| 21 matches found in 10 documents. Search time: 0.014 seconds. |
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| Title: Isolation and characterization of a rice dwarf mutant with a defect in brassinosteroid biosynthesis .
| | Author: Mori M Nomura T Ooka H Ishizaka M Yokota T Sugimoto K Okabe K Kajiwara H Satoh K Yamamoto K Hirochika H Kikuchi S | | Journal: Plant Physiol .
Citation: V : 130 ( 3 ) P : 1152-61 Type: ARTICLE | | Literature: oryza Field: abstract Doc ID: pub12427982 Accession (PMID): 12427982 | | Abstract: We have isolated a new recessive dwarf mutant of rice ( Oryza sativa L cv Nipponbare ) .
Under normal growth conditions , the mutant has very short leaf sheaths ; has short , curled , and frizzled leaf blades ; has few tillers ; and is sterile .
Longitudinal sections of the leaf sheaths revealed that the cell length along the longitudinal axis is reduced , which explains the short leaf sheaths .
Transverse sections of the leaf blades revealed enlargement of the motor cells along the dorsal-ventral axis , which explains the curled and frizzled leaf blades .
In addition , the number of crown roots was smaller and the growth of branch roots was weaker than those in the wild-type plant .
Because exogenously supplied brassinolide considerably restored the normal phenotypes , we designated the mutant brassinosteroid-dependent 1 ( brd1 ) .
Further , under darkness , brd1 showed constitutive photomorphogenesis .
Quantitative analyses of endogenous sterols and brassinosteroids ( BRs ) indicated that BR-6-oxidase , a BR biosynthesis enzyme , would be defective .
In fact , a 0 . 2-kb deletion was detected in the genomic region of OsBR6ox ( a rice BR-6-oxidase gene ) in the brd1 mutant .
These results indicate that BRs are involved in many morphological and physiological processes in rice , including the elongation and unrolling of leaves , development of tillers , skotomorphogenesis , root differentiation , and reproductive growth , and that the defect of BR-6-oxidase caused the brd1 phenotype . | Matching Sentences:
[ Sen. 6, subscore: 1.00 ]: Because exogenously supplied brassinolide considerably restored the normal phenotypes , we designated the mutant brassinosteroid-dependent 1 ( brd1 ) .
[ Sen. 7, subscore: 1.00 ]: Further , under darkness , brd1 showed constitutive photomorphogenesis .
[ Sen. 9, subscore: 1.00 ]: In fact , a 0 . 2-kb deletion was detected in the genomic region of OsBR6ox ( a rice BR-6-oxidase gene ) in the brd1 mutant .
[ Sen. 10, subscore: 1.00 ]: These results indicate that BRs are involved in many morphological and physiological processes in rice , including the elongation and unrolling of leaves , development of tillers , skotomorphogenesis , root differentiation , and reproductive growth , and that the defect of BR-6-oxidase caused the brd1 phenotype .
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Score: 4.00 |
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| Title: Loss-of-function of a rice brassinosteroid biosynthetic enzyme , C-6 oxidase , prevents the organized arrangement and polar elongation of cells in the leaves and stem .
| | Author: Hong Z Ueguchi-Tanaka M Shimizu-Sato S Inukai Y Fujioka S Shimada Y Takatsuto S Agetsuma M Yoshida S Watanabe Y Uozu S Kitano H Ashikari M Matsuoka M | | Journal: Plant J Citation: V : 32 ( 4 ) P : 495-508 Type: ARTICLE | | Literature: oryza Field: abstract Doc ID: pub12445121 Accession (PMID): 12445121 | | Abstract: Molecular genetic and physiological studies on brassinosteroid ( BR ) -related mutants of dicot plants have revealed that BRs play important roles in normal plant growth and development .
However , little is known about the function of BR in monocots ( grasses ) , except for the phenotypic analysis of a rice mutant partially insensitive to BR signaling .
To investigate the function of BR in monocots , we identified and characterized BR-deficient mutants of rice , BR-deficient dwarf1 ( brd1 ) .
The brd1 mutants showed a range of abnormalities in organ development and growth , the most striking of which were defects in the elongation of the stem and leaves .
