title: Ectopic expression a tomato KNOX Gene Tkn4 affects the formation and the differentiation of meristems and vasculature.
abstract: The KNOTTED-LIKE HOMEODOMAIN genes are involved in maintenance of the shoot apical meristem which produces the whole above-ground body of vascular plants. In this report, a tomato homolog gene, named as Tkn4 (a nucleus targeted transcription factor) was identified and characterized. By performing RT-PCR, the transcript level of Tkn4 was separately found in stem, root, stamen, stigma, fruit and sepal but hardly visible in the leaf. Besides, Tkn4 was induced by a series of plant hormones. Overexpression of Tkn4 gene in tomato resulted in dwarf phenotype and strongly repressed the formation of shoot apical meristem, lateral meristem and cambiums in transgenic lines. The transgenic lines had wrinkled leaves and anatomic analysis showed that there was no obvious palisade tissues in the leaves and the layer of cells changed in vascular tissue (xylem and phloem). To explore the regulation network of Tkn4, RNA-sequencing was performed in overexpression lines and wild type plants, by which many genes related to the synthesis and the signal transduction of cytokinin, auxin, gibberellin, ethylene, abscisic acid, and tracheary element differentiation or extracellular matrix synthesis were significantly regulated. Taken together, our results demonstrate that Tkn4 plays important roles in regulating the biosynthesis and signal transduction of diverse plant hormones, and the formation and differentiation of meristems and vasculature in tomato.
authors.affiliation: Genetic Engineering Research Center, School of Life Sciences, Key Laboratory of Functional Gene and Regulation Technologies under Chongqing Municipal Education Commission, Chongqing University, Chongqing, 400044, People's Republic of China.
authors.forename: Fang
authors.initials: F
authors.lastname: Yan
authors.affiliation: Genetic Engineering Research Center, School of Life Sciences, Key Laboratory of Functional Gene and Regulation Technologies under Chongqing Municipal Education Commission, Chongqing University, Chongqing, 400044, People's Republic of China.
authors.forename: Guojian
authors.initials: G
authors.lastname: Hu
authors.affiliation: Genetic Engineering Research Center, School of Life Sciences, Key Laboratory of Functional Gene and Regulation Technologies under Chongqing Municipal Education Commission, Chongqing University, Chongqing, 400044, People's Republic of China.
authors.forename: Zhenxin
authors.initials: Z
authors.lastname: Ren
authors.affiliation: Genetic Engineering Research Center, School of Life Sciences, Key Laboratory of Functional Gene and Regulation Technologies under Chongqing Municipal Education Commission, Chongqing University, Chongqing, 400044, People's Republic of China. dengwei1977@cqu.edu.cn.
authors.forename: Wei
authors.initials: W
authors.lastname: Deng
authors.affiliation: Genetic Engineering Research Center, School of Life Sciences, Key Laboratory of Functional Gene and Regulation Technologies under Chongqing Municipal Education Commission, Chongqing University, Chongqing, 400044, People's Republic of China. zhengguoli@cqu.edu.cn.
authors.forename: Zhengguo
authors.initials: Z
authors.lastname: Li
mesh_terms: D000595:Amino Acid Sequence; D003001:Cloning, Molecular; D015870:Gene Expression; D017343:Genes, Plant; D018551:Solanum lycopersicum / Q000235:genetics* / Q000254:growth & development* / Q000378:metabolism; D018519:Meristem / Q000235:genetics / Q000254:growth & development / Q000378:metabolism; D008969:Molecular Sequence Data; D010641:Phenotype; D010802:Phylogeny; D010937:Plant Growth Regulators / Q000235:genetics / Q000378:metabolism; D010940:Plant Proteins / Q000235:genetics / Q000378:metabolism; D058526:Plant Vascular Bundle / Q000235:genetics / Q000254:growth & development / Q000378:metabolism; D030821:Plants, Genetically Modified; D017386:Sequence Homology, Amino Acid; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism; D015854:Up-Regulation
chemical_list: D010937:Plant Growth Regulators; D010940:Plant Proteins; D014157:Transcription Factors
keywords: Hormone; Meristem; Tkn4; Tomato; Transgenetic; Vascular