title: Cloning and characterization of VIGG, a novel virus-induced grapevine protein, correlated with fruit quality.
abstract: We report here the identification and characterization of VIGG, a novel virus-induced grapevine protein. Analysis of VIGG expression in grapevine demonstrated that VIGG was constitutively expressed in leaves and stems in virus-infected grapevine, and that VIGG expression was induced by grapevine virus A (GVA) infection, but not by infection with other viruses. The virus-induced expression profile of VIGG was supported by the finding that virus-free meristem cultures prepared from virus-infected grapevines did not express VIGG. An experiment using GFP-VIGG fusion protein demonstrated that VIGG might be localized in or around the endoplasmic reticulum (ER). Treatment of grapevine cells with ER stress inducers resulted in the induction of VIGG expression. Berries from VIGG-expressing grapevines had higher organic acid and phenolic contents than those from control grapevines that did not express VIGG. Interestingly, fruit composition of a grapevine that was simultaneously infected by GVA and grapevine virus B (GVB), which did not express VIGG, was significantly different from that of GVA-infected grapevines expressing VIGG, suggesting that the effector of fruit composition alteration might be VIGG expression, but not GVA infection. Taken together, VIGG expression might suppress the decrease in organic acid content and increase phenol content in berries. Further investigation of the biological function of VIGG is expected to provide new information on the fruit quality of grapevines.
authors.affiliation: Laboratory of Fruit Genetic Engineering, The Institute of Enology and Viticulture, University of Yamanashi, Kofu, Yamanashi 400-0005, Japan.
authors.forename: Hironori
authors.initials: H
authors.lastname: Katoh
authors.forename: Shunji
authors.initials: S
authors.lastname: Suzuki
authors.forename: Toshiyuki
authors.initials: T
authors.lastname: Saitoh
authors.forename: Tsutomu
authors.initials: T
authors.lastname: Takayanagi
mesh_terms: D000595:Amino Acid Sequence; D001483:Base Sequence; D002478:Cells, Cultured; D003001:Cloning, Molecular; D004721:Endoplasmic Reticulum / Q000378:metabolism; D005419:Flavonoids / Q000378:metabolism; D005638:Fruit / Q000378:metabolism* / Q000821:virology*; D018506:Gene Expression Regulation, Plant; D008969:Molecular Sequence Data; D010636:Phenols / Q000378:metabolism; D010940:Plant Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D020133:Reverse Transcriptase Polymerase Chain Reaction; D016415:Sequence Alignment; D027843:Vitis / Q000378:metabolism* / Q000821:virology*
chemical_list: D005419:Flavonoids; D010636:Phenols; D010940:Plant Proteins