What Genealogies of S-alleles Tell Us

Kohn, Joshua R.

doi:10.1007/978-3-540-68486-2_5

Cited by 9 publications

(17 citation statements)

References 77 publications

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“…The tomato plant family (Solanaceae) has served as a model system for the study of GSI in angiosperms from both a mechanistic (reviewed in McClure, 2004) and a population genetic perspective (Igic et al, 2004;Kohn, 2008). In particular, the development of reverse-transcriptase PCR methods for amplifying S-alleles using RNA extracted from styles (Richman et al, 1995) has resulted in a number of population surveys of S-RNase variation in several species and genera (Lycium, Savage and Miller, 2006, Miller et al, 2008Nicotiana, Roldán et al, 2010;Petunia, Wang et al, 2001;Physalis, Richman et al 1996, Lu, 2002Solanum, Richman et al, 1995, Igic et al, 2007, Mena-Ali and Stephenson, 2007Witheringia, Stone and Pierce, 2005).…”

Section: Introductionmentioning

confidence: 99%

Functional gametophytic self-incompatibility in a peripheral population of Solanum peruvianum (Solanaceae)

Miller

Kostyun

2010

Heredity

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The transition from self-incompatibility to self-compatibility is a common transition in angiosperms often reported in populations at the edge of species range limits. Geographically distinct populations of wild tomato species (Solanum section Lycopersicon (Solanaceae)) have been described as polymorphic for mating system with both self-incompatible and self-compatible populations. Using controlled pollinations and sequencing of the S-RNase mating system gene, we test the compatibility status of a population of S. peruvianum located near its southern range limit. Pollinations among plants of known genotypes revealed strong selfincompatibility; fruit set following compatible pollinations was significantly higher than following incompatible pollinations for all tested individuals. Sequencing of the S-RNase gene in parents and progeny arrays was also as predicted under self-incompatibility. Molecular variation at the S-RNase locus revealed a diverse set of alleles, and heterozygosity in over 500 genotyped individuals. We used controlled crosses to test the specificity of sequences recovered in this study; in all cases, results were consistent with a unique allelic specificity for each tested sequence, including two alleles sharing 92% amino-acid similarity. Site-specific patterns of selection at the S-RNase gene indicate positive selection in regions of the gene associated with allelic specificity determination and purifying selection in previously characterized conserved regions. Further, there is broad convergence between the present and previous studies in specific amino-acid positions inferred to be evolving under positive selection.

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Section: Introductionmentioning

confidence: 99%

Functional gametophytic self-incompatibility in a peripheral population of Solanum peruvianum (Solanaceae)

Miller

Kostyun

2010

Heredity

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“…Acanthaceae, Oleaceae, Rubiaceae, Saxifragaceae; Igic, Lande & Kohn, 2008). Similarly, sporophytic self‐incompatibility, in which the incompatibility reaction is determined by the parental plant, is found in lineages likely to have had ancestors with gametophytic self‐incompatibility and probably evolved from immediate ancestors possessing self‐compatibility (Allen & Hiscock, 2008; Kohn, 2008), a view consistent with the divergent molecular basis for sporophytic self‐incompatibility and gametophytic incompatibility systems (Allen & Hiscock, 2008). Because loss of homomorphic self‐incompatibility appears to be unidirectional (Igic, Lande & Kohn, 2008), subsequent selection for increased outcrossing in these lineages via protandry or herkogamy (Anderson, 1973; Lloyd & Webb, 1992a) or, alternatively, diallelic heteromorphic self‐incompatibility (Charlesworth & Charlesworth, 1979), may have led to the evolution of heterostyly.…”

Section: Physiological and Molecular Basis For Self‐incompatibility Imentioning

confidence: 88%

“…Homomorphic multi‐allelic self‐incompatibility has received far more attention than heterostyly (e.g. Igic & Kohn, 2001; Hiscock & McInnis, 2003; Allen & Hiscock, 2008; Franklin‐Tong, 2008; Kohn, 2008). These studies have shown diverse mechanisms underlying homomorphic multi‐allelic incompatibility and suggest multiple evolutionary origins for these systems (Allen & Hiscock, 2008).…”

Section: Physiological and Molecular Basis For Self‐incompatibility Imentioning

confidence: 99%

The different forms of flowers - what have we learned since Darwin?

