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Query: UMLS:C0277787 (stigma)
 13,352 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Self-incompatible Brassica napus ssp. oleifera lines were generated by introgressing the S-locus from the self-incompatible B. napus ssp. rapifera Z line into the self-compatible cultivars, Topas and Regent, resulting in T2 and R2, respectively. Screening of a cDNA library made from R2 stigma RNA produced several candidate SLG (S-locus glycoprotein) cDNAs. One of the cDNAs, A14, was found to be represented in only the R2, T2 and Z lines. In addition, the corresponding A14 gene was demonstrated to segregate with the T2 self-incompatibility phenotype in an F2 population derived from a cross between T2 and Topas, and to exhibit high mRNA levels in the stigmas prior to anthesis. Sequence analysis of the A14 cDNA revealed close homology to B. oleracea SLG alleles associated with a Class I high activity self-incompatibility phenotype.
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PMID:Identification of an S-locus glycoprotein allele introgressed from B. napus ssp. rapifera to B. napus ssp. oleifera. 130 44

The sequence is reported of a cDNA molecule homologous to an mRNA from stigma tissue of Brassica oleracea plants homozygous for the S5 self-incompatibility allele. This cDNA is closely related to a previously published sequence designated SLR2, which was obtained from the same stigma cDNA library and is also related to the SLR1 gene, a cDNA for which has also been obtained from this library. Various B. oleracea lines differing in S alleles and of different varieties have been screened for the presence of particular S gene family sequences using a method involving hybridization of sequence-specific oligonucleotide probes to PCR products. The results indicate that a gene homologous to the sequence presented here is absent from a line lacking the S5 allele, though present in other lines containing the S5 allele, regardless of their genetic background. This finding suggests that the sequence represents a transcript of the SLG (S locus glycoprotein) gene. A similar approach has confirmed that a cDNA derived from a Brassica line containing the S29 allele is also S allele-specific. The predicted amino acid sequences derived from a number of S gene family sequences are compared using numerical methods and possible evolutionary relationships between them are discussed.
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PMID:An S5 self-incompatibility allele-specific cDNA sequence from Brassica oleracea shows high homology to the SLR2 gene. 155 30

Self-incompatibility in Brassica oleracea is controlled by a single genetic locus (the S locus) with nearly 50 different alleles. In this paper, we report the characterization of the S2 allele, a pollen recessive self-incompatibility allele that exhibits weak DNA homology to the other previously sequenced S locus glycoprotein genes (SLG-6, -13, -14, -22 from alleles S6, S13, S14 and S22, respectively). Stigma cDNA clones with sequence homology to SLG-13 were isolated from two different S2 homozygous strains belonging to two different B. oleracea cultivars, var. alboglabra (Chinese kale) and var. italica (broccoli). The two S2 cDNA sequences are 90% homologous to each other, but only 70% homologous to SLG-13. Using the Chinese kale S2 genetic background, we demonstrate that the isolated alboglabra cDNA sequence is a transcript from a gene, designated SLG-2A that resides at the S locus, and propose that it is a putative determinant of S2 allelic specificity. Among the estimated 10-15 genomic copies of SLG-related genes detected in the S2 genome, we cloned and characterized the SLG-2A gene and another closely related and genetically linked gene copy, SLG-2B. A complete open reading frame that is 94% homologous to SLG-2A is located within SLG-2B. The existence of this intact duplicated S gene raises the possibility that SLG-2B may also be involved in the functioning of self-incompatibility in Brassica oleracea.
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PMID:A new class of S sequences defined by a pollen recessive self-incompatibility allele of Brassica oleracea. 198 Mar 34

The S-locus-specific glycoprotein of Brassica and the gene encoding it (the SLG gene) are thought to be involved in determining self-incompatibility phenotype in this genus. It has been shown that the Brassica genome contains multiple SLG-related sequences. We report here the cloning and characterization of a Brassica oleracea gene, SLR1, which corresponds to one of these SLG-related sequences. Like the SLG gene, SLR1 is developmentally regulated. It is maximally expressed in the papillar cells of the stigma at the same stage of flower development as the onset of the incompatibility response. Unlike SLG, the SLR1 genes isolated from different S-allele homozygotes are highly conserved, and this gene, which appears to be ubiquitous in crucifers, is expressed in self-compatible strains as well as self-incompatible strains. Most importantly, we show that the SLR1 gene is not linked to the S-locus and therefore cannot be a determinant of S-allele specificity in Brassica.
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PMID:A highly conserved Brassica gene with homology to the S-locus-specific glycoprotein structural gene. 253 45

