Cellular Mechanisms for Pollen Tube Growth Inhibition in Gametophytic Self-incompatibility

Graaf, Barend H. J. de; Lee, Chris; McClure, Bruce; Franklin‐Tong, Vernonica E.

doi:10.1007/7089_050

Cited by 6 publications

(2 citation statements)

References 61 publications

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“…Self-incompatibility (SI) is a genetic mechanism, usually controlled by a single highly polymorphic locus called the S -locus; each polymorphic variant is referred to as an S -allele [ 45 ]. SI allows a pistil to recognize and reject self-pollen prior to fertilization, based on biochemical interactions between pollen and pistils [ 46 , 47 ]. In the Solanaceae, SI disrupts the growth of pollen tubes that have an S -allele in common with the pistil they pollinate [ 48 , 49 ] thus avoiding fertilization.…”

Section: Introductionmentioning

confidence: 99%

Inbreeding depression in Solanum carolinense (Solanaceae), a species with a plastic self-incompatibility response

2008

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BackgroundSolanum carolinense (horsenettle) is a highly successful weed with a gametophytic self-incompatibility (SI) system. Previous studies reveal that the strength of SI in S. carolinense is a plastic trait, associated with particular S-alleles. The importance of this variation in self-fertility on the ability of horsenettle to found and establish new populations will depend, to a large extent, on the magnitude of inbreeding depression. We performed a series of greenhouse and field experiments to determine the magnitude of inbreeding depression in S. carolinense, whether inbreeding depression varies by family, and whether the estimates of inbreeding depression vary under field and greenhouse conditions. We performed a series of controlled self- and cross-pollinations on 16 genets collected from a large population in Pennsylvania to obtain progeny with different levels of inbreeding. We grew the selfed and outcrossed progeny in the greenhouse and under field conditions and recorded various measures of growth and reproductive output.ResultsIn the greenhouse study we found (1) a reduction in flower, fruit and seed production per fruit in inbred (selfed) progeny when compared to outbred (outcrossed) progeny; (2) a reduction in growth of resprouts obtained from rhizome cuttings of selfed progeny; and (3) an increase in the ability to self-fertilize in the selfed progeny. In the field, we found that (1) outcrossed progeny produced more leaves than their selfed siblings; (2) herbivory seems to add little to inbreeding depression; and (3) outcrossed plants grew faster and were able to set more fruits than selfed plants.ConclusionSolanum carolinense experiences low levels of inbreeding depression under greenhouse conditions and slightly more inbreeding depression under our field conditions. The combined effects of low levels of inbreeding depression and plasticity in the strength of SI suggest that the production of selfed progeny may play an important role in the establishment of new populations of S. carolinense.

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Section: Introductionmentioning

confidence: 99%

Inbreeding depression in Solanum carolinense (Solanaceae), a species with a plastic self-incompatibility response

2008

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“…Although a variety of models focused on ubiquitylation have been explored, it is exactly still unclear how the S-RNase based system operates at the cellular level. In Papaver, entirely different S-proteins act as signaling ligands that trigger a Ca 2+ -dependent signaling cascade that results in programmed cell death (PCD) (de Graaf et al 2006).…”

Section: Introductionmentioning

confidence: 99%

Influence of endogenous and exogenous RNases on the variation of pollen cytosolic-free Ca2+ in Pyrus serotina Rehd

Zhang

Yang

et al. 2007

Acta Physiol Plant

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The objective of this study was to examine whether S-RNase plays a specific role in the pre-germinated Pyrus pollen. Effects of exogenous RNase and endogenous S-RNase on concentration of cytosolic-free calcium ([Ca 2+ ] i ) variation of pre-germinated Pyrus pollen were studied. [Ca 2+ ] i variation caused by different RNases were complex. In 1 h after being cultured, exogenous RNase, RNase T 1 and RNase A, and endogenous incompatible 'Hohsui' RNase promoted the [Ca 2+ ] i of 'Hohsui' pollen. Acid proteins of 'Hohsui' had no remarkable influence on the [Ca 2+ ] i of self-pollen. Endogenous compatible 'Kohsui' RNase reduced the [Ca 2+ ] i of 'Hohsui' pollen, but compatible 'Hohsui' RNase can stimulate the [Ca 2+ ] i of 'Kohsui' pollen. RNase T 1 , RNase A and incompatible 'Kohsui' S-RNase can also make 'Kohsui' pollen [Ca 2+ ] i increase. Different from 'Hohsui' pollen, acid proteins of 'Hohsui' pull down the 'Kohsui' pollen [Ca 2+ ] i remarkably. Conclusion can be made that during the prophase of pollen germination, endogenous S-RNase has no specific effect on pollen [Ca 2+ ] i changes.

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The effect of sheltered load on reproduction in Solanum carolinense, a species with variable self-incompatibility

2009

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In previous studies, we have investigated the strength of self-incompatibility (SI) in Solanum carolinense, a highly successful weed with a fully functional SI system that inhabits early successional and other disturbed habitats. We have found that the SI response in S. carolinense is a plastic trait-its strength being affected by the age of the flowers, and the presence of developing fruits and that there are genetic differences among families in their self-fertility. However, in species with a fully functional SI response, selfing would not be that common. As a result, deleterious recessives scattered though the genome of horsenettle are only occasionally exposed to selection. It has been suggested that deleterious recessives accumulate near S-alleles in strong SI species because the S-locus is located in a non-recombining region of the genome and because strong S-alleles are never in the homozygous state, thus sheltering some of the genetic load near the S-locus from selection. We performed a series of laboratory and greenhouse experiments to determine the extent to which sheltered load adds to the overall magnitude of inbreeding depression in horsenettle. Specifically, we amplified and sequenced the S-alleles from 16 genets collected from a large population in Pennsylvania and performed a series of controlled self-pollinations. We then grew the selfed progeny in the greenhouse; recorded various measures of growth and reproductive output; and amplified and sequenced their S-allele(s). We found that the heterozygous progeny of self-pollinations produce more flowers and have a greater ability to set both self and cross seed than S-homozygous progeny. We also found evidence of variation in the magnitude of load among S-alleles. These results suggest that sheltered load might slow the fixation of weak (partially compatible) S-alleles in this population, thus adding to the maintenance of a mixed mating system rather than leading to the fixation of the selfing alleles.

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Cellular Mechanisms for Pollen Tube Growth Inhibition in Gametophytic Self-incompatibility

Cited by 6 publications

References 61 publications

Inbreeding depression in Solanum carolinense (Solanaceae), a species with a plastic self-incompatibility response

Inbreeding depression in Solanum carolinense (Solanaceae), a species with a plastic self-incompatibility response

Influence of endogenous and exogenous RNases on the variation of pollen cytosolic-free Ca2+ in Pyrus serotina Rehd

The effect of sheltered load on reproduction in Solanum carolinense, a species with variable self-incompatibility

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