title: Suppression of extracellular invertase inhibitor gene expression improves seed weight in soybean (Glycine max).
abstract: Cell wall invertase (CWI) and vacuolar invertase (VI) play multiple functions in plant growth. As well as depending on transcriptional and post-transcriptional regulation, there is growing evidence that CWI and VI are also subject to post-translational control by small inhibitory proteins. Despite the significance of this, genes encoding inhibitors, their molecular and biochemical properties, and their potential roles in regulating seed production have not been well documented in soybean (Glycine max). In this study, two invertase inhibitor isoforms, GmCIF1 and GmC/VIF2, were characterized to possess inhibitory activities in vitro via heterologous expression. Transcript analyses showed that they were predominantly expressed in developing seeds and in response to ABA. In accordance with this, surveys of primary targets showed subcellular localizations to the apoplast in tobacco epidermis after expressing YFP-fusion constructs. Investigations using RNAi transgenic plants demonstrated marked elevations of CWI activities and improvements in seed weight in conjunction with higher accumulations of hexoses, starch, and protein in mature seeds. Further co-expression analyses of GmCIF1 with several putative CWI genes corroborated the notion that GmCIF1 modulation of CWI that affects seed weight is mainly contingent on post-translational mechanisms. Overall, the results suggest that post-translational elevation of CWI by silencing of GmCIF1 expression orchestrates the process of seed maturation through fine-tuning sucrose metabolism and sink strength.
authors.affiliation: Soybean Research Institute, Academy of Agricultural Sciences, Harbin, China.|Plant Molecular Physiology, Centre for Organismal Studies (COS), Heidelberg University, Im Neuenheimer Feld, Heidelberg, Germany.
authors.forename: Xiaofei
authors.initials: X
authors.lastname: Tang
authors.affiliation: Co-Innovation Center for Sustainable Forestry in Southern China, College of Biology and Environment, Nanjing Forestry University, Nanjing, China.|Plant Molecular Physiology, Centre for Organismal Studies (COS), Heidelberg University, Im Neuenheimer Feld, Heidelberg, Germany.
authors.forename: Tao
authors.initials: T
authors.lastname: Su
authors.affiliation: Co-Innovation Center for Sustainable Forestry in Southern China, College of Biology and Environment, Nanjing Forestry University, Nanjing, China.
authors.forename: Mei
authors.initials: M
authors.lastname: Han
authors.affiliation: Soybean Research Institute, Academy of Agricultural Sciences, Harbin, China.
authors.forename: Lai
authors.initials: L
authors.lastname: Wei
authors.affiliation: Soybean Research Institute, Academy of Agricultural Sciences, Harbin, China.
authors.forename: Weiwei
authors.initials: W
authors.lastname: Wang
authors.affiliation: Soybean Research Institute, Academy of Agricultural Sciences, Harbin, China.
authors.forename: Zhiyuan
authors.initials: Z
authors.lastname: Yu
authors.affiliation: Soybean Research Institute, Academy of Agricultural Sciences, Harbin, China.
authors.forename: Yongguo
authors.initials: Y
authors.lastname: Xue
authors.affiliation: Plant Molecular Physiology, Centre for Organismal Studies (COS), Heidelberg University, Im Neuenheimer Feld, Heidelberg, Germany.
authors.forename: Hongbin
authors.initials: H
authors.lastname: Wei
authors.affiliation: Plant Molecular Physiology, Centre for Organismal Studies (COS), Heidelberg University, Im Neuenheimer Feld, Heidelberg, Germany.
authors.forename: Yejie
authors.initials: Y
authors.lastname: Du
authors.affiliation: Plant Molecular Physiology, Centre for Organismal Studies (COS), Heidelberg University, Im Neuenheimer Feld, Heidelberg, Germany.
authors.forename: Steffen
authors.initials: S
authors.lastname: Greiner
authors.affiliation: Plant Molecular Physiology, Centre for Organismal Studies (COS), Heidelberg University, Im Neuenheimer Feld, Heidelberg, Germany.
authors.forename: Thomas
authors.initials: T
authors.lastname: Rausch
authors.affiliation: Soybean Research Institute, Academy of Agricultural Sciences, Harbin, China.
authors.forename: Lijun
authors.initials: L
authors.lastname: Liu
mesh_terms: D000595:Amino Acid Sequence; D018506:Gene Expression Regulation, Plant; D010940:Plant Proteins / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D012639:Seeds / Q000502:physiology*; D016415:Sequence Alignment; D013025:Glycine max / Q000235:genetics / Q000502:physiology*; D043324:beta-Fructofuranosidase / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism
chemical_list: D010940:Plant Proteins; D043324:beta-Fructofuranosidase
keywords: Cell wall invertase; Glycine max; invertase inhibitor; post-translational regulation; seed weight; source and sink