scholarly journals S-RNase proteins: functional studies of the 120kDa glycoprotein and SRNase oligomerization

2005 ◽  
Author(s):  
◽  
Charles Nathan Hancock
Keyword(s):  
Nicotiana Alata ◽  
Self Incompatibility ◽  
S Locus ◽  
Transmitting Tract ◽  
Functional Studies ◽  
S Haplotype ◽  
S Factor ◽  
Self Association ◽  
Incompatible Cross ◽  
F Box Protein

Flowering plants control fertilization through pollen-pistil interactions. Self-incompatibility (SI) is a well-studied pollen-pistil interaction that promotes cross-pollination. SI is controlled by a multi-haplotype locus called the S-locus. In Nicotiana alata, S-RNase is a product of the S-locus and regulates specificity in the pistil, while S-locus F-box protein (SLF) controls specificity in the pollen. The interaction between S-RNase and SLF determines whether the pollination is compatible or incompatible. In an incompatible cross, the ribonuclease activity of S-RNase inhibits pollen tube growth. Genetic experiments indicate that, in addition to S-RNase and SLF, non-S-factors are also required for SI. S-RNase binding proteins represent potential non-S-factors required for SI. Using affinity chromatography, we found that S-RNase selfassociates and three homologous stylar glycoproteins - the 120kDa glycoprotein (120K), N. alata pistil extensin-like protein III (NaPELP III), and N. alata transmitting tract specific glycoprotein (NaTTS) - bind directly to S-RNase. I studied the oligomerization of S-RNase in detail and found that self-association is dependent on S-haplotype and buffer conditions. I determined that the components of the S-RNase complex account for 30% of soluble pistil protein. 120K is the most likely candidate for a non-S-factor because it enters the cytoplasm of growing pollen tubes and shows polymorphism when SI and self-compatible Nicotiana species are compared. To test its role in SI, I suppressed 120K expression using RNAi. Suppressing 120K caused a breakdown of SI, confirming that it functions in SI.

scholarly journals Patterns of polymorphism at the self-incompatibility locus in 1,083 Arabidopsis thaliana genomes

2017 ◽  
Author(s):  
Takashi Tsuchimatsu ◽  
Pauline M. Goubet ◽  
Sophie Gallina ◽  
Anne-Catherine Holl ◽  
Isabelle Fobis-Loisy ◽  
...  
Keyword(s):  
Arabidopsis Thaliana ◽  
Glacial Refugia ◽  
The Self ◽  
Ice Age ◽  
Self Incompatibility ◽  
S Locus ◽  
Sequencing Data ◽  
Functional Studies ◽  
Large Deletions ◽  
Last Ice Age

AbstractAlthough the transition to selfing in the model plant Arabidopsis thaliana involved the loss of the self-incompatibility (SI) system, it clearly did not occur due to the fixation of a single inactivating mutation at the locus determining the specificities of SI (the S-locus). At least three groups of divergent haplotypes (haplogroups), corresponding to ancient functional S-alleles, have been maintained at this locus, and extensive functional studies have shown that all three carry distinct inactivating mutations. However, the historical process of loss of SI is not well understood, in particular its relation with the last glaciation. Here, we took advantage of recently published genomic re-sequencing data in 1,083 Arabidopsis thaliana accessions that we combined with BAC sequencing to obtain polymorphism information for the whole S-locus region at a species-wide scale. The accessions differed by several major rearrangements including large deletions and inter-haplogroup recombinations, forming a set of haplogroups that are widely distributed throughout the native range and largely overlap geographically. ‘Relict’ A. thaliana accessions that directly derive from glacial refugia are polymorphic at the S-locus, suggesting that the three haplogroups were already present when glacial refugia from the last Ice Age became isolated. Inter-haplogroup recombinant haplotypes were highly frequent, and detailed analysis of recombination breakpoints suggested multiple independent origins. These findings suggest that the complete loss of SI in A. thaliana involved independent self-compatible mutants that arose prior to the last Ice Age, and experienced further rearrangements during post-glacial colonization.

scholarly journals Cross-incompatibility and self-incompatibility: unrelated phenomena in wild and cultivated potatoes?

