) when compared with non-transgenic controls. Transgene integration was examined using FISH and karyotyping and revealed the presence of a single transgene located on chromosome 6. Conclusion: Since G. arboreum is naturally whitefly and CLCuV resistant, this improvement of fiber length evidenced for CpPIP2 transgenic plants renders their crop production more economically viable.