title: miR396a-Mediated basic helix-loop-helix transcription factor bHLH74 repression acts as a regulator for root growth in Arabidopsis seedlings.
abstract: miR396 targets seven GROWTH-REGULATING FACTOR (GRF) genes and the BASIC HELIX-LOOP-HELIX (bHLH) TRANSCRIPTION FACTOR 74 gene (bHLH74) in Arabidopsis. Previous research revealed that the miR396 target module regulates cell proliferation and plays a critical role in leaf development. However, no additional biological functions of miR396 have been investigated in detail. In this study, T-DNA insertion mutants and transgenic plants with altered levels of miR396 or its target genes were used to characterize the regulatory role of miR396 in root development. We found that AtMIR396a was the predominant source for miR396 accumulation in the roots of seedlings, and that the mir396a-1 mutant had longer roots than wild-type seedlings. Overexpression of AtMIR396a decreased the transcript levels of target genes such as GRF genes and bHLH74, and resulted in a shorter root phenotype. Furthermore, the bhlh74-1 mutant had shorter roots, whereas overexpression of an miR396-resistant form of bHLH74 (mbHLH74) had an enhanced root growth phenotype. Moreover, MIR396a regulated root growth by affecting the elongation zone. Taken together, these data indicate that miR396a-mediated bHLH74 repression helps regulate root growth in Arabidopsis seedlings.
authors.affiliation: Key Laboratory for Cell and Gene Engineering of Zhejiang Province, Institute of Genetics, College of Life Sciences, Zhejiang University, Hangzhou 310058, Zhejiang, China.
authors.forename: Maolin
authors.initials: M
authors.lastname: Bao
authors.affiliation: Key Laboratory for Cell and Gene Engineering of Zhejiang Province, Institute of Genetics, College of Life Sciences, Zhejiang University, Hangzhou 310058, Zhejiang, China.
authors.forename: Hongwu
authors.initials: H
authors.lastname: Bian
authors.affiliation: Key Laboratory for Cell and Gene Engineering of Zhejiang Province, Institute of Genetics, College of Life Sciences, Zhejiang University, Hangzhou 310058, Zhejiang, China.
authors.forename: Yulong
authors.initials: Y
authors.lastname: Zha
authors.affiliation: Key Laboratory for Cell and Gene Engineering of Zhejiang Province, Institute of Genetics, College of Life Sciences, Zhejiang University, Hangzhou 310058, Zhejiang, China.
authors.forename: Fengyun
authors.initials: F
authors.lastname: Li
authors.affiliation: Key Laboratory for Cell and Gene Engineering of Zhejiang Province, Institute of Genetics, College of Life Sciences, Zhejiang University, Hangzhou 310058, Zhejiang, China.
authors.forename: Yuzhe
authors.initials: Y
authors.lastname: Sun
authors.affiliation: Key Laboratory for Cell and Gene Engineering of Zhejiang Province, Institute of Genetics, College of Life Sciences, Zhejiang University, Hangzhou 310058, Zhejiang, China.
authors.forename: Bin
authors.initials: B
authors.lastname: Bai
authors.affiliation: Key Laboratory for Cell and Gene Engineering of Zhejiang Province, Institute of Genetics, College of Life Sciences, Zhejiang University, Hangzhou 310058, Zhejiang, ChinaCollege of Life and Environmental Sciences, Hangzhou Normal University, Hangzhou, 310036, Zhejiang, China.
authors.forename: Zhehao
authors.initials: Z
authors.lastname: Chen
authors.affiliation: Key Laboratory for Cell and Gene Engineering of Zhejiang Province, Institute of Genetics, College of Life Sciences, Zhejiang University, Hangzhou 310058, Zhejiang, China.
authors.forename: Junhui
authors.initials: J
authors.lastname: Wang
authors.affiliation: Key Laboratory for Cell and Gene Engineering of Zhejiang Province, Institute of Genetics, College of Life Sciences, Zhejiang University, Hangzhou 310058, Zhejiang, China.
authors.forename: Muyuan
authors.initials: M
authors.lastname: Zhu
authors.affiliation: Key Laboratory for Cell and Gene Engineering of Zhejiang Province, Institute of Genetics, College of Life Sciences, Zhejiang University, Hangzhou 310058, Zhejiang, China ninghan@zju.edu.cn.
authors.forename: Ning
authors.initials: N
authors.lastname: Han
mesh_terms: D017360:Arabidopsis / Q000166:cytology / Q000235:genetics* / Q000254:growth & development / Q000378:metabolism; D029681:Arabidopsis Proteins / Q000235:genetics* / Q000378:metabolism; D051792:Basic Helix-Loop-Helix Proteins / Q000235:genetics* / Q000378:metabolism; D015870:Gene Expression; D018506:Gene Expression Regulation, Plant; D017930:Genes, Reporter; D035683:MicroRNAs / Q000235:genetics*; D018517:Plant Roots / Q000166:cytology / Q000235:genetics / Q000254:growth & development / Q000378:metabolism; D030821:Plants, Genetically Modified; D036226:Seedlings / Q000166:cytology / Q000235:genetics / Q000254:growth & development / Q000378:metabolism
chemical_list: D029681:Arabidopsis Proteins; D051792:Basic Helix-Loop-Helix Proteins; D035683:MicroRNAs; C572930:MIRN396 microRNA, Arabidopsis; C572931:bHLH74 protein, Arabidopsis
keywords: Arabidopsis thaliana; Basic helix–loop–helix (bHLH) transcription factor 74 (bHLH74); Growth-regulating factor (GRF); Root growth; miRNA396