Comprehensive Sequence Analysis of Gene Family and their Expression Profiling in Grapevine ().

The plant-specific IQ67-domain (IQD) protein family members are downstream targets of calcium sensors, known to regulate plant growth and lateral organ polarity, and basal defense response against environmental cues. No systematic study of gene family has been performed on grapevine. The public availability of grapevine genome enables us to perform identification, phylogeny, chromosomal orientation, and gene structure analysis of the genes in grapevine. We identified 49 genes (-) and further classified them into eight subgroups based on phylogenetic relationships. The 49 genes were assigned to 19 different chromosomal positions. The collinear relationship between grapevine and IQDs ( and ), and within grapevine , was highly conserved. In addition, most of duplicated gene pairs showed / ratio less than 1.00, indicating purifying selection within these gene pairs, implying functional discrepancy after duplication. Transcription profiling of genes shed light on their specific role in grapevine tissue and organ development. The qRT-PCR validation of the 49 genes in grape berry tissue from cultivars with distinct berry shape during developmental phases suggested candidate genes involved in the shape of grape berries. The subcellular prediction of , , , and genes validated their localization in the nucleus and plasma membrane. The VvIQD49 protein interaction with was also verified by bimolecular fluorescence complementation (BiFC) analysis in the plasma membrane. Our findings will be valuable for the functional genomic studies for desirable shape development of grape berries.