Analysis Of TCP Transcription Factors Family In Gossypium Barbadense And Functional Verification Of GbTCP5,GbTCP26 And GbTCP47 Genes

TCP transcription factor family is plant-specific and closely related to cell proliferation and growth.It participates in plant growth and development as well as seed germination.It mainly plays a role in meristem and plant growth and development.Existing studies have shown that TCP transcription factors interact with hormone signaling-related proteins,participate in hormone signal regulation during the process of plant growth and development,and participate in plant growth regulation.However,in the Gossypium barbadense,due to the complexity of the genome and the large number of transcription factor families,there are few studies on the TCP gene family of the island cotton,and the number of members and expression characteristics are still unclear.In this study,TCP transcription factors were screened and identified in the genome database of Gossypium barbadense,and their functions were explored.The main results obtained are as follows:1.75 GbTCP genes were identified in Gossypium barbadense,and GbTCP transcription factors were classified into 11 categories according to phylogenetic analysis.Through phylogenetic analysis of Gossypium arboreum,Gossypium raimondii,Gossypium barbadense,Gossypium hirsutum,Arabidopsis,cocoa,Rice and other species,373 TCP genes were divided into Class ? and Class ?.According to qRT-PCR showed that GbTCPs demonstrate different expression patterns in the fibers of different developmental stages of Gossypium barbadense,but with the development of fiber,some TCP genes showed specific expression patterns.2.Using the island cotton 'Xinhai 21'as the research object,the GbTCP5,GbTCP26 and GbTCP47 genes were cloned by PCR.The full length of GbTCP5 gene is 1392 bp,encoding 463 amino acids.The full length of GbTCP26 gene is 1038 bp,encoding 345 amino acids.The full length of GbTCP47 gene is 1056 bp open reading frame encoding 351 amino acids.The yeast transcription activation system showed that the three transcription factors had-no self-activation activity.Subcellular localization shows that these three TCP genes are localized in the nucleus.High expression of GbTCP5 and GbTCP47 genes in 0-5 Day of fiber development was detected by qRT-PCR.The GbTCP26 gene has the highest expression in 15-20 Day of fiber development,and also has high expression in the roots and receptacles.3.When the GbTCP5 gene was overexpressed in Arabidopsis,the number of root hairs in the epidermis and seedlings of the stems and flower buds is significantly increased,and the branches of the plants are also increased.When the gene was overexpressed in upland cotton,the ovule epidermal cells are proliferated and differentiated at the initial stage of fiber development.At this time,qRT-PCR shows a significant increase in the expression of GbTCP5 gene.In mature fibers,the fiber length of the transgenic lines will increase by about 0.8 mm,the clothing fraction will increase by 2.76%,and the plant height will increase by about 10 cm.Therefore,the above results indicated that transcription factor GbTCP5 gene participates in cotton fiber development,affects ovule epidermal cell processes at the initial stage of fiber development,and then affects fiber length and lint percentage at the later stage of fiber development.4.When the GbTCP26 gene was overexpressed in Arabidopsis thaliana it was found that the leaf growth potential of the 10 day old transgenic Arabidopsis thaliana was slightly stronger than that of the wild type,and the number of epidermis on the first pair of cotyledons was significantly higher than that of the wild type.When the gene was overexpressed in Gossypium hirsutum,the length of fiber increased by 0.83-1.87 mm,the uniformity increased by 2.3-3.4%,and the plant height and branch number of transgenic lines increased.Overexpression of this gene in the Gossypium barbadense has a great influence on the overall quality of the fiber,with the length increasing by 1.07 mm-1.63 mm,the uniformity increasing by 2.63%,the breaking specific strength reaching 5.1/cN·tex-1,and the micronaire value increasing 0.1-0.53.These results suggested that GbTCP26 gene may affect fiber quality by participating in physiological activities related to fiber quality development in island cotton.5.Overexpression of Gb TCP47 gene in Arabidopsis thaliana can increase the number of root hair and stem epidermal hair,affect the shape of leaves,increase the density of leaf epidermal hair,and change the distribution of seed coat epidermal hair,increase the number and length of seed coat.Overexpression of GbTCP47 gene in Gossypium barbadense can accelerate the process,elongation and enlargement of ovule epidermal cells at the initial stage of fiber development.Fiber length increased by 0.51-0.93 mm,lint percentage increased by 1.136%-2.913%,and height and branch number of transgenic lines increased.The above results indicated that GbTCP47 transcription factor may be involved in the protrusion of cotton fiber epidermal cells and affected fiber quality.