Abstract
We previously isolated a rhizobacterium (Bacillus subtilis IJ-31) and demonstrated that its associated allelochemicals could indicate plant growth retardation. However, little is known about how the growth of plants is regulated by B. subtilis IJ-31 and its allelochemicals. In this study, we investigated whether plant growth retardation in this relationship occurred through the inhibition of gibberellin (GA) biosynthesis. GA 3beta-hydroxylase activity was found to be inhibited by B. subtilis IJ-31 and hydrocinnamic acid (HCA), which is one of the allelochemicals produced by B. subtilis IJ-31. Additionally, thin layer chromatography (TLC) demonstrated that B. subtilis IJ-31 culture broth and HCA both inhibit GA 3beta-hydroxylase (MBP-GA4) activity. The retardation of plants by HCA was then confirmed in vivo and in vitro using a Ryegrass and Arabidopsis growth retardation assay. Furthermore, treatment with either B. subtilis IJ-31 culture extract or its allelochemicals resulted in significant down-regulation of XTR9 gene expression in Arabidopsis. Overall, we identified the functional mechanism of plant growth retardation by B. subtilis IJ-31 and its allelochemicals.
MeSH terms
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Arabidopsis / drug effects*
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Arabidopsis / enzymology
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Arabidopsis / genetics
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Arabidopsis / growth & development*
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Bacillus subtilis / chemistry*
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Capsicum / drug effects
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Capsicum / enzymology
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Capsicum / genetics
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Capsicum / growth & development
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Chromatography, Thin Layer
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Down-Regulation
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Enzyme Activation
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Enzyme Assays
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Enzyme Inhibitors / chemistry
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Enzyme Inhibitors / pharmacology
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Gene Expression Regulation, Plant*
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Genes, Plant
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Gibberellins / biosynthesis
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Glycosyltransferases / antagonists & inhibitors
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Glycosyltransferases / chemistry
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Glycosyltransferases / genetics
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Lolium / drug effects
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Lolium / enzymology
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Lolium / genetics
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Lolium / growth & development*
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Mixed Function Oxygenases / antagonists & inhibitors
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Mixed Function Oxygenases / biosynthesis
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Mixed Function Oxygenases / genetics
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Phenylpropionates / chemistry
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Phenylpropionates / pharmacology
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Pheromones / chemistry
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Pheromones / pharmacology*
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Plant Proteins / antagonists & inhibitors
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Plant Proteins / chemistry
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Plant Proteins / genetics
Substances
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Enzyme Inhibitors
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Gibberellins
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Phenylpropionates
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Pheromones
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Plant Proteins
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3-phenylpropionic acid
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Mixed Function Oxygenases
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gibberellin 3beta-hydroxylase
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Glycosyltransferases
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xyloglucan endotransglycosylase