Identification and characterization of pin and thrum alleles of two genes that co-segregate with the Primula S locus

Plants have many ways to regulate the type of pollen that arrives on the stigma surface. Once there, further control mechanisms regulate compatibility. The latter controls are largely based on biochemical interactions that support compatible pollination and prevent incompatible matings. S–RNase–based self–incompatibility (SI) systems are the most phylogenetically widespread mechanisms for controlling pollination. Studies of Nicotiana establish a firm link between SI and unilateral interspecific incompatibility. Although implicated in both inter– and intraspecific compatibility, S–RNase operates through at least three distinct genetic mechanisms that differ in their dependence on non–S–RNase factors. Identification and characterization of these non–S–RNase factors is currently an area of active research. Searching for genetic and biochemical interactions with S–RNase can identify candidate non–S–RNase factors. HT–protein is one factor that is required for S –allele–specific pollen rejection in the Solanaceae. Major style arabinogalactan proteins such as TTS interact biochemically with S–RNase. These glycoproteins are known to interact with compatible pollen tubes and have long been suggested as possible recognition molecules. Their binding to S–RNase implies a link between stylar systems for compatibility and incompatibility. Thus, genetic and biochemical studies suggest a highly networked picture of pollen–pistil interactions.

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Genomic Organization of the S Locus: Identification and Characterization of Genes in SLG/SRK Region of S9 Haplotype of Brassica campestris (syn. rapa)

Genetics ◽

10.1093/genetics/153.1.391 ◽

1999 ◽

Vol 153 (1) ◽

pp. 391-400 ◽

Cited By ~ 7

Author(s):

Go Suzuki ◽

Naoko Kai ◽

Tamaki Hirose ◽

Kiichi Fukui ◽

Takeshi Nishio ◽

...

Keyword(s):

Brassica Campestris ◽

Protein A ◽

S Locus ◽

Cysteine Rich Protein ◽

Pollen Coat ◽

Genes Encoding ◽

Gene Rich Region ◽

Identification And Characterization ◽

S Locus Glycoprotein

Abstract 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 S9 haplotype of Brassica campestris (syn. rapa) and identified 10 genes in addition to the four previously identified (SLG9, SRK9, 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 SLG9. 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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Self-Incompatibility in Brassicaceae: Identification and Characterization of SRK-Like Sequences Linked to the S-Locus in the Tribe Biscutelleae

G3 Genes|Genome|Genetics ◽

10.1534/g3.114.010843 ◽

2014 ◽

Vol 4 (6) ◽

pp. 983-992 ◽

Cited By ~ 7

Author(s):

Jean-Baptiste Leducq ◽

Célia C Gosset ◽

Rita Gries ◽

Kevin Calin ◽

Éric Schmitt ◽

...

Keyword(s):

Self Incompatibility ◽

S Locus ◽

Identification And Characterization

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Identification and characterization of S-RNase genes and S-genotypes in Prunus and Malus species

Canadian Journal of Plant Science ◽

10.4141/cjps-2014-254 ◽

2015 ◽

Vol 95 (2) ◽

pp. 213-225 ◽

Cited By ~ 7

Author(s):

Chao Gu ◽

Lu Wang ◽

Schuyler S. Korban ◽

Yuepeng Han

Keyword(s):

Genetic Variation ◽

Fruit Trees ◽

Structural Features ◽

S Locus ◽

Prunus Species ◽

Variable Regions ◽

Malus Species ◽

Wild Accessions ◽

Identification And Characterization

Gu, C., Wang, L., Korban, S. S. and Han, Y. 2015. Identification and characterization of S-RNase genes and S-genotypes in Prunus and Malus species. Can. J. Plant Sci. 95: 213–225. Most Rosaceae fruit trees such as Prunus and Malus species exhibit gametophytic self-incompatibility that is genetically controlled by the S-locus. In turn, the S-locus contains at least two tightly-linked S-determinant genes, a pistil S-RNase and a pollen SFB. In this study, S-genotypes of 120 cultivated and wild Prunus accessions (peach) and seven wild Malus accessions (crabapple) have been characterized. Among cultivated Prunus genotypes, four S-RNase alleles, designated S 1 , S 2 , S 3 , and S 4 , have been identified, and they share typical structural features of S-RNases from all other self-incompatible Prunus species. Four S-genotypes, S 1 S 2 , S 1 S 3 , S 1 S 4 , and S 2 S 2 , were identified in peach cultivars, while only one S-genotype S 1 S 2 for wild Prunus species. The S 1 S 2 genotype is predominant in peach cultivars, accounting for 58.3% of all evaluated accessions. Similarly, four SFB alleles were identified in peach cultivars and wild accessions. However, all the four SFB alleles encode truncated proteins due to a frame-shift mutation, resulting in loss of hyper-variable and/or variable regions. For Malus species, a total of 14 S-RNase alleles are identified, and of those, two alleles encode truncated proteins. Overall, the genetic variation of both S-RNase and SFB genes in peach is significantly lower than that of S-RNase and SFB genes in self-incompatible Malus and/or Prunus species. The relationship between the genetic variation of SFB genes and the diversification of S-RNase genes in Rosaceae is also discussed.

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