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COE1, an LRR–RLK responsible for commissural vein pattern formation in rice
Author(s) -
Sakaguchi Jun,
Itoh JunIchi,
Ito Yukihiro,
Nakamura Ayako,
Fukuda Hiroo,
Sawa Shinichiro
Publication year - 2010
Publication title -
the plant journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.058
H-Index - 269
eISSN - 1365-313X
pISSN - 0960-7412
DOI - 10.1111/j.1365-313x.2010.04250.x
Subject(s) - brassinosteroid , mutant , auxin , biology , wild type , brassinolide , microbiology and biotechnology , botany , biochemistry , genetics , arabidopsis , gene , plant growth
Summary 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.