Abstract
Background Low temperature is a common biological abiotic stress in major cotton growing areas. Cold stress significantly affects the growth, yield and yield quality of cotton. Therefore, it is important to develop a more robust and cold stress tolerant cotton germplasms. In response to climate change and erratic conditions, plants have evolved various survival mechanisms, one of which induction of various stress responsive transcription factors, such as the C-repeat binding factors (CBFs), which have been found to enhance cold tolerance in various plants. Results In this study detailed evaluation of the cotton CBF has been carried out. A total of 29, 28, 25, 21, 30, 26 and 15 proteins encoded by the CBF genes were identified in Gossypium herbaceum, Gossypium arboreum, Gossypium thurberi, Gossypium raimondii, Gossypium turneri, Gossypium longicalyx and Gossypium australe, respectively. Phylogenetic evaluation revealed that the proteins were grouped into seven clades, with clade 1 and 6 being the largest. Moreover, majority of the proteins encoded by the genes were predicted to be located within the nucleus, while some were distributed in other parts of the cell. Based on the transcriptome and RT-qPCR analysis, Gthu17439 (GthCBF4) was highly upregulated under cold stress, and was further validated through forward genetics. The Gthu17439 (GthCBF4) overexpressed plants showed a significantly tolerance to cold stress, with higher germination rate, higher root growth and high induction levels of stress responsive genes. The over-expressed plants exhibited low level of oxidative damage, due to significant reduction in the H2O2 production. Conclusion The results showed that the Gthu17439 (GthCBF4) could be playing a significant role in enhancing cold stress tolerance in cotton and can be further exploited in developing cotton germplasm with an improved cold-stress tolerance