Abstract: Cotton is one of the most important cash crops in the world, Most of its production areas are in arid or semiaridregions, and drought and salinity seriously affect cotton production, Plant teosinte branched1/cycloidea/proliferating cell factor 1 (TCP) transcription factors play a pivotal role in abiotic stress responses. However, therole of TCPs in the abiotic stress response in cotton has not been fully elucidated, Here, the function of theGbTCP5 transcription factor in the responses to drought and salt stresses was identified. The expression of the GbTCP5 was induced by drought, salt, and abscisic acid (ABA) treatments. The exposure of 35S:GbTCp5 transgenic Arabidopsis to drought stress increased its survival rate and ABA content and decreased its leaf water lossrate and malondialdehyde (MDA) content compared with those of the wild type (WT). In addition, the expressionlevels of the stress response genes AtCOR15, AtCOR414, AtRD29A, AtLTP4, and AtPUB22 and the ABA biosynthesis-related gene AtNCED3 were significantly higher in 35s:GbTCP5 transgenic lines than in the WT. The exposure of 35S:GbTCP5 transgenic Arabidopsis to salt stress accelerated its germination rate, increased its rootlength, survival rate and chlorophyll content, and decreased the MDA content compared with those of the WT. Under drought or salt stress, cotton with virus-induced gene silencing of GbTCP5 showed a decreased survivarate, a shorter root length, a smaller root area, a reduced root volume and a higher MDA content compared with pTRV2 cotton. Transcriptome sequencing results confirmed that GbTCP5 was involved in several abiotic stressrelated metabolic pathways, The results confirmed that GbTCP5 protein activated the expression of GbGLOS2, GbUBC19, and GbERD7 and then participated in the drought and salt tolerance of cotton by binding to the TCPcis-acting element in the promoter regions of these genes. All the above results prove that GbTCP5 plays apositive role in plant responses to drought and salt stress.
