title: The trans-acting short interfering RNA3 pathway and no apical meristem antagonistically regulate leaf margin development and lateral organ separation, as revealed by analysis of an argonaute7/lobed leaflet1 mutant in Medicago truncatula.
abstract: Leaf shape elaboration and organ separation are critical for plant morphogenesis. We characterized the developmental roles of lobed leaflet1 by analyzing a recessive mutant in the model legume Medicago truncatula. An ortholog of Arabidopsis thaliana argonaute7 (AGO7), Mt-AGO7/lobed leaflet1, is required for the biogenesis of a trans-acting short interfering RNA (ta-siRNA) to negatively regulate the expression of auxin response factors in M. truncatula. Loss of function in AGO7 results in pleiotropic phenotypes in different organs. The prominent phenotype of the ago7 mutant is lobed leaf margins and more widely spaced lateral organs, suggesting that the trans-acting siRNA3 (TAS3) pathway negatively regulates the formation of boundaries and the separation of lateral organs in M. truncatula. Genetic interaction analysis with the smooth leaf margin1 (slm1) mutant revealed that leaf margin formation is cooperatively regulated by the auxin/SLM1 (ortholog of Arabidopsis PIN-formed1) module, which influences the initiation of leaf margin teeth, and the TAS3 ta-siRNA pathway, which determines the degree of margin indentation. Further investigations showed that the TAS3 ta-siRNA pathway and no apical meristem (ortholog of Arabidopsis cup-shaped cotyledon) antagonistically regulate both leaf margin development and lateral organ separation, and the regulation is partially dependent on the auxin/SLM1 module.
authors.affiliation: Forage Improvement Division, The Samuel Roberts Noble Foundation, Ardmore, Oklahoma 73401.
authors.forename: Chuanen
authors.initials: C
authors.lastname: Zhou
authors.forename: Lu
authors.initials: L
authors.lastname: Han
authors.forename: Chunxiang
authors.initials: C
authors.lastname: Fu
authors.forename: Jiangqi
authors.initials: J
authors.lastname: Wen
authors.forename: Xiaofei
authors.initials: X
authors.lastname: Cheng
authors.forename: Jin
authors.initials: J
authors.lastname: Nakashima
authors.forename: Junying
authors.initials: J
authors.lastname: Ma
authors.forename: Yuhong
authors.initials: Y
authors.lastname: Tang
authors.forename: Yang
authors.initials: Y
authors.lastname: Tan
authors.forename: Million
authors.initials: M
authors.lastname: Tadege
authors.forename: Kirankumar S
authors.initials: KS
authors.lastname: Mysore
authors.forename: Guangmin
authors.initials: G
authors.lastname: Xia
authors.forename: Zeng-Yu
authors.initials: ZY
authors.lastname: Wang
mesh_terms: D001483:Base Sequence; D003001:Cloning, Molecular; D035264:Flowers / Q000166:cytology / Q000235:genetics / Q000254:growth & development; D046913:Medicago truncatula / Q000166:cytology / Q000235:genetics / Q000254:growth & development*; D008969:Molecular Sequence Data; D009154:Mutation; D018515:Plant Leaves / Q000166:cytology / Q000235:genetics / Q000254:growth & development; D010940:Plant Proteins / Q000235:genetics / Q000378:metabolism / Q000502:physiology*; D034741:RNA, Small Interfering / Q000737:chemistry / Q000502:physiology*; D017423:Sequence Analysis, RNA
chemical_list: D010940:Plant Proteins; D034741:RNA, Small Interfering