title: Dof5.6/HCA2, a Dof transcription factor gene, regulates interfascicular cambium formation and vascular tissue development in Arabidopsis.
abstract: Vascular cambium, a type of lateral meristem, is the source of secondary xylem and secondary phloem, but little is known about the molecular mechanisms of its formation and development. Here, we report the characterization of an Arabidopsis thaliana gain-of-function mutant with dramatically increased cambial activity, designated high cambial activity2 (hca2). The hca2 mutant has no alternative organization of the vascular bundles/fibers in inflorescence stems, due to precocious formation of interfascicular cambium and its subsequent cell division. The phenotype results from elevated expression of HCA2, which encodes a nuclear-localized DNA binding with one finger (Dof) transcription factor Dof5.6. Dof5.6/HCA2 is preferentially expressed in the vasculature of all the organs, particularly in the cambium, phloem, and interfascicular parenchyma cells of inflorescence stems. Dominant-negative analysis further demonstrated that both ubiquitous and in situ repression of HCA2 activity led to disruption of interfascicular cambium formation and development in inflorescence stems. In-depth anatomical analysis showed that HCA2 promotes interfascicular cambium formation at a very early stage of inflorescence stem development. This report demonstrates that a transcription factor gene, HCA2, is involved in regulation of interfascicular cambium formation and vascular tissue development in Arabidopsis.
authors.affiliation: National Laboratory for Protein Engineering and Plant Genetic Engineering, College of Life Sciences, Peking University, Beijing, People's Republic of China.
authors.forename: Yong
authors.initials: Y
authors.lastname: Guo
authors.forename: Genji
authors.initials: G
authors.lastname: Qin
authors.forename: Hongya
authors.initials: H
authors.lastname: Gu
authors.forename: Li-Jia
authors.initials: LJ
authors.lastname: Qu
mesh_terms: D017360:Arabidopsis / Q000235:genetics* / Q000254:growth & development* / Q000378:metabolism; D029681:Arabidopsis Proteins / Q000235:genetics* / Q000302:isolation & purification / Q000378:metabolism; D019521:Body Patterning / Q000235:genetics*; D002454:Cell Differentiation / Q000235:genetics; D002467:Cell Nucleus / Q000235:genetics / Q000378:metabolism; D004268:DNA-Binding Proteins / Q000235:genetics / Q000378:metabolism; D018506:Gene Expression Regulation, Plant / Q000235:genetics; D036341:Intercellular Signaling Peptides and Proteins / Q000235:genetics / Q000378:metabolism; D018519:Meristem / Q000235:genetics / Q000254:growth & development / Q000378:metabolism; D014157:Transcription Factors / Q000235:genetics* / Q000302:isolation & purification / Q000378:metabolism; D015533:Transcriptional Activation / Q000235:genetics
chemical_list: D029681:Arabidopsis Proteins; C407526:DAG1 protein, Arabidopsis; D004268:DNA-Binding Proteins; C547878:HCA2 protein, Arabidopsis; D036341:Intercellular Signaling Peptides and Proteins; D014157:Transcription Factors