Botany ◽  
2018 ◽  
Vol 96 (1) ◽  
pp. 33-45 ◽  
Author(s):  
Juan Federico Maune ◽  
Elsa Lucila Camadro ◽  
Luis Ernesto Erazzú
Keyword(s):  
Germplasm Conservation ◽  
Solanum Chacoense ◽  
Molecular Evidence ◽  
Self Incompatibility ◽  
S Locus ◽  
S Haplotype ◽  
Family Level ◽  
Sib Families ◽  
Cultivated Potatoes ◽  
The Individual

Knowledge of internal hybridization barriers is relevant for germplasm conservation and utilization. The two pre-zygotic barriers are pollen–pistil self-incompatibility (SI) and cross-incompatibility (CI). To ascertain whether SI and CI were phenotypically related phenomena in potatoes, extensive intra- and interspecific, both intra- and interploidy breeding relationships were established, without previous assumptions on the compatibility behavior of the studied germplasm. Pollen–pistil relationships were analyzed at the individual genotype/accession/family level. In two seasons, 828 intra- and interspecific genotypic combinations were performed, using accessions of the wild potatoes Solanum chacoense Bitter (2n = 2x = 24), S. gourlayi Hawkes (2n = 2x = 24; 2n = 4x = 48), and S. spegazzinii Bitter (2n = 2x = 24), full-sibling (hereinafter “full-sib”) families (2n = 2x = 24) within/between the latter two diploids, and S. tuberosum L. (2n = 4x = 48) cultivars. Pollen–pistil incompatibility occurred in the upper first third of the style (I1/3) in all selfed diploids. In both the intra- and interspecific combinations, the most frequent relationship was compatibility, followed by I1/3, but incompatibility also occurred in the stigma and the style (middle third and bottom third). We observed segregation for these relationships in full-sib families, and unilateral and bilateral incompatibility in reciprocal crosses between functional SI genotypes. Cross-incompatibility in potatoes is, apparently, controlled by genes independent of the S-locus or its S-haplotype recognition region (although molecular evidence is needed to confirm it), with segregation even within accessions.

scholarly journals Intrahaplotype Polymorphism at the Brassica S Locus

Genetics ◽  
2001 ◽  
Vol 159 (2) ◽  
pp. 811-822
Author(s):  
Christine Miege ◽  
Véronique Ruffio-Châble ◽  
Mikkel H Schierup ◽  
Didier Cabrillac ◽  
Christian Dumas ◽  
...  
Keyword(s):  
Class Ii ◽  
The Self ◽  
Self Incompatibility ◽  
Receptor Kinase ◽  
S Locus ◽  
S Haplotype

Abstract The S locus receptor kinase and the S locus glycoproteins are encoded by genes located at the S locus, which controls the self-incompatibility response in Brassica. In class II self-incompatibility haplotypes, S locus glycoproteins can be encoded by two different genes, SLGA and SLGB. In this study, we analyzed the sequences of these genes in several independently isolated plants, all of which carry the same S haplotype (S2). Two groups of S2 haplotypes could be distinguished depending on whether SRK was associated with SLGA or SLGB. Surprisingly, SRK alleles from the two groups could be distinguished at the sequence level, suggesting that recombination rarely occurs between haplotypes of the two groups. An analysis of the distribution of polymorphisms along the S domain of SRK showed that hypervariable domains I and II tend to be conserved within haplotypes but to be highly variable between haplotypes. This is consistent with these domains playing a role in the determination of haplotype specificity.

scholarly journals A Molecular Description of Mutations Affecting the Pollen Component of the Nicotiana alata S locus

Genetics ◽  
1999 ◽  
Vol 152 (3) ◽  
pp. 1123-1135 ◽  
Author(s):  
J F Golz ◽  
V Su ◽  
A E Clarke ◽  
E Newbigin
Keyword(s):  
Extra Chromosome ◽  
Nicotiana Alata ◽  
Self Incompatibility ◽  
S Locus ◽  
Cytological Examination ◽  
Mutagenesis Screen ◽  
Genes Encoding ◽  
Additional Chromosome ◽  
S Allele ◽  
Molecular Description

Abstract Mutations affecting the self-incompatibility response of Nicotiana alata were generated by irradiation. Mutants in the M1 generation were selected on the basis of pollen tube growth through an otherwise incompatible pistil. Twelve of the 18 M1 plants obtained from the mutagenesis screen were self-compatible. Eleven self-compatible plants had mutations affecting only the pollen function of the S locus (pollen-part mutants). The remaining self-compatible plant had a mutation affecting only the style function of the S locus (style-part mutant). Cytological examination of the pollen-part mutant plants revealed that 8 had an extra chromosome (2n + 1) and 3 did not. The pollen-part mutation in 7 M1 plants was followed in a series of crosses. DNA blot analysis using probes for S-RNase genes (encoding the style function of the S locus) indicated that the pollen-part mutation was associated with an extra S allele in 4 M1 plants. In 3 of these plants, the extra S allele was located on the additional chromosome. There was no evidence of an extra S allele in the 3 remaining M1 plants. The breakdown of self-incompatibility in plants with an extra S allele is discussed with reference to current models of the molecular basis of self-incompatibility.

