title: Over-expression of OsPIN2 leads to increased tiller numbers, angle and shorter plant height through suppression of OsLAZY1.
abstract: Crop architecture parameters such as tiller number, angle and plant height are important agronomic traits that have been considered for breeding programmes. Auxin distribution within the plant has long been recognized to alter architecture. The rice (Oryza sativa L.) genome contains 12 putative PIN genes encoding auxin efflux transporters, including four PIN1 and one PIN2 genes. Here, we report that over-expression of OsPIN2 through a transgenic approach in rice (Japonica cv. Nipponbare) led to a shorter plant height, more tillers and a larger tiller angle when compared with wild type (WT). The expression patterns of the auxin reporter DR5::GUS and quantification of auxin distribution showed that OsPIN2 over-expression increased auxin transport from the shoot to the root-shoot junction, resulting in a non-tissue-specific accumulation of more free auxin at the root-shoot junction relative to WT. Over-expression of OsPIN2 enhanced auxin transport from shoots to roots, but did not alter the polar auxin pattern in the roots. Transgenic plants were less sensitive to N-1-naphthylphthalamic acid, an auxin transport inhibitor, than WT in their root growth. OsPIN2-over-expressing plants had suppressed the expression of a gravitropism-related gene OsLazy1 in the shoots, but unaltered expression of OsPIN1b and OsTAC1, which were reported as tiller angle controllers in rice. The data suggest that OsPIN2 has a distinct auxin-dependent regulation pathway together with OsPIN1b and OsTAC1 controlling rice shoot architecture. Altering OsPIN2 expression by genetic transformation can be directly used for modifying rice architecture.
authors.affiliation: State Key Laboratory of Crop Genetics and Germplasm Enhancement, College of Resources and Environmental Sciences, Nanjing Agricultural University, Nanjing, China.
authors.forename: Yingnan
authors.initials: Y
authors.lastname: Chen
authors.forename: Xiaorong
authors.initials: X
authors.lastname: Fan
authors.forename: Wenjing
authors.initials: W
authors.lastname: Song
authors.forename: Yali
authors.initials: Y
authors.lastname: Zhang
authors.forename: Guohua
authors.initials: G
authors.lastname: Xu
mesh_terms: D001692:Biological Transport; D018506:Gene Expression Regulation, Plant; D017343:Genes, Plant; D018522:Gravitropism / Q000235:genetics; D007210:Indoleacetic Acids / Q000378:metabolism; D012275:Oryza / Q000033:anatomy & histology / Q000235:genetics* / Q000254:growth & development* / Q000378:metabolism; D010797:Phthalimides / Q000378:metabolism; D010937:Plant Growth Regulators / Q000378:metabolism; D010940:Plant Proteins / Q000096:biosynthesis / Q000235:genetics*; D018517:Plant Roots / Q000235:genetics / Q000254:growth & development; D018520:Plant Shoots / Q000235:genetics / Q000254:growth & development; D030821:Plants, Genetically Modified; D035321:Telomeric Repeat Binding Protein 1 / Q000096:biosynthesis / Q000235:genetics*
chemical_list: D007210:Indoleacetic Acids; D010797:Phthalimides; D010937:Plant Growth Regulators; D010940:Plant Proteins; D035321:Telomeric Repeat Binding Protein 1; C002687:alpha-naphthylphthalamic acid