title: A complex case of simple leaves: indeterminate leaves co-express ARP and KNOX1 genes.
abstract: The mutually exclusive relationship between ARP and KNOX1 genes in the shoot apical meristem and leaf primordia in simple leaved plants such as Arabidopsis has been well characterized. Overlapping expression domains of these genes in leaf primordia have been described for many compound leaved plants such as Solanum lycopersicum and Cardamine hirsuta and are regarded as a characteristic of compound leaved plants. Here, we present several datasets illustrating the co-expression of ARP and KNOX1 genes in the shoot apical meristem, leaf primordia, and developing leaves in plants with simple leaves and simple primordia. Streptocarpus plants produce unequal cotyledons due to the continued activity of a basal meristem and produce foliar leaves termed "phyllomorphs" from the groove meristem in the acaulescent species Streptocarpus rexii and leaves from a shoot apical meristem in the caulescent Streptocarpus glandulosissimus. We demonstrate that the simple leaves in both species possess a greatly extended basal meristematic activity that persists over most of the leaf's growth. The area of basal meristem activity coincides with the co-expression domain of ARP and KNOX1 genes. We suggest that the co-expression of ARP and KNOX1 genes is not exclusive to compound leaved plants but is associated with foci of meristematic activity in leaves.
authors.affiliation: Institute of Ecology and Evolutionary Biology, Department of Life Science, National Taiwan University, No. 1 Sec. 4 Roosevelt Road, Taipei, Taiwan, Republic of China. kanaenishii@ntu.edu.tw
authors.forename: Kanae
authors.initials: K
authors.lastname: Nishii
authors.forename: Michael
authors.initials: M
authors.lastname: Möller
authors.forename: Catherine
authors.initials: C
authors.lastname: Kidner
authors.forename: Alberto
authors.initials: A
authors.lastname: Spada
authors.forename: Raffaella
authors.initials: R
authors.lastname: Mantegazza
authors.forename: Chun-Neng
authors.initials: CN
authors.lastname: Wang
authors.forename: Toshiyuki
authors.initials: T
authors.lastname: Nagata
mesh_terms: D000595:Amino Acid Sequence; D031217:Cardamine / Q000235:genetics / Q000254:growth & development; D018506:Gene Expression Regulation, Plant; D017343:Genes, Plant; D018398:Homeodomain Proteins / Q000235:genetics*; D018519:Meristem / Q000235:genetics* / Q000254:growth & development / Q000378:metabolism; D008969:Molecular Sequence Data; D018515:Plant Leaves / Q000235:genetics* / Q000254:growth & development / Q000378:metabolism; D010940:Plant Proteins / Q000235:genetics*
chemical_list: D018398:Homeodomain Proteins; C405985:Knox1 protein, plant; D010940:Plant Proteins