title: Identification and characterization of tomato gibberellin 2-oxidases (GA2oxs) and effects of fruit-specificSlGA2ox1overexpression on fruit and seed growth and development.
abstract: Gibberellins (GAs) play a crucial role in growth and development of the tomato fruit. Previously published studies focusing on the effect of GAs on tomato fruits used chemical treatments, constitutive overexpression or silencing of GA biosynthetic and catabolic genes globally throughout the plant. Fruit-specific overexpression of GA catabolic enzyme genesGA2-oxidases(GA2oxs), however, may provide an alternative method to study the role of endogenous GAs on the fruit development. In this study, we have identified 11 SlGA2ox proteins in tomato that are classified into three subgroups. Motif analysis and multiple sequence alignments have demonstrated that all SlGA2oxs, except SlGA2ox10, have similar motif compositions and high-sequence conservation. Quantitative reverse transcription-PCR analysis has showed thatSlGA2oxsexhibit differential expression patterns in tomato fruits at different developmental stages. When the fruit-specific promoter TFM7 was used to control the expression ofSlGA2ox1, we observed no changes in growth and development of vegetative organs. However, fruit weight, seed number and germination rate were significantly affected. We also treated tomato fruits with GA biosynthesis inhibitor and observed phenotypes similar to those of the transgenic fruits. Furthermore, we have demonstrated that expression of cell expansion and GA responsive genes were downregulated in transgenic tomato fruits, supporting that overexpression of theSlGA2ox1leads to reduction in endogenous GAs. This study provides additional evidence that endogenous GAs and theSlGA2ox1gene play an important role in controlling on fruit weight, seed development and germination in tomato plant.
authors.affiliation: State Key Laboratory of Crop Genetics and Germplasm Enhancement, College of Horticulture, Nanjing Agricultural University , Nanjing 210095, China.
authors.forename: Shen
authors.initials: S
authors.lastname: Chen
authors.affiliation: State Key Laboratory of Crop Genetics and Germplasm Enhancement, College of Horticulture, Nanjing Agricultural University , Nanjing 210095, China.
authors.forename: Xiaojing
authors.initials: X
authors.lastname: Wang
authors.affiliation: College of Life Sciences, Nanjing Agricultural University , Nanjing 210095, China.
authors.forename: Liying
authors.initials: L
authors.lastname: Zhang
authors.affiliation: State Key Laboratory of Crop Genetics and Germplasm Enhancement, College of Horticulture, Nanjing Agricultural University , Nanjing 210095, China.
authors.forename: Shanshan
authors.initials: S
authors.lastname: Lin
authors.affiliation: State Key Laboratory of Crop Genetics and Germplasm Enhancement, College of Horticulture, Nanjing Agricultural University , Nanjing 210095, China.
authors.forename: Decai
authors.initials: D
authors.lastname: Liu
authors.affiliation: Jiangsu Polytechnic College of Agriculture and Forestry, Zhenjiang 212400, China; Jiangsu Engineering and Technology Center for Modern Horticulture, Zhenjiang 212400, China.
authors.forename: Quanzhi
authors.initials: Q
authors.lastname: Wang
authors.affiliation: Jiangsu Polytechnic College of Agriculture and Forestry , Zhenjiang 212400, China.
authors.forename: Shanya
authors.initials: S
authors.lastname: Cai
authors.affiliation: Department of Plant Science and Landscape Architecture, University of Connecticut , Storrs, CT 06269, USA.
authors.forename: Rania
authors.initials: R
authors.lastname: El-Tanbouly
authors.affiliation: College of Life Sciences, Nanjing Agricultural University , Nanjing 210095, China.
authors.forename: Lijun
authors.initials: L
authors.lastname: Gan
authors.affiliation: State Key Laboratory of Crop Genetics and Germplasm Enhancement, College of Horticulture, Nanjing Agricultural University , Nanjing 210095, China.
authors.forename: Han
authors.initials: H
authors.lastname: Wu
authors.affiliation: State Key Laboratory of Crop Genetics and Germplasm Enhancement, College of Horticulture, Nanjing Agricultural University, Nanjing 210095, China; Department of Plant Science and Landscape Architecture, University of Connecticut, Storrs, CT 06269, USA.
authors.forename: Yi
authors.initials: Y
authors.lastname: Li