scholarly journals Gametophytic self-incompatibility in Andean capuli (Prunus serotina subsp. capuli): allelic diversity at the S-RNase locus influences normal pollen-tube formation during fertilization

PeerJ ◽  
2020 ◽  
Vol 8 ◽  
pp. e9597
Author(s):  
Milton Gordillo-Romero ◽  
Lisa Correa-Baus ◽  
Verónica Baquero-Méndez ◽  
María de Lourdes Torres ◽  
Carlos Vintimilla ◽  
...  
Keyword(s):  
Pollen Tube ◽  
Allelic Diversity ◽  
Pollen Tubes ◽  
Tube Formation ◽  
Rnase A ◽  
Prunus Serotina ◽  
Self Incompatibility ◽  
S Locus ◽  
Normal Pollen ◽  
S Alleles

Capuli (Prunus serotina subsp. capuli) is a tree species that is widely distributed in the northern Andes. In Prunus, fruit set and productivity appears to be limited by gametophytic self-incompatibility (GSI) which is controlled by the S-Locus. For the first time, this research reveals the molecular structure of the capuli S-RNase (a proxy for S-Locus diversity) and documents how S-Locus diversity influences GSI in the species. To this end, the capuli S-RNase gene was amplified and sequenced in order to design a CAPS (Cleaved Amplified Polymorphic Sequence) marker system that could unequivocally detect S-alleles by targeting the highly polymorphic C2–C3 S-RNase intra-genic region. The devised system proved highly effective. When used to assess S-Locus diversity in 15 P. serotina accessions, it could identify 18 S-alleles; 7 more than when using standard methodologies for the identification of S-alleles in Prunus species. CAPS marker information was subsequently used to formulate experimental crosses between compatible and incompatible individuals (as defined by their S-allelic identity). Crosses between heterozygote individuals with contrasting S-alleles resulted in normal pollen tube formation and growth. In crosses between individuals with exactly similar S-allele identities, pollen tubes often showed morphological alterations and arrested development, but for some (suspected) incompatible crosses, pollen tubes could reach the ovary. The latter indicates the possibility of a genotype-specific breakdown of GSI in the species. Overall, this supports the notion that S-Locus diversity influences the reproductive patterns of Andean capuli and that it should be considered in the design of orchards and the production of basic propagation materials.

scholarly journals Testing of self-(in)compatibility in apricot cultivars from European breeding programmes

2013 ◽  
Vol 40 (No. 2) ◽  
pp. 65-71 ◽  
Author(s):  
D. Milatović ◽  
D. Nikolić ◽  
B. Krška
Keyword(s):  
Fluorescence Microscopy ◽  
Pollen Tube ◽  
Pollen Tube Growth ◽  
Reliable Method ◽  
Pollen Tubes ◽  
Tube Growth ◽  
Self Incompatibility ◽  
Breeding Programmes

Self-(in)compatibility was tested in 40 new apricot cultivars from European breeding programmes. Pollen-tube growth in pistils from laboratory pollinations was analysed using the fluorescence microscopy. Cultivars were considered self-compatible if at least one pollen tube reached the ovary in the majority of pistils. Cultivars were considered self- incompatible if the growth of pollen tubes in the style stopped along with formation of characteristic swellings. Of the examined cultivars, 18 were self-compatible and 22 were self-incompatible. Fluorescence microscopy provides a relatively rapid and reliable method to determine self-incompatibility in apricot cultivars.      

Ultrastructural Aspects of the Self-Incompatibility Mechanism in Lycopersicum Peruvianum Mill

1973 ◽  
Vol 12 (2) ◽  
pp. 403-419 ◽  
Author(s):  
D. DE NETTANCOURT ◽  
M. DEVREUX ◽  
A. BOZZINI ◽  
M. CRESTI ◽  
E. PACINI ◽  
...  
Keyword(s):  
Pollen Tube ◽  
Tube Wall ◽  
Degradation Mechanism ◽  
Embryo Sac ◽  
Pollen Tubes ◽  
Self Incompatibility ◽  
Weak Reaction ◽  
General Hypothesis ◽  
Incompatible Pollen ◽  
Compatible Pollen

