Effect of Drought Stress on Cotton Fiber Development and Fiber Quality Traits.

Drought is a major environmental stress that reduces cotton yield and fiber quality. Due to the inherent difficulties of studying fiber tissues and the lack of markers to monitor the fiber development, little is known about the regulation of processes (traits) that are critical to the formation of high quality fiber and the association of these traits with drought tolerance in cotton (their performance under drought stress). In this study, we examined the effect of drought stress (3 irrigation levels) on fiber development and fiber quality traits using transgenic cotton lines harboring cellulose synthase A1 (CesA1) gene promoter-GUS gene reporter (CesA1::GUS) construct. GUS activities in fiber tissues of 10-56 dpa bolls were quantitatively determined. The structural and cell wall composition changes in fiber over the sampling time were analyzed using Fourier transform Infrared Spectroscopy (FTIR), Thermogravimetric analysis and SEM. Results revealed that drought stress induced a range of molecular, biochemical and structural changes within cotton fiber cells and the association of these changes with fiber quality traits.