Self-incompatibility in Brassica is controlled by the S locus which contains at least two genes. SLG encodes a secreted S locus glycoprotein whilst SRK encodes a putative S locus receptor kinase which consists of three domains: an extracellular domain sharing extensive sequence identity with SLG, transmembrane region, and a cytoplasmic domain exhibiting a serine/threonine protein kinase activity. Here, the existence of truncated forms of the SRK protein corresponding to the extracellular domain of the putative receptor is reported. These proteins were detected by an antibody which recognizes the N-terminus of SRK3 and, in an F2 progeny segregating for the S3 haplotype, were only expressed in plants possessing the S3 haplotype. The truncated SRK proteins were expressed specifically in stigmas but, unlike the membrane-spanning SRK3 protein, were soluble and occurred as four different glycoforms sharing the same amino acid backbone as shown by deglycosylation experiments. Several SRK3 transcripts that may code for these truncated SRK3 proteins have been identified by RACE PCR, stigma cDNA library screening and RNA blot analysis. These transcripts are apparently generated by a combination of alternative splicing and the use of alternative polyadenylation signals. The existence of truncated forms of the S locus receptor kinase highlights some similarities between plant and animal receptor kinases. In animals, soluble extracellular domains of receptors have been described and, in some cases, have been shown to play a role in the modulation of signal transduction. By analogy, the soluble, truncated SRK proteins may play a similar role in the self-incompatibility response.
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PMID:The S locus receptor kinase gene encodes a soluble glycoprotein corresponding to the SKR extracellular domain in Brassica oleracea. 858 Sep 56

The S3 allele of the S gene has been cloned from Papaver rhoeas cv. Shirley. The sequence predicts a hydrophilic protein of 14.0 kDa, showing 55.8% identity with the previously cloned S1 allele, preceded by an 18 amino acid signal sequence. Expression of the S3 coding region in Escherichia coli produced a form of the protein, denoted S3e, which specifically inhibited S3 pollen in an in vitro bioassay. The recombinant protein was ca. 0.8 kDa larger than the native stigmatic form, indicating post-translational modifications in planta, as was previously suggested for the S1 protein. In contrast to other S proteins identified to date, S3 protein does not appear to be glycosylated. Of particular significance is the finding that despite exhibiting a high degree of sequence polymorphism, secondary structure predictions indicate that the S1 and S3 proteins may adopt a virtually identical conformation. Sequence analysis also indicates that the S1 and S3 proteins may adopt a virtually identical conformation. Sequence analysis also indicates that the P. rhoeas S alleles share some limited homology with the SLG and SRK genes from Brassica oleracea. Previously, cross-classification of different populations of P. rhoeas had revealed a number of functionally identical alleles. Probing of Western blots of stigma proteins from plants derived from a wild Spanish population which contained an allele functionally identical to the Shirley S3 allele with antiserum raised to S3e, revealed a protein (S3s) which was indistinguishable in pI and Mr from that in the Shirley population. A cDNA encoding S3s was isolated, nucleotide sequencing revealing a coding region with 99.4% homology with the Shirley-derived clone at the DNA level, and 100% homology at the amino acid level.
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PMID:Molecular analysis of two functional homologues of the S3 allele of the Papaver rhoeas self-incompatibility gene isolated from different populations. 863 56

The self-incompatibility (SI) response in Brassica involves recognition of self-pollen by the papillar cells of the stigma and is mediated by the products of genes localized at the S (self-incompatibility) locus. Two S locus genes, SRK and SLG, are thought to encode components of a receptor complex present in the female partner. The putative gene product of SLA, a third S locus-linked gene that is expressed specifically in anthers, is a candidate for the male component of the SI recognition system. The identification of a mutant SLA allele, interrupted by a large insert resembling a retrotransposon, in self-compatible Brassica napus initially suggested that SLA played an essential role in the SI response. In this study, we have characterized an SLA allele from a self-compatible B. oleracea var acephala line and show that it too is interrupted by a large insert. However, analysis of seven B. oleracea var botrytis lines exhibiting both self-compatible and self-incompatible phenotypes showed that these lines carry an S allele very similar or identical to that of the B. oleracea var acephala line and that the SLA gene is interrupted by an insert in all seven lines. The insertion of the putative retrotransposon was shown to interfere with gene expression, with no SLA transcripts being detected by RNA gel blot analysis in a self-incompatible B. oleracea var botrytis line carrying an interrupted SLA gene. These data indicate that a functional SLA gene is not required for the SI response in Brassica.
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PMID:A functional S locus anther gene is not required for the self-incompatibility response in Brassica oleracea. 940 Nov 28

