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[Objectives]The paper aimed to identify the grape homeobox(HB)gene family using bioinformatics methods, systematically analyze their sequence and structural characteristics, evolutionary features and expression characteristics, and screen candidate grape HB genes in response to bud dormancy and various stresses. [Methods]Using the local BLAST program, the HB gene in Arabidopsis thaliana was used as the target sequence for comparison with the grape whole genome protein sequence. ExPASy was used to predict the physical and chemical properties of grape HB gene family proteins, and MapGene2Chro was used to locate chromosomes. Based on Neighbour-joining method, the MEGA X software was used to perform phylogenetic tree of these HB genes in grape and A.thaliana. Meanwhile, TBtools software was used to analyze the gene structure, conserved domain and promoter cis-elements characteristics of HB family members. Genomic collinearity of HB gene family members between grape and A.thaliana was analyzed by MCScanX. Based on known transcriptomic data, the expression of HB genes was analyzed under bud dormancy, fruit development and different abiotic stresses. [Results]Eighty HB genes were identified in the grape genome, distributed on 18 chromosomes, which were divided into 9 subfamilies based on evolutionary analysis. The amino acid quantity was 66-1 772, molecular weight was(8.28-198.55)×103 and isoelectric point was 4.60-10.03. The prediction of subcellular localization indicated that the family members were mainly located in chloroplasts. Gene structure analysis revealed that all grape HB members contain exons ranging from 1 to 20 in number. There were 2 pairs of tandem duplicated genes and 23 co-linear pairs in the grape HB gene family, and 82 co-linear pairs between A.thaliana and grape. Promoter cis-elements analysis showed that the HB family contained cis-elements related to light response, plant hormones and stress, and tissue-specific expression. Among grape HB family proteins, KNOX and BEL subfamily members had the closest interaction. Through the analysis of the expression profile of grape HB gene family, it was found that most HB family members were significantly differentially expressed under bud dormancy and drought stress. In addition, seven HB family members were found to be involved in bud dormancy regulation, and VvHB9 and VvHB34 were involved in various abiotic stresses. [Conclusions]In this study, basic information was identified and analyzed on the members of the grape HB family, and several key genes were screened which were involved in the regulation of bud dormancy and response to multiple abiotic stresses based on transcriptomic data. [ABSTRACT FROM AUTHOR]

[Objectives] The objectives of this study were to identify the defensin-like(DEFL) gene family of pear(Pyrus bretschneideri) genome, and analyze their sequence characteristics, evolutionary relationship, gene structure, conservatively functional domains of amino acid sequences, chromosomal locations and expression characteristics, and provide a reference to the functional research and application of PbrDEFL.[Methods] Based on the whole genome sequencing of P. bretschneideri, the sequences of PbrDEFL were identified and analyzed by bioinformatics. Quantitative real-time PCR(RT-qPCR) and transcriptome data were used to analyze the expression patterns of PbrDEFL from various tissues and different stages of pollen tube development. Subcellular localization was used to analyze the distributions of PbrDEFL38 and PbrDEFL15 in cells. Optimum conditions were established for the production and purification of recombinant PbrDEFL38 and PbrDEFL15 from Escherichia coli.[Results] The results showed that PbrDEFL family were divided into 2 groups, which included 39 DEFL genes(PbrDEFL1-PbrDEFL39) containing the stable cysteine αβ model(CS αβ motif). Members of PbrDEFL gene family were unevenly distributed among 9 chromosomes and purification selection was the driving force of PbrDEFL gene family. RT-qPCR analysis showed that the expression of PbrDEFL presented tissue-specificity, mainly expressed in pollen or leaves; and over 60% of PbrDEFL genes showed a single peak expression trend during the pollen tube development in two pear cultivars('Dangshansuli' and 'Huanghua'). The prediction of PbrDEFL subcellular localization indicated that all proteins were located outside the cell, which was further confirmed by transient expression of PbrDEFL38-GFP and PbrDEFL15-GFP in tobacco. Additionally, the expression and purification conditions of PbrDEFL38 and PbrDEFL15 from E.coli were further analyzed. And the most suitable induction was 15℃ and 0.5 mmol·L-1 IPTG.[Conclusions] This study showed that the members of PbrDEFL gene family were highly conserved, and function was mainly outside the cell. It played an important role in the process of plant immune defense as well as in the pear pollen tube growth and self-incompatibility. [ABSTRACT FROM AUTHOR]