TCP transcription factors regulate the activities of ASYMMETRIC LEAVES1 and miR164, as well as the auxin response, during differentiation of leaves in Arabidopsis.
Coordination of the maintenance of the undifferentiated fate of cells in the shoot meristem and the promotion of cellular differentiation in plant organs is essential for the development of plant shoots. CINCINNATA-like (CIN-like) TEOSINTE BRANCHED1, CYCLOIDEA, and PCF (TCP) transcription factors are involved in this coordination via the negative regulation of CUP-SHAPED COTYLEDON (CUC) genes, which regulate the formation of shoot meristems and the specification of organ boundaries. However, the molecular mechanism of the action of CIN-like TCPs is poorly understood. We show here that TCP3, a model of CIN-like TCPs of Arabidopsis thaliana, directly activates the expression of genes for miR164, ASYMMETRIC LEAVES1 (AS1), INDOLE-3-ACETIC ACID3/SHORT HYPOCOTYL2 (IAA3/SHY2), and SMALL AUXIN UP RNA (SAUR) proteins. Gain of function of these genes suppressed the formation of shoot meristems and resulted in the fusion of cotyledons, whereas their loss of function induced ectopic expression of CUC genes in leaves. Our results indicate that miR164, AS1, IAA3/SHY2, and SAUR partially but cooperatively suppress the expression of CUC genes. Since CIN-like TCP genes were revealed to act dose dependently in the differentiation of leaves, we propose that evolutionarily diverse CIN-like TCPs have important roles in the signaling pathways that generate different leaf forms, without having any lethal effects on shoots.
Division of Integrated Life Science, Graduate School of Biostudies, Kyoto University, Oiwakecho, Kitashirakawa, Sakyo, Kyoto 606-8502, Japan. t-koyama@lif.kyoto-u.ac.jp
Tomotsugu
T
Koyama
Nobutaka
N
Mitsuda
Motoaki
M
Seki
Kazuo
K
Shinozaki
Masaru
M
Ohme-Takagi
D017360:Arabidopsis / Q000033:anatomy & histology / Q000235:genetics / Q000254:growth & development; D029681:Arabidopsis Proteins / Q000235:genetics / Q000378:metabolism*; D002454:Cell Differentiation / Q000502:physiology; D018507:Gene Expression Regulation, Developmental; D018506:Gene Expression Regulation, Plant; D007210:Indoleacetic Acids / Q000378:metabolism*; D035683:MicroRNAs / Q000235:genetics / Q000378:metabolism*; D008969:Molecular Sequence Data; D009024:Morphogenesis; D009687:Nuclear Proteins / Q000235:genetics / Q000378:metabolism; D010641:Phenotype; D018515:Plant Leaves / Q000235:genetics / Q000254:growth & development / Q000378:metabolism; D011401:Promoter Regions, Genetic; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism*
C456239:ASYMMETRIC LEAVES1 protein, Arabidopsis; D029681:Arabidopsis Proteins; D007210:Indoleacetic Acids; C538852:MIRN164 microRNA, Arabidopsis; D035683:MicroRNAs; D009687:Nuclear Proteins; C086789:SAUR-AC1 protein, Arabidopsis; C117994:SHY2 protein, Arabidopsis; D014157:Transcription Factors