Weller

2009

Botanical Journal of the Linnean Society

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Darwin's book, The Different Forms of Flowers on Plants of the Same Species, has stimulated an extraordinary amount of original research since its publication in 1877. In his book, Darwin focused primarily on heterostylous reproductive systems in flowering plants, in which two or three reproductive morphs with reciprocal placement of anthers and stigmas occur in populations. These morphs are usually self-incompatible and cross-incompatible with individuals possessing the same reproductive morph. Many of the papers on heterostyly published since Forms of Flowers appeared have focused on the questions raised by Darwin about the evolution and function of heterostyly. Darwin's hypothesis that heterostyly promotes cross-pollination between different morphs has been largely substantiated, despite the difficulties in finding the ideal experimental system to address this question. Heterostyly is now known to occur in many more plant families than at the time Forms of Flowers was published and, as expected, the heterostylous syndrome is now defined more broadly than in Darwin's time. The origin of heterostyly remains an area of active research, with hypotheses stressing either the evolution of heteromorphic selfincompatibility as the first step in the evolution of this reproductive system or, alternatively, the evolution of the reciprocal features of floral morphology. Phylogenetic approaches, combined with studies on the physiological and molecular genetic basis of heterostyly, offer promise in helping to resolve questions about the origin of heterostyly. There is no doubt that heterostyly has evolved on multiple occasions and that self-incompatibility associated with heterostyly is unrelated to the more common multi-allelic self-incompatibility systems found in monomorphic species. Further progress in understanding conditions favouring evolution of heterostyly will depend on an increased understanding of the relation between the reciprocal morphological features of the breeding system and the nature of self-incompatibility. Almost a century and a half after the appearance of The Different Forms of Flowers on Plants of the Same Species, heterostyly remains an active area of research.

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“…In the Solanaceae, it has been estimated that majority of the observed Slocus polymorphisms arose before speciation from the common ancestor. This ancestor is believed to have occurred 35-45 million years ago (Ioerger et al, 1990;Richman at al., 1995Richman at al., , 1996aRichman at al., , 1996bIgic et al, 2006;Paape et al, 2008;Kohn, 2008).…”

Section: Trans-specific Evolutionmentioning

confidence: 99%

“…But Iochromina Slocus seems much more polymorphic and several lineages not represented in Physalis and Witheringia have been identified there. This means that the restriction in the S-locus number must have occurred after the most recent common ancestor of the group containing the Iochrominae and it has been estimated that the bottleneck must have occurred between 14 and 18 mya (Kohn, 2008;Paape et al, 2008).…”

Section: Long-term Population History Recorded In S-locus Polymorphismmentioning

confidence: 99%

Plant Self-Incompatibility: Or, Self-Induction of Population Genetic Diversity

Wolko¹,

Słomski²

2012

The Molecular Basis of Plant Genetic Diversity

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The Molecular Basis of Plant Genetic Diversity 74 system protects plants from pollination with pollen carrying the same S-haplotype (McClure & Franklin, 2006). Two main systems of homomorphic SI comprise: gametophytic self-incompatibility (GSI) and sporophytic self-incompatibility (SSI). In GSI, the incompatibility phenotype is determined by the pollen haploid genome. The S-locus determines S-specificity of pollen recognition and rejection, so the pollen is rejected by the GSI system when the S-haplotype is the same as one of two S-alleles of the diploid pistil. This indicates that the S-locus products readily expressed in the pistil and pollen interact with each other and determine the compatibility or incompatibility of the emerging pollen tube. In sporophytic SI, the pollen S-phenotype is determined by the diploid genome of the parental plant. Therefore, in GSI systems half-compatibility is shown between individuals that share one S-allele, while in SSI systems crosses are always fully compatible or fully incompatible (Allen & Hiscock, 2008). The SSI system has been reported in six families: Asteraceae, Berulaceae, Brassicaceae, Caryopgyllaceae, Convolvulaceae and Polemoniaceae. The molecular mechanism of the SSI has only been well characterized in Brassicaceae (see below) (Hiscock & McInnis, 2003). Studies of GSI species at the molecular level have identified two completely different SI mechanisms. One GSI mechanism, which is found in the Solanaceae, Rosaceae and Scrophulariaceae, has S-RNase as the pistil S-component and an F-box protein as the pollen S-component (see below). The second mechanism has been identified only in Papaver (poppy), where the interaction between male and female determinants transmits a cellular signal into the pollen tube, resulting in an influx of calcium cations. This influx interferes with the intracellular concentration gradient of calcium ions which exists inside the pollen tube, essential for its elongation (McClure & Franklin-Tong, 2006; Zhang & Xue, 2008).

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What Genealogies of S-alleles Tell Us

Cited by 9 publications

References 77 publications

Functional gametophytic self-incompatibility in a peripheral population of Solanum peruvianum (Solanaceae)

Functional gametophytic self-incompatibility in a peripheral population of Solanum peruvianum (Solanaceae)

The different forms of flowers - what have we learned since Darwin?

Plant Self-Incompatibility: Or, Self-Induction of Population Genetic Diversity

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