Identification Of WD40 Gene Family And Functional Analysis Of ZbTTG1 In Zanthoxylum Bungeanum

WD40 transcription factor plays an important role in plant growth and metabolism,but has not been reported in Zanthoxylum bungeanum(ZB).In this study,the WD40 family members of ZB were identified by bioinformatics method,and their gene structure,evolutionary relationship,expression characteristics and other aspects were systematically and comprehensively analyzed.Finally,the ZbTTG1 gene was focused on and analyzed by gene cloning and Arabidopsis thaliana(AT)genetic transformation.The main conclusions are as follows:(1)A total of 689 WD40 genes were identified in the genome of ZB,which were divided into 16 subfamilies based on gene structure,evolutionary branching and AT grouping.Most of the WD40 genes in prickly ash are hydrophilic and localized in the nucleus.The diverse conserved domains indicated that WD40 gene was relatively less conserved.The WD40 gene in ZB was concentrated and distributed in a certain region of chromosome.There are a large number of sister genes with similar genetic structure in WD40 gene of ZB,and gene expansion events occurred in the process of evolution,in which fragment replication events play a leading role.Cis-element analysis showed that WD40 family was associated with various hormone and abiotic stress responses.Protein interaction network analysis identified 164 WD40 proteins of ZB.,among which 24 WD40 proteins may have complex regulatory relationships.(2)The expression characteristics of WD40 gene in ZB during salt stress and prickle development showed that there were different expression patterns in each subfamily,which suggested that WD40 family of ZB had poor conservation.Based on the transcriptome data of salt stress and prickle development,combined with the functional annotation results of the database,five genes that may be involved in prickle development and four genes related to salt stress were screened out,and the ZbWD40-688(ZbTTG1)gene was identified for subsequent functional analysis.(3)The ZbTTG1 gene was cloned.Bioinformatics analysis showed that ZbTTG1 protein contains 338 amino acids and is located in the nucleus.It is a hydrophilic protein with no signal peptide and no secreted protein.No disulphide bond or transmembrane region was found.Phylogenetic tree analysis showed that ZbTTG1 protein of ZB and TTG1 of sweet orange had relatively close genetic relationship.(4)The ZbTTG1 gene was transferred into wild type and mutant AT.The results showed that overexpression of ZbTTG1 gene inhibited bolting of AT plants,and flowering time was delayed compared with that of wild AT.It was speculated that ZbTTG1 gene could regulate and delay flowering time and plant growth.In addition,the complementary phenotype analysis of AT mutants showed that the mutant plants had a topcoat recovery phenotype,indicating that ZbTTG1 gene could regulate topcoat production.In conclusion,the comprehensive analysis of the WD40 family of ZB was carried out to provide reference for future research on WD40 gene function and exploration of functional genes.The cloning and transformation analysis of ZbTTG1 gene provided a theoretical basis for further using ZbTTG1 gene combined with genetic engineering technology to improve ZB variety and better put into production practice.