title: Developmental analysis of a Medicago truncatula smooth leaf margin1 mutant reveals context-dependent effects on compound leaf development.
abstract: Compound leaf development requires highly regulated cell proliferation, differentiation, and expansion patterns. We identified loss-of-function alleles at the SMOOTH LEAF MARGIN1 (SLM1) locus in Medicago truncatula, a model legume species with trifoliate adult leaves. SLM1 encodes an auxin efflux carrier protein and is the ortholog of Arabidopsis thaliana PIN-FORMED1 (PIN1). Auxin distribution is impaired in the slm1 mutant, resulting in pleiotropic phenotypes in different organs. The most striking change in slm1 is the increase in the number of terminal leaflets and a simultaneous reduction in the number of lateral leaflets, accompanied by reduced expression of SINGLE LEAFLET1 (SGL1), an ortholog of LEAFY. Characterization of the mutant indicates that distinct developmental domains exist in the formation of terminal and lateral leaflets. In contrast with the pinnate compound leaves in the wild type, the slm1 sgl1 double mutant shows nonpeltately palmate leaves, suggesting that the terminal leaflet primordium in M. truncatula has a unique developmental mechanism. Further investigations on the development of leaf serrations reveal different ontogenies between distal serration and marginal serration formation as well as between serration and leaflet formation. These data suggest that regulation of the elaboration of compound leaves and serrations is context dependent and tightly correlated with the auxin/SLM1 module in M. truncatula.
authors.affiliation: Forage Improvement Division, Samuel Roberts Noble Foundation, Ardmore, Oklahoma 73401, USA.
authors.forename: Chuanen
authors.initials: C
authors.lastname: Zhou
authors.forename: Lu
authors.initials: L
authors.lastname: Han
authors.forename: Chunyan
authors.initials: C
authors.lastname: Hou
authors.forename: Alessandra
authors.initials: A
authors.lastname: Metelli
authors.forename: Liying
authors.initials: L
authors.lastname: Qi
authors.forename: Million
authors.initials: M
authors.lastname: Tadege
authors.forename: Kirankumar S
authors.initials: KS
authors.lastname: Mysore
authors.forename: Zeng-Yu
authors.initials: ZY
authors.lastname: Wang
mesh_terms: D029681:Arabidopsis Proteins / Q000235:genetics / Q000378:metabolism; D035264:Flowers / Q000254:growth & development; D018506:Gene Expression Regulation, Plant; D017343:Genes, Plant; D005816:Genetic Complementation Test; D007210:Indoleacetic Acids / Q000378:metabolism; D046913:Medicago truncatula / Q000033:anatomy & histology* / Q000235:genetics* / Q000254:growth & development* / Q000378:metabolism; D026901:Membrane Transport Proteins / Q000235:genetics / Q000378:metabolism; D046228:Microarray Analysis; D008969:Molecular Sequence Data; D009154:Mutation; D010641:Phenotype; D018515:Plant Leaves / Q000033:anatomy & histology* / Q000235:genetics* / Q000254:growth & development* / Q000378:metabolism; D010940:Plant Proteins / Q000235:genetics* / Q000378:metabolism; D030821:Plants, Genetically Modified; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism
chemical_list: D029681:Arabidopsis Proteins; D007210:Indoleacetic Acids; C074747:LFY protein, Arabidopsis; D026901:Membrane Transport Proteins; C116363:PIN1 protein, Arabidopsis; D010940:Plant Proteins; D014157:Transcription Factors