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LKP1 (LOV kelch protein 1): a factor involved in the regulation of flowering time in Arabidopsis
Author(s) -
Kiyosue Tomohiro,
Wada Masamitsu
Publication year - 2000
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 - 10.1046/j.1365-313x.2000.00850.x
Subject(s) - arabidopsis , biology , silique , cotyledon , complementary dna , transgene , microbiology and biotechnology , phototropism , ectopic expression , fusion protein , gene , green fluorescent protein , hypocotyl , genetically modified crops , vernalization , arabidopsis thaliana , botany , genetics , mutant , physics , optics , blue light , recombinant dna
Summary In plants, light is not only an energy source but also a very important signal that modulates development and differentiation. Here, we report a putative photo‐regulatory factor sequence in LKP1 (LOV kelch protein 1). LKP1 cDNA encodes a protein of 610 amino acids and with a molecular weight of 65 905 with an LOV domain and kelch repeats. LOV domains are present in a number of sensor proteins involved in the detection of light, oxygen or voltage. The LKP1 LOV is very similar to the LOV domains in NPH1, a plasma membrane‐associated blue light receptor kinase that regulates phototropism (Huala, E., Oeller, P.W., Liscum, E., Han, I‐S., Larsen, E. & Briggs, W.R. (1997) Science , 278, 2120–2123). LKP1 mRNA accumulates in roots, stems, flowers and siliques. It is most abundant in leaves, and least abundant in seeds. Transgenic plants with a β‐glucuronidase (GUS) reporter gene driven by a 1.5 kb LKP1 promoter display strong GUS activity in leaves. Transgenic plants with a 35S::LKP1 cDNA gene overexpress LKP1 mRNA. These plants have elongated hypocotyls and petioles with elongated cells, and exhibit distinct cotyledon movement during the day. Expression of 35S::LKP1 in transgenic Arabidopsis promotes late flowering in plants grown under long‐day, but not under short‐day conditions. Vernalization does not affect the late flowering phenotype of the 35S::LKP1 plants. Transgenic plants possessing the 35S::GFP‐LKP1 construct also have long hypocotyles and petioles, and a late flowering phenotype, suggesting that the GFP‐LKP1 fusion protein is active. The GFP‐associated fluorescence in 35S::GFP‐LKP1 plants is observed in nuclei and cytosol, indicating that LKP1 is a new nucleo‐cytoplasmic factor that influences flowering time in the long day pathway of Arabidopsis.