Light microscopic observations revealed that this abnormality was primarily owing to a failure in the organization and polar elongation of the leaf and stem cells .
The accumulation profile of BR compounds in the brd1 mutants suggested that these plants may be deficient in the activity of BR C-6 oxidase .
Therefore , we cloned a rice gene , OsDWARF , which has a high sequence similarity to the tomato C-6 oxidase gene , DWARF .
Introduction of the wild-type OsDWARF gene into brd1 rescued the abnormal phenotype of the mutants .
The OsDWARF gene was expressed at a low level in all of the examined it issues , with preferential expression in the leaf sheath , and the expression was negatively regulated by brassinolide treatment .
On the basis of these findings , we discuss the biological function of BRs in rice plants . | Matching Sentences:
[ Sen. 3, subscore: 1.00 ]: To investigate the function of BR in monocots , we identified and characterized BR-deficient mutants of rice , BR-deficient dwarf1 ( brd1 ) .
[ Sen. 4, subscore: 1.00 ]: The brd1 mutants showed a range of abnormalities in organ development and growth , the most striking of which were defects in the elongation of the stem and leaves .
[ Sen. 6, subscore: 1.00 ]: The accumulation profile of BR compounds in the brd1 mutants suggested that these plants may be deficient in the activity of BR C-6 oxidase .
[ Sen. 8, subscore: 1.00 ]: Introduction of the wild-type OsDWARF gene into brd1 rescued the abnormal phenotype of the mutants .
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Score: 2.00 |
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| Title: The Rice brassinosteroid-deficient dwarf2 mutant , defective in the rice homolog of Arabidopsis DIMINUTO/DWARF1 , is rescued by the endogenously accumulated alternative bioactive brassinosteroid , dolichosterone .
| | Author: Hong Z Ueguchi-Tanaka M Fujioka S Takatsuto S Yoshida S Hasegawa Y Ashikari M Kitano H Matsuoka M | | Journal: Plant Cell Citation: V : 17 ( 8 ) P : 2243-54 Type: ARTICLE | | Literature: oryza Field: abstract Doc ID: pub15994910 Accession (PMID): 15994910 | | Abstract: We have identified a rice ( Oryza sativa ) brassinosteroid ( BR ) -deficient mutant , BR-deficient dwarf2 ( brd2 ) .
The brd2 locus contains a single base deletion in the coding region of Dim/dwf1 , a homolog of Arabidopsis thaliana DIMINUTO/DWARF1 ( DIM/DWF1 ) .
Introduction of the wild-type Dim/dwf1 gene into brd2 restored the normal phenotype .
Overproduction and repression of Dim/dwf1 resulted in contrasting phenotypes , with repressors mimicking the brd2 phenotype and overproducers having large stature with increased numbers of flowers and seeds .
Although brd2 contains low levels of common 6-oxo-type BRs , the severity of the brd2 phenotype is much milder than brd1 mutants and most similar to d2 and d11 , which show a semidwarf phenotype at the young seedling stage .
Quantitative analysis suggested that in brd2 , the 24-methylene BR biosynthesis pathway is activated and the uncommon BR , dolichosterone ( DS ) , is produced .
DS enhances the rice lamina joint bending angle , rescues the brd1 dwarf phenotype , and inhibits root elongation , indicating that DS is a bioactive BR in rice .
Based on these observations , we discuss an alternative BR biosynthetic pathway that produces DS when Dim/dwf1 is defective . | Matching Sentences:
[ Sen. 5, subscore: 1.00 ]: Although brd2 contains low levels of common 6-oxo-type BRs , the severity of the brd2 phenotype is much milder than brd1 mutants and most similar to d2 and d11 , which show a semidwarf phenotype at the young seedling stage .
[ Sen. 7, subscore: 1.00 ]: DS enhances the rice lamina joint bending angle , rescues the brd1 dwarf phenotype , and inhibits root elongation , indicating that DS is a bioactive BR in rice .