scholarly journals Characterization of a Common S Haplotype BnS-6 in the Self-Incompatibility of Brassica napus

Plants ◽  
2021 ◽  
Vol 10 (10) ◽  
pp. 2186
Author(s):  
Zhiquan Liu ◽  
Bing Li ◽  
Yong Yang ◽  
Changbin Gao ◽  
Bin Yi ◽  
...  
Keyword(s):  
Brassica Napus ◽  
Genetic Locus ◽  
Recognition System ◽  
Inbred Lines ◽  
The Self ◽  
Self Incompatibility ◽  
S Locus ◽  
S Haplotype ◽  
Self Compatibility

Self-incompatibility (SI) is a pollen-stigma recognition system controlled by a single and highly polymorphic genetic locus known as the S-locus. The S-locus exists in all Brassica napus (B. napus, AACC), but natural B. napus accessions are self-compatible. About 100 and 50 S haplotypes exist in Brassica rapa (AA) and Brassica oleracea (CC), respectively. However, S haplotypes have not been detected in B. napus populations. In this study, we detected the S haplotype distribution in B. napus and ascertained the function of a common S haplotype BnS-6 through genetic transformation. BnS-1/BnS-6 and BnS-7/BnS-6 were the main S haplotypes in 523 B. napus cultivars and inbred lines. The expression of SRK in different S haplotypes was normal (the expression of SCR in the A subgenome affected the SI phenotype) while the expression of BnSCR-6 in the C subgenome had no correlation with the SI phenotype in B. napus. The BnSCR-6 protein in BnSCR-6 overexpressed lines was functional, but the self-compatibility of overexpressed lines did not change. The low expression of BnSCR-6 could be a reason for the inactivation of BnS-6 in the SI response of B. napus. This study lays a foundation for research on the self-compatibility mechanism and the SI-related breeding in B. napus.

scholarly journals Genetic and Molecular Characterization of a Self-Compatible Brassica rapa Line Possessing a New Class II S Haplotype

Plants ◽  
2021 ◽  
Vol 10 (12) ◽  
pp. 2815
Author(s):  
Bing Li ◽  
Xueli Zhang ◽  
Zhiquan Liu ◽  
Lulin Wang ◽  
Liping Song ◽  
...  
Keyword(s):  
Amino Acid ◽  
De Novo ◽  
Class Ii ◽  
Transcriptional Level ◽  
Self Incompatibility ◽  
S Locus ◽  
Multiple Sequence ◽  
Pak Choi ◽  
New Class ◽  
S Haplotype

Most flowering plants have evolved a self-incompatibility (SI) system to maintain genetic diversity by preventing self-pollination. The Brassica species possesses sporophytic self-incompatibility (SSI), which is controlled by the pollen- and stigma-determinant factors SP11/SCR and SRK. However, the mysterious molecular mechanism of SI remains largely unknown. Here, a new class II S haplotype, named BrS-325, was identified in a pak choi line ‘325’, which was responsible for the completely self-compatible phenotype. To obtain the entire S locus sequences, a complete pak choi genome was gained through Nanopore sequencing and de novo assembly, which provided a good reference genome for breeding and molecular research in B. rapa. S locus comparative analysis showed that the closest relatives to BrS-325 was BrS-60, and high sequence polymorphism existed in the S locus. Meanwhile, two duplicated SRKs (BrSRK-325a and BrSRK-325b) were distributed in the BrS-325 locus with opposite transcription directions. BrSRK-325b and BrSCR-325 were expressed normally at the transcriptional level. The multiple sequence alignment of SCRs and SRKs in class II S haplotypes showed that a number of amino acid variations were present in the contact regions (CR II and CR III) of BrSCR-325 and the hypervariable regions (HV I and HV II) of BrSRK-325s, which may influence the binding and interaction between the ligand and the receptor. Thus, these results suggested that amino acid variations in contact sites may lead to the SI destruction of a new class II S haplotype BrS-325 in B. rapa. The complete SC phenotype of ‘325’ showed the potential for practical breeding application value in B. rapa.

Identification of a Ubiquitin-Binding Structure in the S-Locus F-Box Protein Controlling S-RNase-Based Self-Incompatibility

2012 ◽  
Vol 39 (2) ◽  
pp. 93-102 ◽  
Author(s):  
Guang Chen ◽  
Bin Zhang ◽  
Lijing Liu ◽  
Qun Li ◽  
Yu'e Zhang ◽  
...  
Keyword(s):  
Self Incompatibility ◽  
S Locus ◽  
Ubiquitin Binding ◽  
F Box Protein ◽  
Binding Structure
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