Score: 6.00 | Title: Isolation and characterization of a rice WUSCHEL-type homeobox gene that is specifically expressed in the central cells of a quiescent center in the root apical meristem .
| Journal: Plant J Citation: V : 35 ( 4 ) P : 429-41 Year: 2003 Type: ARTICLE | Literature: oryza Field: abstract Doc ID: pub12904206 | Abstract: The Arabidopsis WUSCHEL ( WUS ) protein , which plays an important role in the specification of the stem cells in the shoot apical meristem ( SAM ) , contains an atypical homeodomain ( HD ) with extra residues in its loop and turn regions .
We speculated that a WUS-type atypical HD protein might also be involved in the specification and maintenance of the root apical meristem ( RAM ) stem cells of rice .
To investigate this possibility , we isolated and characterized a rice WUS-type homeobox gene designated quiescent-center-specific homeobox ( QHB ) gene .
Using transformants carrying the QHB promoter-GUS and in situ hybridization , we found that QHB was specifically expressed in the central cells of a quiescent center ( QC ) of the root .
During embryogenesis and crown root formation , QHB expression was observed prior to the morphological differentiation of the root .
However , we detected different QHB expression patterns in the process of the RAM development , specifically between radicle and crown root formation , suggesting that the cell-fate determination of the QC may be controlled by different mechanisms .
We also produced transformants that overexpress QHB or Arabidopsis WUS .
These transformants did not form crown roots , but developed multiple shoots from ectopic SAMs with malformed leaves .
On the basis of these observations , we propose that the WUS-type homeobox gene is involved in the specification and maintenance of the stem cells ( QC cells ) in the RAM , by a mechanism similar to that for WUS in the SAM . | Matching Sentences: [ Sen. 4, subscore: 2.00 ]: Using transformants carrying the QHB promoter-GUS and in situ hybridization , we found that QHB was specifically expressed in the central cells of a quiescent center ( QC ) of the root . [ Sen. 3, subscore: 1.00 ]: To investigate this possibility , we isolated and characterized a rice WUS-type homeobox gene designated quiescent-center-specific homeobox ( QHB ) gene . [ Sen. 5, subscore: 1.00 ]: During embryogenesis and crown root formation , QHB expression was observed prior to the morphological differentiation of the root . [ Sen. 6, subscore: 1.00 ]: However , we detected different QHB expression patterns in the process of the RAM development , specifically between radicle and crown root formation , suggesting that the cell-fate determination of the QC may be controlled by different mechanisms . [ Sen. 7, subscore: 1.00 ]: We also produced transformants that overexpress QHB or Arabidopsis WUS .
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Score: 1.00 | Title: OsIAA23-mediated auxin signaling defines postembryonic maintenance of QC in rice .
| Journal: Plant J Citation: V : 68 P : 433-42 Year: 2011 Type: In-Process | Literature: oryza Field: abstract Doc ID: pub21736653 | Abstract: Although the quiescent center ( QC ) is crucial to root development , the molecular mechanisms that regulate its postembryonic maintenance remain obscure .
In this study , a semi-dominant mutant that exhibits pleiotropic defects in root it issues , which includes the root cap , lateral and crown roots , was isolated .
The mutant is characterized by a loss of QC identity during postembryonic development , and the displayed defects result from a stabilizing mutation in domain II of OsIAA23 ( Os06g39590 ) .
Expression of OsIAA23 is specific to the QC of the root tip during the development of primary , lateral and crown roots .
Consistent with OsIAA23 expression in the QC , the auxin signaling marked by DR5p : : GUS ( ss-glucuronidase ) was absent in the QC region of Osiaa23 .
Transgenic rice plants harboring Osiaa23 under the control of the QHB promoter mimic partially the defects of Osiaa23 .
These results indicate that the maintenance of the QC is dependent on OsIAA23-mediated auxin signaling in the QC .
These findings provide insight into Aux/IAA-based auxin signaling during postembryonic maintenance of the QC in plants .
| Matching Sentences: [ Sen. 6, subscore: 1.00 ]: Transgenic rice plants harboring Osiaa23 under the control of the QHB promoter mimic partially the defects of Osiaa23 .
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