title: COE1, an LRR-RLK responsible for commissural vein pattern formation in rice.
abstract: Leaf veins have a complex network pattern. Formation of this vein pattern has been widely studied as a model of tissue pattern formation in plants. To understand the molecular mechanism governing the vascular patterning process, we isolated the rice mutant, commissural vein excessive1 (coe1). The coe1 mutants had short commissural vein (CV) intervals and produced clustered CVs. Application of 1-N-naphthylphthalamic acid and brefeldin A decreased CV intervals, and application of 1-naphthaleneacetic acid increased CV intervals in wild-type rice; however, coe1 mutants were insensitive to these chemicals. COE1 encodes a leucine-rich repeat receptor-like kinase, whose amino acid sequence is similar to that of brassinosteroid-insensitive 1-associated receptor kinase 1 (BAK1), and which is localized at the plasma membrane. Because of the sequence similarity of COE1 to BAK1, we also examined the involvement of brassinosteroids in CV formation. Brassinolide, an active brassinosteroid, decreased the CV intervals of wild-type rice, and brassinazole, an inhibitor of brassinosteroid biosynthesis, increased the CV intervals of wild-type rice, but coe1 mutants showed insensitivity to these chemicals. These results suggest that auxin and brassinosteroids regulate CV intervals in opposite directions, and COE1 may regulate CV intervals downstream of auxin and brassinosteroid signals.
authors.affiliation: Department of Biological Sciences, Graduate School of Science, The University of Tokyo, Hongo 7-3-1, Bunkyo-ku, Tokyo 113-0033, JapanDepartment of Agricultural and Environmental Biology, Graduate School of Agricultural and Life Science, The University of Tokyo, Yayoi 1-1-1, Bunkyo-ku, Tokyo 113-8657, JapanGraduate School of Agricultural Science, Tohoku University, 1-1 Tsutsumidori-Amamiyamachi, Aoba-ku, Sendai 981-8555, JapanBioscience and Biotechnology Center, Nagoya University, Chikusa, Nagoya, Aichi 464-8601, Japan.
authors.forename: Jun
authors.initials: J
authors.lastname: Sakaguchi
authors.forename: Jun-Ichi
authors.initials: J
authors.lastname: Itoh
authors.forename: Yukihiro
authors.initials: Y
authors.lastname: Ito
authors.forename: Ayako
authors.initials: A
authors.lastname: Nakamura
authors.forename: Hiroo
authors.initials: H
authors.lastname: Fukuda
authors.forename: Shinichiro
authors.initials: S
authors.lastname: Sawa
mesh_terms: D060406:Brassinosteroids / Q000378:metabolism; D020126:Brefeldin A / Q000494:pharmacology; D015870:Gene Expression; D017343:Genes, Plant; D018522:Gravitropism; D007210:Indoleacetic Acids / Q000378:metabolism; D009154:Mutation; D009280:Naphthaleneacetic Acids / Q000494:pharmacology; D012275:Oryza / Q000235:genetics / Q000254:growth & development*; D010940:Plant Proteins / Q000235:genetics / Q000502:physiology*; D015398:Signal Transduction; D013260:Steroids, Heterocyclic / Q000378:metabolism
chemical_list: D060406:Brassinosteroids; D007210:Indoleacetic Acids; D009280:Naphthaleneacetic Acids; D010940:Plant Proteins; D013260:Steroids, Heterocyclic; D020126:Brefeldin A; C034182:1-naphthaleneacetic acid; C030737:indoleacetic acid; C023623:brassinolide