16 matches found in 9 documents. Search time: 0.093 seconds. |
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Score: 7.00 | Title: A novel cytochrome P450 is implicated in brassinosteroid biosynthesis via the characterization of a rice dwarf mutant , dwarf11 , with reduced seed length .
| Author: Tanabe S Ashikari M Fujioka S Takatsuto S Yoshida S Yano M Yoshimura A Kitano H Matsuoka M Fujisawa Y Kato H Iwasaki Y | Journal: Plant Cell Citation: V : 17 ( 3 ) P : 776-90 Year: 2005 | Literature: oryza Field: abstract Doc ID: pub15705958 Accession (PMID): 15705958 | Abstract: We have characterized a rice ( Oryza sativa ) dwarf mutant , dwarf11 ( d11 ) , that bears seeds of reduced length .
To understand the mechanism by which seed length is regulated , the D11 gene was isolated by a map-based cloning method .
The gene was found to encode a novel cytochrome P450 ( CYP724B1 ) , which showed homology to enzymes involved in brassinosteroid ( BR ) biosynthesis .
The dwarf phenotype of d11 mutants was restored by the application of the brassinolide ( BL ) .
Compared with wild-type plants , the aberrant D11 mRNA accumulated at higher levels in d11 mutants and was dramatically reduced by treatment with BL , implying that the gene is feedback-regulated by BL .
Precise determination of the defective step ( s ) in BR synthesis in d11 mutants proved intractable because of it issue specificity and the complex control of BR accumulation in plants .
However , 6-deoxotyphasterol ( 6-DeoxoTY ) and typhasterol ( TY ) , but not any upstream intermediates before these compounds , effectively restored BR response in d11 mutants in a lamina joint bending assay .
Multiple lines of evidence together suggest that the D11/CYP724B1 gene plays a role in BR synthesis and may be involved in the supply of 6-DeoxoTY and TY in the BR biosynthesis network in rice . | Matching Sentences: [ Sen. 5, subscore: 2.00 ]: Compared with wild-type plants , the aberrant D11 mRNA accumulated at higher levels in d11 mutants and was dramatically reduced by treatment with BL , implying that the gene is feedback-regulated by BL . [ Sen. 1, subscore: 1.00 ]: We have characterized a rice ( Oryza sativa ) dwarf mutant , dwarf11 ( d11 ) , that bears seeds of reduced length . [ Sen. 2, subscore: 1.00 ]: To understand the mechanism by which seed length is regulated , the D11 gene was isolated by a map-based cloning method . [ Sen. 4, subscore: 1.00 ]: The dwarf phenotype of d11 mutants was restored by the application of the brassinolide ( BL ) . [ Sen. 6, subscore: 1.00 ]: Precise determination of the defective step ( s ) in BR synthesis in d11 mutants proved intractable because of it issue specificity and the complex control of BR accumulation in plants . [ Sen. 7, subscore: 1.00 ]: However , 6-deoxotyphasterol ( 6-DeoxoTY ) and typhasterol ( TY ) , but not any upstream intermediates before these compounds , effectively restored BR response in d11 mutants in a lamina joint bending assay .
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Score: 3.00 | Title: Categories and inheritance of resistance to Nilaparvata lugens ( Hemiptera : Delphacidae ) in mutants of indica rice IR64 .
| Author: Sangha JS Chen YH Palchamy K Jahn GC Maheswaran M Adalla CB Leung H | Journal: J Econ Entomol Citation: V : 101 P : 575-83 Year: 2008 | Literature: oryza Field: abstract Doc ID: pub18459427 Accession (PMID): 18459427 | Abstract: Varietal mutants can be useful for developing durable resistance , understanding categories of resistance , and identifying candidate genes involved in defense responses .
We used mutants of rice IR64 to isolate new sources of resistance to the planthopper Nilaparvata lugens ( Stal ) ( Hemiptera : Delphacidae ) .
We compared two mutants that showed a gain and loss of resistance to N lugens , to determine the categories of resistance to this pest Under choice tests , female planthoppers avoided settling and laid fewer eggs on the resistant mutant D518 than on the susceptible mutant D1131 , susceptible check TN1 , and wild-type IR64 , indicating that antixenosis was the resistance category .
