Genome-wide functional analysis of cotton (Gossypium hirsutum) in response to drought.

Cotton is one of the most important crops for its natural textile fibers in the world. However, it often suffered from drought stress during its growth and development, resulting in a drastic reduction in cotton productivity. Therefore, study on molecular mechanism of cotton drought-tolerance is very important for increasing cotton production. To investigate molecular mechanism of cotton drought-resistance, we employed RNA-Seq technology to identify differentially expressed genes in the leaves of two different cultivars (drought-resistant cultivar J-13 and drought-sensitive cultivar Lu-6) of cotton. The results indicated that there are about 13.38% to 18.75% of all the unigenes differentially expressed in drought-resistant sample and drought-sensitive control, and the number of differentially expressed genes was increased along with prolonged drought treatment. DEG (differentially expression gene) analysis showed that the normal biophysical profiles of cotton (cultivar J-13) were affected by drought stress, and some cellular metabolic processes (including photosynthesis) were inhibited in cotton under drought conditions. Furthermore, the experimental data revealed that there were significant differences in expression levels of the genes related to abscisic acid signaling, ethylene signaling and jasmonic acid signaling pathways between drought-resistant cultivar J-13 and drought-sensitive cultivar Lu-6, implying that these signaling pathways may participate in cotton response and tolerance to drought stress