title: Overexpression of β-expansin gene GmEXPB2 improves phosphorus efficiency in soybean.
abstract: Soybean (Glycine max) is an important oil crop in agricultural production, but low phosphorus (P) availability limits soybean growth and production. Expansin is a family of plant cell wall proteins and involved in a variety of physiological processes, including cell division and enlargement, root growth and leaf development. To test the potential effects of expansins on crop production, we have developed soybean transgenic plants overexpressing a soybean β-expansin gene GmEXPB2, which was significantly induced by phosphate (Pi) starvation. The results indicated that constitutive overexpression of GmEXPB2 promoted leaf expansion, sequentially stimulated root growth and consequently resulted in improved P efficiency in the transgenic plants under P-limited conditions in hydroponics. In particular, when tested in calcareous (CS) and acid soils (AS), the two GmEXPB2 transgenic soybean lines showed above 25 and 40% increases in plant dry weight and P content, respectively to wild-type plants in low-P CS, but not in AS. To our knowledge, this is the first report in which improvement of P efficiency could be achieved through constitutive overexpression of an endogenous EXPB gene in soybean. These findings suggest that genetic modification of root and leaf traits might be a suitable strategy for improving crop production in low-P soils.
authors.affiliation: State Key Laboratory for Conservation and Utilization of Subtropical Agro-bioresources, Root Biology Center, South China Agricultural University, Guangzhou, 510642, China.
authors.forename: Jia
authors.initials: J
authors.lastname: Zhou
authors.forename: Jianna
authors.initials: J
authors.lastname: Xie
authors.forename: Hong
authors.initials: H
authors.lastname: Liao
authors.forename: Xiurong
authors.initials: X
authors.lastname: Wang
mesh_terms: D018533:Biomass; D018506:Gene Expression Regulation, Plant / Q000187:drug effects; D017343:Genes, Plant / Q000235:genetics*; D018527:Hydroponics; D010758:Phosphorus / Q000172:deficiency* / Q000494:pharmacology; D018515:Plant Leaves / Q000187:drug effects / Q000235:genetics; D010940:Plant Proteins / Q000235:genetics* / Q000378:metabolism; D018517:Plant Roots / Q000187:drug effects / Q000235:genetics; D030821:Plants, Genetically Modified; D019655:Quantitative Trait, Heritable; D012639:Seeds / Q000187:drug effects / Q000378:metabolism; D013025:Glycine max / Q000187:drug effects / Q000235:genetics* / Q000254:growth & development
chemical_list: D010940:Plant Proteins; C095825:expansin protein, plant; D010758:Phosphorus