Control of root cap formation by MicroRNA-targeted auxin response factors in Arabidopsis.
The plant root cap mediates the direction of root tip growth and protects internal cells. Root cap cells are continuously produced from distal stem cells, and the phytohormone auxin provides position information for root distal organization. Here, we identify the Arabidopsis thaliana auxin response factors ARF10 and ARF16, targeted by microRNA160 (miR160), as the controller of root cap cell formation. The Pro(35S):MIR160 plants, in which the expression of ARF10 and ARF16 is repressed, and the arf10-2 arf16-2 double mutants display the same root tip defect, with uncontrolled cell division and blocked cell differentiation in the root distal region and show a tumor-like root apex and loss of gravity-sensing. ARF10 and ARF16 play a role in restricting stem cell niche and promoting columella cell differentiation; although functionally redundant, the two ARFs are indispensable for root cap development, and the auxin signal cannot bypass them to initiate columella cell production. In root, auxin and miR160 regulate the expression of ARF10 and ARF16 genes independently, generating a pattern consistent with root cap development. We further demonstrate that miR160-uncoupled production of ARF16 exerts pleiotropic effects on plant phenotypes, and miR160 plays an essential role in regulating Arabidopsis development and growth.
Wang
Jia-Wei
JW
National Key Laboratory of Plant Molecular Genetics, Institute of Plant Physiology and Ecology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 200032, People's Republic of China.
Wang
Ling-Jian
LJ
Mao
Ying-Bo
YB
Cai
Wen-Juan
WJ
Xue
Hong-Wei
HW
Chen
Xiao-Ya
XY
D017360:Arabidopsis / Q000235:genetics*; D029681:Arabidopsis Proteins / Q000235:genetics*; D001483:Base Sequence; D018506:Gene Expression Regulation, Plant; D007210:Indoleacetic Acids / Q000502:physiology*; D035683:MicroRNAs / Q000235:genetics*; D016254:Mutagenesis, Insertional; D018517:Plant Roots / Q000502:physiology*; D018749:RNA, Plant / Q000235:genetics*; D014157:Transcription Factors / Q000235:genetics*
C505216:ARF10 protein, Arabidopsis; C505217:ARF16 protein, Arabidopsis; D029681:Arabidopsis Proteins; D007210:Indoleacetic Acids; D035683:MicroRNAs; D018749:RNA, Plant; D014157:Transcription Factors