| Histone acetylation modification is a kind of important epigenetic process in which histone acetyltransferase(HAT)and histone deacetylase(HDAC)function to dynamically regulate the balance of histone acetylation in the nucleus and thus regulate gene expression.GCN5(GENERAL CONTROL Non-Repressible 5)is a very important member of the histone acetyltransferase fami1 y,which has been proven to play important roles in plant growth and development.Mutations in GCN5 in plants lead to diverse growth defects,including abnormal meristem,loss of apical dominance,dwarfism,shorter petals,shorter male flowers,and so on.GCN5 is also involved in regulation of various biological processes,such as cell differentiation,juvenile-to-adult phase transition,iron homeostasis,fatty acid biosynthesis,cuticular wax accumulation,de novo shoot regeneration,gynoecium development.Moreover,GCN5 gene also plays important roles in plants resistance to abiotic stress,such as participating in heat stress resistance,regulating iron homeostasis in plants,and resisting light stress,cold stress and phosphate deficiency,etc.In this study,the histone acetyltransferase(HAT)gene family members were identified,screened and analyzed using the genomic data of Gossypium hirsutum,and the role of GhGCN5＿A11 in the development of cotton fiber was preliminarily verified.This study provides useful clues to enhance the quality of cotton fiber.The main results are as follows:1.To understand the HAT family phylogenetic relationship more clearly,genome-wide identification of the HAT genes from several genome databases was performed.Among them,7 genes,12 genes,11 genes,25 genes,25 genes and 12 genes were identified in Oryza sativa,cocoa,G.arboretu,G.hirsutum,G.barbadense,and Arabidopsis,respectively.Then,the evolutionary tree was built,and the results showed that the HAT genes were conserved in evolution and were divided into four classes.The analysis of the gene structure and protein domains of the 25 HAT family genes in G.hirsutum showed that the HAT genes in the different subfamilies were very conservative.Analysis of the expression patterns in various tissues of cotton showed that GhGCN5＿A11 was highly expressed at the initial stage of fiber development.2.The transient expression of 35S:GhGCN5-GFP in tobacco indicated that GhGCN5＿A11 was localized in the nucleus.GhGCN5＿A11 protein was also inducible expressed in E.coli and purified before verification by Western blot.With protein interaction prediction,we found that histone H3.3–Gh HH3-22(Gh05G2150)was a potential interaction factor.An experiment with Bimolecular Fluorescent complementary(Bi FC)was conducted to confirm the direct interaction between the GhGCN5＿A11 and Gh HH3-22.The results showed that there was an interaction between the GhGCN5＿A11 and Gh HH3-22 in yeast and in planta,and GhGCN5＿A11 could play its role by acting on histone Gh HH3-22.3.Compared with wild-type,the trichome number of gcn5-5 mutant decreased and the trichome number of the Arabidopsis with overexpression of GhGCN5＿A11increased.In G.hirsutum,after silencing endogenous GhGCN5＿A11 gene by VIGS technique,it was found that the fiber length of the silenced lines was shorter and the fiber initiation was retarded.The results showed that GhGCN5＿A11 could promote the development of trichome in Arabidopsis thaliana and play an important role in the initiation and elongation of cotton fiber4.Real time fluorescent quantitative method(QRT–PCR)was used to screen and detect the downstream genes of GhGCN5＿A11 in regulation of trichome development.It was found that GhGCN5＿A11 may regulate the development of cotton fiber by directly regulating the expression of GL1,Gl2,GL3 or some genes in GA pathways. |
