Score: 3.00 |
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| Title: Initiation of shoot apical meristem in rice : characterization of four SHOOTLESS genes .
| | Author: Satoh N Hong SK Nishimura A Matsuoka M Kitano H Nagato Y | | Journal: Development Year: 1999 Type: ARTICLE | | Literature: oryza Field: abstract Doc ID: pub10409508 Accession (PMID): 10409508 | | Abstract: The regulatory mechanism of shoot apical meristem ( SAM ) initiation is an important subject in developmental plant biology .
We characterized nine recessive mutations derived from four independent loci ( SHL1-SHL4 ) causing the deletion of the SAM .
Radicles were produced in these mutant embryos .
Concomitant with the loss of SAM , two embryo-specific organs , coleoptile and epiblast , were lost , but the scutellum was formed normally .
Therefore , differentiation of radicle and scutellum is regulated independently of SAM , but that of coleoptile and epiblast may depend on SAM .
Regeneration experiments using adventitious shoots from the scutellum-derived calli showed that no adventitious shoots were regenerated in any shl mutant .
However , small adventitious leaves were observed in both mutant and wild-type calli , but they soon became necrotic and showed no extensive growth .
Thus , leaf primordia can initiate in the absence of SAM , but their extensive growth requires the SAM .
An in situ hybridization experiment using a rice homeobox gene , OSH1 , as a probe revealed that shl1 and shl2 modified the expression domain of OSH1 , but normal expression of OSH1 was observed in shl3 and shl4 embryos .
Accordingly , SHL1 and SHL2 function upstream of OSH1 , and SHL3 and SHL4 downstream or independently of OSH1 .
These shl mutants are useful for elucidating the genetic program driving SAM initiation and for unraveling the interrelationships among various organs in grass embryos . | Matching Sentences:
[ Sen. 2, subscore: 1.00 ]: We characterized nine recessive mutations derived from four independent loci ( SHL1-SHL4 ) causing the deletion of the SAM .
[ Sen. 9, subscore: 1.00 ]: An in situ hybridization experiment using a rice homeobox gene , OSH1 , as a probe revealed that shl1 and shl2 modified the expression domain of OSH1 , but normal expression of OSH1 was observed in shl3 and shl4 embryos .
[ Sen. 10, subscore: 1.00 ]: Accordingly , SHL1 and SHL2 function upstream of OSH1 , and SHL3 and SHL4 downstream or independently of OSH1 .
| | Supplemental links/files: reference in endnote online text related articles pubmed citation | |
Score: 5.00 |
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| Title: The SHOOTLESS2 and SHOOTLESS1 genes are involved in both initiation and maintenance of the shoot apical meristem through regulating the number of indeterminate cells .
| | Author: Satoh N Itoh J Nagato Y | | Journal: Genetics Year: 2003 Type: ARTICLE | | Literature: oryza Field: abstract Doc ID: pub12750344 Accession (PMID): 12750344 | | Abstract: To characterize the SHL2 and SHL1 genes in detail , we analyzed three strains carrying weak alleles of SHL2 , shl2-6 , shl2-7 , and shl2-8 , and one weak allele of SHL1 , shl1-3 .
In contrast to strong alleles , which result in lack of shoot meristem , strains bearing these weak alleles formed shoot meristem frequently during embryogenesis .
In shl2-6 and shl2-7 mutants , the meristem was lost during seed development .
Only the shl2-8 mutant could survive after germination , but it showed abnormal initiation pattern and morphology of leaves .
In strains bearing the weak alleles , the shoot meristem was composed of a small number of indeterminate cells and ultimately converted into leaf primordium .
The shl1-3 mutant showed phenotypes similar to those of shl2-8 .
Thus SHL2 and SHL1 are required for both initiation and maintenance of shoot meristem .
In shl2 mutants , there was a positive correlation between the size of the expression domain of OSH1 representing the number of indeterminate cells , the frequency of shoot meristem initiation , and the duration of meristem survival Thus the shoot meristem will not initiate in an "all-or-nothing" fashion , but is formed in various degrees depending on the strength of the alleles .
Double-mutant analyses indicate that SHL2 functions upstream of SHO to establish proper organization of the shoot meristem . | Matching Sentences:
[ Sen. 1, subscore: 3.00 ]: To characterize the SHL2 and SHL1 genes in detail , we analyzed three strains carrying weak alleles of SHL2 , shl2-6 , shl2-7 , and shl2-8 , and one weak allele of SHL1 , shl1-3 .
[ Sen. 6, subscore: 1.00 ]: The shl1-3 mutant showed phenotypes similar to those of shl2-8 .
[ Sen. 7, subscore: 1.00 ]: Thus SHL2 and SHL1 are required for both initiation and maintenance of shoot meristem .
| | Supplemental links/files: reference in endnote online text related articles pubmed citation | |