The self-incompatible (SI) Brassica napus line W1, which carries the 910 S allele, was transformed with an inactive copy of the 910 S locus receptor kinase (SRK) gene. Two transformed lines were analyzed based on their heritable ability to set self-seed. The first line was virtually completely self-compatible (SC), and reciprocal pollinations with the original W1 line demonstrated that only the stigma side of the SI phenotype was altered. An analysis of the expression of endogenous SRK-910 demonstrated that the mechanism of transgene action is via gene suppression. Furthermore, the expression of the S locus glycoprotein gene present in the 910 allele (SLG-910), SLG-A10, which is derived from a nonfunctional S allele, and an S locus-related gene were also suppressed. When the transgene was crossed into another SI line carrying the A14 S allele, it was also capable of suppressing the expression of the endogenous genes and of making this line SC. The second transgenic line studied was only partly SC. In this case as well, only the stigma phenotype was affected, although no gene suppression was detected for endogenous SRK-910 or SLG-910. In this line, the expression of the transgene most likely was causing the change in phenotype, and no effect was observed when this transgene was crossed into the other SI line. Therefore, this work reinforces the hypothesis that the SRK gene is required, but only for the stigma side of the SI phenotype, and that a single transgene can alter the SI phenotype of more than one S allele.
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PMID:The self-incompatibility phenotype in brassica is altered by the transformation of a mutant S locus receptor kinase 949 Jul 44

The S-locus glycoprotein gene, SLG, which participates in the pollen-stigma interaction of self-incompatibility, and its unlinked homologue, SLR1, were analyzed in Raphanus sativus and three self-incompatible ornamental plants in the Brassicaceae. Among twenty-nine inbred lines of R. sativus, eighteen S haplotypes were identified on the basis of DNA polymorphisms detected by genomic Southern analysis using Brassica SLG probes. DNA fragments of SLG alleles specifically amplified from eight S haplotypes by PCR with class I SLG-specific primers showed different profiles following polyacrylamide gel electrophoresis, after digestion with a restriction endonuclease. The nucleotide sequences of the DNA fragments of these eight R. sativus SLG alleles were determined. Degrees of similarity of the nucleotide sequences to a Brassica SLG (S6SLG) ranged from 85.6% to 91.9%. Amino acid sequences deduced from these had the twelve conserved cysteine residues and the three hypervariable regions characteristic of Brassica SLGs. Phylogenetic analysis of the SLG sequences from Raphanus and Brassica revealed that the Raphanus SLGs did not form an independent cluster, but were dispersed in the tree, clustering together with Brassica SLGs. These results suggest that diversification of the SLG alleles of Raphanus and Brassica occurred before differentiation of these genera. Although SLR1 sequences from Orychophragmus violaceus were shown to be relatively closely related to Brassica and Raphanus SLR1 sequences, DNA fragments that are highly homologous to the Brassica SLG were not detected in this species. Two other ornamental plants in the Brassicaceae, which are related more distantly to Brassica than Orychophragmus, also lacked sequences highly homologous to Brassica SLG genes. The evolution of self-incompatibility in the Brassicaceae is discussed.
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PMID:Polymorphism of the S-locus glycoprotein gene (SLG) and the S-locus related gene (SLR1) in Raphanus sativus L. and self-incompatible ornamental plants in the Brassicaceae. 964 45

In Brassica, two self-incompatibility genes, encoding SLG (S locus glycoprotein) and SRK (S-receptor kinase), are located at the S locus and expressed in the stigma. Recent molecular analysis has revealed that the S locus is highly polymorphic and contains several genes, i.e., SLG, SRK, the as-yet-unidentified pollen S gene(s), and other linked genes. In the present study, we searched for expressed sequences in a 76-kb SLG/SRK region of the S(9) haplotype of Brassica campestris (syn. rapa) and identified 10 genes in addition to the four previously identified (SLG(9), SRK(9), SAE1, and SLL2) in this haplotype. This gene density (1 gene/5.4 kb) suggests that the S locus is embedded in a gene-rich region of the genome. The average G + C content in this region is 32.6%. An En/Spm-type transposon-like element was found downstream of SLG(9). Among the genes we identified that had not previously been found to be linked to the S locus were genes encoding a small cysteine-rich protein, a J-domain protein, and an antisilencing protein (ASF1) homologue. The small cysteine-rich protein was similar to a pollen coat protein, named PCP-A1, which had previously been shown to bind SLG.
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PMID:Genomic organization of the S locus: Identification and characterization of genes in SLG/SRK region of S(9) haplotype of Brassica campestris (syn. rapa). 1047 21


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