Study On The Function Of Fruit Shape Regulatory Genes VvSUN And VvIQD10 In Grape

Fruit quality is divided into appearance quality and internal quality,and shape characteristics are one of the important appearance qualities.The variety of fruit shape is determined by the fruit shape regulation gene.Many members of IQ67 domain(IQ67domain)protein family are reported to be related to the shape of fruit.The regulation of fruit shape is likely to be achieved by changing cell division and cell growth by affecting the movement of cytoskeleton.VvSUN,a member of the IQD gene family in grape,is a direct homologous gene of SUN gene in tomato,and its regulation of fruit shape has been verified.In order to explore the molecular mechanism of VvSUN gene regulating fruit shape,based on previous research progress,this study cloned the promoter fragments of 10 grape varieties with different fruit shapes and the full-length VvSUN gene sequence of 6 representative grape varieties,and analyzed and compared with relevant software.Using the inflorescences of ‘Manicure Finger’,‘Gold Finger’,‘Tianshan’,‘Wink’and ‘Shine Muscate’ as materials,the VvSUN gene expression was analyzed by fluorescence quantitative PCR,and the grapes of‘Manicure Finger’ were selected for organization Specificity analysis.The VvIQD10 gene,a member of the same family with high homology to the VvSUN gene,was cloned from‘Tianshan’ grape.VvIQD10 and VvSUN genes were overexpressed in tobacco,and the mechanism of VvIQD10 and VvSUN proteins was further explored through subcellular localization and protein interaction experiments.The main results are as follows:1.The VvSUN gene promoters of 10 grape varieties with different fruit shapes were not obviously different.There is no significant difference in the full-length sequence of the VvSUN gene of 6 grape varieties with different fruit shapes,except for individual base differences.Fluorescence quantitative PCR analysis showed that the expression level of VvSUN gene was the highest in ‘Tianshan’,and the expression of ‘Manicure Finger’ was the lowest.Tissue-specific analysis showed that VvSUN gene expression was highest in old leaves,and higher in buds one week before flowering and young fruits one week after flowering,which was similar to the expression characteristics of tomato SUN gene.The VvSUN gene promoter and the full length of the sequence may not the main reasons for the changes in fruit shape index.There may be other factors that affect the expression of the VvSUN gene,so that its expression level is different in different varieties when there is no obvious difference between the gene sequence and the promoter sequence.2.The VvSUN gene and VvIQD10 gene were over-expression verified on tobacco.Results showed that the two VvSUN gene transgenic lines have successfully integrated the VvSUN gene,and eight transgenic VvIQD10 genes have successfully integrated VvIQD10 genes,and all of them had been successfully transcribed.The leaf shape index of transgenic VvIQD10 tobacco,trans VvSUN tobacco,and the wild type tobacco during the vegetative growth stage were 2.08,1.69,and 1.68,respectively.Corolla Tube length to flower diameter ratio during the reproductive growth stage of the tobacco was 6.88,5.96,and 5.70,respectively.The fruit shape indexes of mature pods are 2.79,2.45,and 1.87,respectively.Compared with wild-type tobacco,the whole organs of transgenic plants showed a twisted and elongated phenotype,but the degree of elongation and twisting of the organs of transgenic tobacco plants with VvSUN gene was lower than that of transgenic tobacco plants with VvIQD10 gene.3.The open reading frame of the VvIQD10 gene is 1401 bp in length and encodes 466 amino acids;VvIQD10 protein was an unstable hydrophilic protein with no signal peptide and transmembrane domain,but it contained a conserved IQ67 domain.The main structure was alpha helix and random coil.It was closely related to a member of the kiwi IQD family(PSS09955.1).VvIQD10 protein was mainly located in microtubule and plasma membrane,and can directly interacted with the cytoskeleton related protein calmodulin like protein(VvCML);VvSUN protein was mainly located in chloroplast and plasma membrane,and did not interact with VvCML.The recruitment of grape VvCML protein from cytoplasm to microtubule depends on VvIQD10.It is speculated that VvIQD10 protein may regulate the movement of cytoskeleton through binding with calmodulin like proteins,and then participate in the change of grape fruit shape.The VvSUN protein located in chloroplast and plasma membrane may have other ways to regulate fruit shape.