Similarly , under no-choice conditions , planthoppers laid 29% fewer eggs in D518 than in IR64 , but they oviposited more in D1131 and TN1 .
Honeydew excretion was greater on D1131 seedlings but slightly lower on D518 than on IR64 .
Nymphal survival and adult female weight did not differ among rice cultivars .
D518 showed higher tolerance of N lugens infestations than IR64 .
Genetic analysis of the F1 , F2 , and F3 populations derived from D518 x IR64 revealed that resistance in D518 is dominant and controlled by a single gene .
Despite the variation in resistance to N lugens , both mutants and IR64 performed similarly in the field .
The mutant D518 is a new source of durable resistance to N lugens , mainly due to enhanced antixenosis to female hoppers for settling and oviposition .
| Matching Sentences: [ Sen. 3, subscore: 1.00 ]: We compared two mutants that showed a gain and loss of resistance to N lugens , to determine the categories of resistance to this pest Under choice tests , female planthoppers avoided settling and laid fewer eggs on the resistant mutant D518 than on the susceptible mutant D1131 , susceptible check TN1 , and wild-type IR64 , indicating that antixenosis was the resistance category . [ Sen. 4, subscore: 1.00 ]: Similarly , under no-choice conditions , planthoppers laid 29% fewer eggs in D518 than in IR64 , but they oviposited more in D1131 and TN1 . [ Sen. 5, subscore: 1.00 ]: Honeydew excretion was greater on D1131 seedlings but slightly lower on D518 than on IR64 .
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Score: 1.00 | Title: Isoform-specific effects of charged residues at borders of the M1-M2 loop of the Na , K-ATPase alpha subunit .
| Author: Coppi MV Compton LA Guidotti G | Journal: Biochemistry Citation: V : 38 ( 8 ) P : 2494-505 Year: 1999 | Literature: oryza Field: abstract Doc ID: pub10029544 Accession (PMID): 10029544 | Abstract: The Na , K-ATPase is specifically inhibited by the cardiac glycoside , ouabain .
Via a largely undefined mechanism , the ouabain affinity of the Na , K-ATPase can be manipulated by mutating the residues at the borders of the first extracellular ( M1-M2 ) loop of the alpha subunit [ Price , E M , Rice , D A , and Lingrel , J B ( 1990 ) J Biol . Chem . 265 , 6638-6641 ] .
To address this issue , we compared the effects of two combinations of charged residues at the M1-M2 loop border , R113 , D124 and D113 , R124 ( numbered according to the rat alpha1 subunit ) , on the ouabain sensitivity of the alpha1 and alpha2 isoforms .
We report that ouabain sensitivity is dependent not only upon the identity of the residues at the M1-M2 loop border but also upon the context into which they are introduced .
Furthermore , at low concentrations of ATP , the identity of the residues at the M1-M2 loop border affects the regulation of ATP hydrolysis by potassium in an isoform-specific manner .
Analysis of chimeric alpha subunits reveals that the effects of potassium are determined primarily by the interaction of the N-terminus and M1-M2 loop with the C-terminal third of the alpha subunit .
M1-M2 loop border residues may , therefore , influence ouabain sensitivity indirectly by altering the stability or structure of the intermediate of the Na , K-ATPase catalytic cycle which is competent to bind ouabain .
| Matching Sentences: [ Sen. 3, subscore: 1.00 ]: To address this issue , we compared the effects of two combinations of charged residues at the M1-M2 loop border , R113 , D124 and D113 , R124 ( numbered according to the rat alpha1 subunit ) , on the ouabain sensitivity of the alpha1 and alpha2 isoforms .
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Score: 1.00 | 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 Year: 2005 | 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 .
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Score: 1.00 | 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 Year: 2009 | 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 .
| Matching Sentences: [ Sen. 4, subscore: 1.00 ]: The other BR-biosynthetic mutants , brd2 , osdwarf4 and d11 , which are defective in C-22-hydroxylated BRs , showed less or no response to auxin .
| Supplemental links/files: reference in endnote online text related articles pubmed citation | |