Abstract
N-1-Naphthylphthalamic acid (NPA) causes the abnormal growth and development of plants by suppressing polar auxin transport. The mechanisms underlying this inhibition, however, have remained elusive. In Arabidopsis, we show that a defect in the ABC subfamily B auxin transporter AtABCB19 suppresses the inhibitory effects of NPA on hypocotyl phototropism and gravitropism, but not on hypocotyl elongation. Expression analysis using the auxin reporter gene DR5:GUS further suggests that NPA partially inhibits the asymmetric distribution of auxin in an AtABCB19-dependent manner. These data thus suggest that AtABCB19 plays an important role in the inhibitory effects of NPA on hypocotyl tropism induced by auxin.
Publication types
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Research Support, Non-U.S. Gov't
MeSH terms
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ATP-Binding Cassette Transporters / genetics
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ATP-Binding Cassette Transporters / metabolism*
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Arabidopsis / metabolism*
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Arabidopsis Proteins / genetics
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Arabidopsis Proteins / metabolism*
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Carrier Proteins / genetics
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Carrier Proteins / metabolism
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Dose-Response Relationship, Drug
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Gene Expression Regulation, Plant / physiology
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Gravitropism / drug effects*
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Hypocotyl / drug effects
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Hypocotyl / growth & development*
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Hypocotyl / metabolism
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Phototropism / drug effects*
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Phthalimides / pharmacology*
Substances
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ABCB19 protein, Arabidopsis
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ATP-Binding Cassette Transporters
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Arabidopsis Proteins
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Carrier Proteins
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Phthalimides
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alpha-naphthylphthalamic acid