Expression of drought tolerance in transgenic cotton

Tolerance against drought in T1 progeny of transgenic cotton (Gossypium hirsutum) previously transformed with GHSP26 (Heat Shock Protein Gene), GUSP1 (Universal Stress Protein Gene), and Phyto-B (Phytochrome-B Gene) was investigated at the vegetative, squaring, and boll formation stage. Detection of transgenes into the progeny plants through PCR showed a Mendelian inheritance pattern (3:1). Real-time PCR quantified the expression of GHSP26 as transgenic plants which tolerated drought stress for 10-12 days at an average of 18 fold more at the vegetative stage which was increased to 19 fold at the squaring stage, while control plants withstood drought period only for 6 days. The gene expression was reduced to 13-fold more (13-15 days) in transgenic lines on an average basis as compared to control plants. Expression of GUSP1 in transgenic progeny at the vegetative and squaring stage was quantified as 22 fold more (11-13 days) and decreased to 15 fold when compared to the control plants which withstood the drought period only for 6 days. Average relative fold expression of Phyto-B transgene as compared to the control was 0.67 more (8 days) at the vegetative stage. Thereafter, expression was elevated to 0.85 fold under drought stress conditions at squaring stage and continued to increase to 3.5 fold higher (14-15 days) at boll formation stage when compared to that of control plants. Most notably, the number of bolls per plant, single boll weight, and seed cotton yield of our transgenic lines were greater than those of non-transgenic plants under drought stress, which is of immense worth.