title: The ARGONAUTE10 gene modulates shoot apical meristem maintenance and establishment of leaf polarity by repressing miR165/166 in Arabidopsis.
abstract: The shoot apical meristem (SAM) of angiosperms comprises a group of undifferentiated cells which divide to maintain the meristem and also give rise to all the above-ground structures of the plant. Previous studies revealed that the Arabidopsis ARGONAUTE10 [AGO10, also called PINHEAD (PNH) or ZWILLE (ZLL)] gene is one of the critical SAM regulators, but the mechanism by which AGO10 modulates the SAM is unknown. In the present study we show that AGO10 genetically represses microRNA165/166 (miR165/166) for SAM maintenance as well as establishment of leaf adaxial-abaxial polarity. Levels of miR165/166 in leaves and embryonic SAMs of pnh/zll/ago10 mutants are abnormally elevated, leading to a reduction in the quantity of homeodomain-leucine zipper (HD-ZIP) III gene transcripts, the targets of miR165/166. This reduction is the primary cause of pnh/zll SAM and leaf defects, because the aberrant pnh/zll phenotypes were partially rescued by either increasing levels of HD-ZIP III transcripts or decreasing levels of miR165/166 in the SAM and leaf. Furthermore, plants with an abnormal apex were more frequent among pnh/zll rdr6 and pnh/zll ago7 double mutants and increased levels of miR165/166 were detected in rdr6 apices. These results indicate that AGO10 and RDR6/AGO7 may act in parallel in modulating accumulation of miR165/166 for normal plant development.
authors.affiliation: National Laboratory of Plant Molecular Genetics, Shanghai Institute of Plant Physiology and Ecology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, 300 Fenglin Road, Shanghai 200032, China.
authors.forename: Qili
authors.initials: Q
authors.lastname: Liu
authors.forename: Xiaozhen
authors.initials: X
authors.lastname: Yao
authors.forename: Limin
authors.initials: L
authors.lastname: Pi
authors.forename: Hua
authors.initials: H
authors.lastname: Wang
authors.forename: Xiaofeng
authors.initials: X
authors.lastname: Cui
authors.forename: Hai
authors.initials: H
authors.lastname: Huang
mesh_terms: D017360:Arabidopsis / Q000235:genetics* / Q000254:growth & development / Q000378:metabolism; D029681:Arabidopsis Proteins / Q000235:genetics / Q000378:metabolism*; D060565:Argonaute Proteins / Q000235:genetics / Q000378:metabolism*; D016764:Cell Polarity; D003433:Crosses, Genetic; D018506:Gene Expression Regulation, Plant; D017343:Genes, Plant; D018398:Homeodomain Proteins / Q000235:genetics / Q000378:metabolism; D018519:Meristem / Q000235:genetics / Q000254:growth & development* / Q000378:metabolism; D035683:MicroRNAs / Q000235:genetics / Q000378:metabolism*; D009154:Mutation; D010641:Phenotype; D018515:Plant Leaves / Q000235:genetics / Q000254:growth & development / Q000378:metabolism; D010957:Plasmids / Q000235:genetics / Q000378:metabolism; D018749:RNA, Plant / Q000235:genetics / Q000378:metabolism*; D012097:Repressor Proteins / Q000235:genetics / Q000378:metabolism; D014170:Transformation, Genetic
chemical_list: D029681:Arabidopsis Proteins; D060565:Argonaute Proteins; D018398:Homeodomain Proteins; D035683:MicroRNAs; D018749:RNA, Plant; D012097:Repressor Proteins; C529694:AT5G43810 protein, Arabidopsis; C493946:HD-Zip protein, Arabidopsis