Analysis Of Expression Characteristics Of Tomato SNAC4/9 Proteins And Regulation Of Target Genes

NAC transcription factors are unique to plants and have rich biological functions.The SNAC4-9 genes screened in the early stage of the laboratory have been found to be closely related to the growth and development of tomato.In this paper,the physicochemical properties,structure and function of SNAC4-9 proteins were predicted by bioinformatics analysis.The expression of SNAC4/9 proteins in tomato was studied by western blot,and ChIP-seq was used to analyze the downstream target genes,which provided a scientific basis for studying the functions of SNAC4/9.The main findings are as follows:Bioinformatics analysis showed that SNAC4/6 proteins,SNAC5/8 proteins and SNAC7/9 proteins were similar in physicochemical properties,structure,motif and phosphorylation site,respectively,which was consistent with their homology comparison results.It indicated that SNAC4/6 proteins,SNAC5/8 proteins and SNAC7/9 proteins may be involved in similar biological regulation processes,respectively.There were lots of types and numbers of transcription factor binding sites on the promoter of ethylene signal transduction genes,and the binding sites of each promoter had certain similarities,indicating that there may be synergy between each promoter,and the ethylene signal transduction process is complicated.The prokaryotic expression vectors p ET-SNAC4/9 were used to express and purify the SNAC4/9 proteins.The SNAC4/9 proteins were found to be in the form of inclusion bodies.Using the purified proteins,the polyclonal antibody against the SNAC4/9 proteins were obtained.Study on the expression characteristics of SNAC4/9 proteins in tomato showed that the abundance of SNAC4/9 proteins expression was as follows: the expression level in leaves was higher than that in flowers and stems;the expression in radiant wall was significantly higher than that in whole fruit and exocarp;the change in expression was consistent with the fruit ripening process;in tomato fruit,the expression level of SNAC4 was higher than that of SNAC9.The results indicated that SNAC4/9 proteins may be involved in the development and maturation of tomato leaves and radiant wall,and are closely related to the ripening and senescence of tomato fruit.ChIP-seq analysis: There were lots of binding peaks and peak-related genes in the SNAC4/9 samples,and the number of SNAC4 was greater than that of SNAC9,and they were significantly enriched in the 5 kb range from upstream to downstream of TSS.The results of KEGG analysis indicated that the potential target genes of SNAC4 were enriched in pathways such as plant hormone signal transduction and secondary metabolite synthesis.The potential target genes of SNAC9 were enriched in pathways such as aminoacyl t RNA biosynthesis and RNA degradation.There were some differences in the biological functions of SNAC4 and SNAC9 in tomato fruits,and the pathways in SNAC4 were broader.In addition,the pathways enriched by potential target genes of SNAC4/9 also showed some differences in fruits at different maturity stages,indicating that their regulatory mechanisms and biological functions may differ in fruits at different maturity stages.