CsAGP1, a gibberellin-responsive gene from cucumber hypocotyls, encodes a classical arabinogalactan protein and is involved in stem elongation.
Fluorescence differential display was used to isolate the gibberellin (GA)-responsive gene, CsAGP1, from cucumber (Cucumis sativus) hypocotyls. A sequence analysis of CsAGP1 indicated that the gene putatively encodes a "classical" arabinogalactan protein (AGP) in cucumber. Transgenic tobacco (Nicotiana tabacum) plants overexpressing CsAGP1 under the control of the cauliflower mosaic virus 35S promoter produced a Y(betaGlc)(3)-reactive proteoglycan in addition to AGPs present in wild-type tobacco plants. Immuno-dot blotting of the product, using anti-AGP antibodies, showed that the CsAGP1 protein had the AGP epitopes common to AGP families. The transcription level of CsAGP1 in cucumber hypocotyls increased in response not only to GA but also to indole-3-acetic acid. Although CsAGP1 is expressed in most vegetative tissues of cucumber, including the shoot apices and roots, the GA treatment resulted in an increase in the mRNA level of CsAGP1 only in the upper part of the hypocotyls. Y(betaGlc)(3), which selectively binds AGPs, inhibited the hormone-promoted elongation of cucumber seedling hypocotyls. Transgenic plants ectopically expressing CsAGP1 showed a taller stature and earlier flowering than the wild-type plants. These observations suggest that CsAGP1 is involved in stem elongation.
Park
Me Hea
MH
Department of Applied Biological Chemistry, The University of Tokyo, Bunkyo-ku, Tokyo 113-8657, Japan.
Suzuki
Yoshihito
Y
Chono
Makiko
M
Knox
J Paul
JP
Yamaguchi
Isomaro
I
D000595:Amino Acid Sequence; D000906:Antibodies; D018553:Cucumis sativus / Q000235:genetics* / Q000254:growth & development / Q000378:metabolism; D018507:Gene Expression Regulation, Developmental / Q000187:drug effects; D018506:Gene Expression Regulation, Plant / Q000187:drug effects; D005875:Gibberellins / Q000494:pharmacology*; D018546:Hypocotyl / Q000235:genetics* / Q000254:growth & development / Q000378:metabolism; D007210:Indoleacetic Acids / Q000494:pharmacology; D008969:Molecular Sequence Data; D009088:Mucoproteins / Q000235:genetics* / Q000378:metabolism; D010641:Phenotype; D010937:Plant Growth Regulators / Q000494:pharmacology*; D010940:Plant Proteins / Q000235:genetics / Q000378:metabolism; D018547:Plant Stems / Q000235:genetics / Q000254:growth & development* / Q000378:metabolism; D030821:Plants, Genetically Modified; D011509:Proteoglycans / Q000096:biosynthesis; D014026:Nicotiana / Q000235:genetics / Q000378:metabolism
D000906:Antibodies; D005875:Gibberellins; D007210:Indoleacetic Acids; D009088:Mucoproteins; D010937:Plant Growth Regulators; D010940:Plant Proteins; D011509:Proteoglycans; C030737:indoleacetic acid