The experimental results obtained show that the tip of the incompatible pollen tube bursts open after the outer-wall has considerably expanded in the intercellular spaces of the conducting tissue and the inner-wall has disappeared and numerous particles have accumulated in the tube cytoplasm. These particles, which measure approximately 0.2 µm in diameter and give a weak reaction to the test of Thiéry, differ in many respects from the vesicles normally present in compatible pollen tubes growing through the style; they appear to resemble, in some cases, the spheres which are discharged by the compatible pollen tubes after they have reached the embryo-sac. It is considered that these observations support the current belief that the tube wall is the site of action for the incompatibility proteins and suggest that self-incompatibility is not a passive process resulting from lack of growth stimulation but an active event which leads to the destruction of the incompatible pollen tubes. The degradation mechanism involved appears similar to the one which enables the compatible pollen tube to release its contents in the degenerated synergid and presents some analogies with the lytic process taking place in virus-infected cells. The general hypothesis is presented that the particles observed in the cytoplasm of self-incompatible pollen tubes consist of a mixture of incompatibility proteins and of basic constituents of the tube wall.

Serological reactions of pollen incompatibility substances

1952 ◽  
Vol 140 (898) ◽  
pp. 127-135 ◽  
Keyword(s):  
Pollen Tube ◽  
Pollen Tubes ◽  
Cross Reactions ◽  
Antigenic Stimulus ◽  
Incompatible Pollen ◽  
S Alleles ◽  
Incompatibility Reaction

Pollen extracts of four different incompatibility genotypes S 2.4 , S 2.6 , S 3.4 , S 3.6 of Oenothera organensis were injected into rabbits to produce antisera. All the unabsorbed antisera gave precipitin reactions with all pollen extracts but the homologous extracts gave stronger reactions. Antisera which had been fully absorbed with pollen extracts heterologous in respect of S alleles gave strong reactions only with extracts which had S alleles in common with the antisera. The results of twenty-five different combinatorial tests, with the exception of two cross reactions, agree with the theory that the S alleles produce specific substances in the pollen each of which is antigenically different. Stigmas pollinated twice at a 4 hour interval with incompatible pollen showed that the pollen tubes from the second pollination were not affected by the presence of the first lot. This shows that the stylar incompatibility substance is pre-formed and is not the result of an antigenic stimulus from the pollen tubes. Pollen-tube inhibitions in the style due to the incompatibility reaction is complete and irreversible at 31°C in 30 min and after 0⋅2 to 0⋅3 mm growth.

scholarly journals Balancing selection and the crossing of fitness valleys in structured populations: diversification in the gametophytic self-incompatibility system

2021 ◽  
Author(s):  
Roman Stetsenko ◽  
Thomas Brom ◽  
Vincent Castric ◽  
Sylvain Billiard
Keyword(s):  
Population Structure ◽  
Allelic Diversity ◽  
Structured Populations ◽  
The Self ◽  
Population Subdivision ◽  
Island Population ◽  
Single Mutation ◽  
Self Incompatibility ◽  
S Locus ◽  
Incompatibility Locus

The self-incompatibility locus (S-locus) of flowering plants displays a striking allelic diversity. How such a diversity has emerged remains unclear. In this paper, we performed numerical simulations in a finite island population genetics model to investigate how population subdivision affects the diversification process at a S-locus, given that the two-genes architecture typical of S-loci involves the crossing of a fitness valley. We show that population structure increases the number of self-incompatibility haplotypes (S-haplotypes) maintained in the whole metapopulation, but at the same time also slightly reduces the parameter range allowing for their diversification. This increase is partly due to a reinforcement of the diversification and replacement dynamics of S-haplotypes within and among demes. We also show that the two-genes architecture leads to a higher diversity compared with a simpler genetic architecture where new S-haplotypes appear in a single mutation step. We conclude that population structure helps explain the large allelic diversity at the self-incompatibility locus. Overall, our results suggest that population subdivision can act in two opposite directions: it makes easier S-haplotypes diversification but increases the risk that the SI system is lost.

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