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Score: 1.00 |
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| Title: OsBLE3 , a brassinolide-enhanced gene , is involved in the growth of rice .
| | Author: Yang G Nakamura H Ichikawa H Kitano H Komatsu S | | Journal: Phytochemistry Citation: V : 67 ( 14 ) P : 1442-54 Type: ARTICLE | | Literature: oryza Field: abstract Doc ID: pub16808934 Accession (PMID): 16808934 | | Abstract: Brassinosteroids ( BRs ) are a group of plant hormones involved in a wide range of plant growth and developmental processes .
To investigate the mechanism of BR action in monocots , a brassinolide ( BL ) upregulated gene designated OsBLE3 was identified , cloned and characterized in rice .
It was mainly expressed in roots and leaf sheaths with levels of expression directly dependent on the dose of BL .
In situ hybridization detected OsBLE3 mRNA in the shoot apical meristem , organ primordia and vascular it issue .
Furthermore , its expression was enhanced by co-treatment with BL and low concentrations of IAA .
These results , and the existence of auxin response elements in the 5-flanking region of the OsBLE3 gene , indicate that OsBLE3 expression is under control of both BR and auxin .
The GUS reporter gene driven by a 2277 bp OsBLE3 putative promoter was mainly expressed in vascular it issues , branch root primordia and was responsive to exogenous BL treatment .
OsBLE3 transcript levels were greatly reduced in brd1 plants , a BL deficient mutant , compared to the wild type control .
In OsBRI1 antisense transgenic rice and OsBLE3 , the BR-insensitive mutant expression of OsBLE3 in response to exogenous BL treatment was significantly lower compared to that in control plants transformed with a vacant vector .
Reduced OsBLE3 expression and growth retardation was also observed in OsBLE3 antisense transgenic rice plants .
Internode cell length of the OsBLE3 antisense transgenic lines was about 70% of that in the vacant vector transformed control lines .
These results suggest that OsBLE3 is involved in cell elongation in rice through dual regulation by BL and IAA . | Matching Sentences:
[ Sen. 8, subscore: 1.00 ]: OsBLE3 transcript levels were greatly reduced in brd1 plants , a BL deficient mutant , compared to the wild type control .
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Score: 1.00 |
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| Title: Involvement of C-22-hydroxylated brassinosteroids in auxin-induced lamina joint bending in rice .
| | Author: Nakamura A Fujioka S Takatsuto S Tsujimoto M Kitano H Yoshida S Asami T Nakano T | | Journal: Plant Cell Physiol Citation: V : 50 P : 1627-35 Type: MEDLINE | | Literature: oryza Field: abstract Doc ID: pub19605414 Accession (PMID): 19605414 | | Abstract: The rice lamina joint is ideal material for investigating the activity of brassinosteroids ( BRs ) and auxin because of its high sensitivity to these compounds .
Using a series of rice BR biosynthetic and receptor mutants , we conducted lamina joint tests to elucidate the mechanism of cross-talk between BR and auxin signaling in lamina joint bending .
In BR biosynthetic mutants d2 and brd1 , which are defective in C-23 hydroxylase and C-6 oxidase , respectively , the lamina joint response to auxin was significantly higher than that of wild-type plants .
The other BR-biosynthetic mutants , brd2 , osdwarf4 and d11 , which are defective in C-22-hydroxylated BRs , showed less or no response to auxin .
These results suggest that C-22-hydroxylated BRs are involved in auxin-induced lamina joint bending .
The results were supported by the observation that inhibition of the hyper-response to auxin in d2 was reduced by treatment with brassinazole , which inhibits the function of DWARF4 , the C-22 hydroxylase .
In d61 , which is defective in OsBRI1 , a possible BR receptor in rice , the bending angle of the lamina joint in response to auxin and C-22-hydroxylated 6-deoxoBRs was nearly the same as that in wild-type plants .
This implies that C-22-hydroxylated BRs function in auxin signaling independently of OsBRI1 .
From these observations , we propose that C-22-hydroxylated BRs participate in auxin signaling via a novel OsBRI1-independent signaling pathway .
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[ Sen. 3, subscore: 1.00 ]: In BR biosynthetic mutants d2 and brd1 , which are defective in C-23 hydroxylase and C-6 oxidase , respectively , the lamina joint response to auxin was significantly higher than that of wild-type plants .
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