Dataset Information

Elucidation of the genetic architecture of self-incompatibility in olive: Evolutionary consequences and perspectives for orchard management.

ABSTRACT: The olive (Olea europaea L.) is a typical important perennial crop species for which the genetic determination and even functionality of self-incompatibility (SI) are still largely unresolved. It is still not known whether SI is under gametophytic or sporophytic genetic control, yet fruit production in orchards depends critically on successful ovule fertilization. We studied the genetic determination of SI in olive in light of recent discoveries in other genera of the Oleaceae family. Using intra- and interspecific stigma tests on 89 genotypes representative of species-wide olive diversity and the compatibility/incompatibility reactions of progeny plants from controlled crosses, we confirmed that O. europaea shares the same homomorphic diallelic self-incompatibility (DSI) system as the one recently identified in Phillyrea angustifolia and Fraxinus ornus. SI is sporophytic in olive. The incompatibility response differs between the two SI groups in terms of how far pollen tubes grow before growth is arrested within stigma tissues. As a consequence of this DSI system, the chance of cross-incompatibility between pairs of varieties in an orchard is high (50%) and fruit production may be limited by the availability of compatible pollen. The discovery of the DSI system in O. europaea will undoubtedly offer opportunities to optimize fruit production.

SUBMITTER: Saumitou-Laprade P

PROVIDER: S-EPMC5680433 | biostudies-literature | 2017 Oct

REPOSITORIES: biostudies-literature

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Elucidation of the genetic architecture of self-incompatibility in olive: Evolutionary consequences and perspectives for orchard management.

Saumitou-Laprade Pierre P Vernet Philippe P Vekemans Xavier X Billiard Sylvain S Gallina Sophie S Essalouh Laila L Mhaïs Ali A Moukhli Abdelmajid A El Bakkali Ahmed A Barcaccia Gianni G Alagna Fiammetta F Mariotti Roberto R Cultrera Nicolò G M NGM Pandolfi Saverio S Rossi Martina M Khadari Bouchaïb B Baldoni Luciana L

Evolutionary applications 20170520 9

The olive (<i>Olea europaea</i> L.) is a typical important perennial crop species for which the genetic determination and even functionality of self-incompatibility (SI) are still largely unresolved. It is still not known whether SI is under gametophytic or sporophytic genetic control, yet fruit production in orchards depends critically on successful ovule fertilization. We studied the genetic determination of SI in olive in light of recent discoveries in other genera of the Oleaceae family. Usi ...[more]

PMID: 29151878

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Project description:Self-incompatibility (SI) in flowering plants potentially represents a major obstacle for sexual reproduction, especially when the number of S-alleles is low. The situation is extreme in the commercially important olive tree, where in vitro pollination assays suggested the existence of a diallelic SI (DSI) system involving only two groups (G1 and G2). Varieties belonging to the same SI group cannot fertilize each other, such that successful fruit production is predicted to require pollination between varieties of different groups. To test this prediction, we explored the extent to which the DSI system determines fertilization patterns under field conditions. One hundred and seventeen olive cultivars were first genotyped using 10 highly polymorphic dinucleotide Simple Sequence Repeat (SSR) markers to ascertain varietal identity. Cultivars were then phenotyped through controlled pollination tests to assign each of them to one of the two SI groups. We then collected and genotyped 1440 open pollinated embryos from five different orchards constituted of seven local cultivars with known group of incompatibility groups. Embryos genotype information were used: (i) to assign embryos to the most likely pollen donor genotype in the neighbourhood using paternity analysis, and (ii) to compare the composition of the pollen cloud genetic among recipient trees in the five sites. The paternity analysis showed that the DSI system is the main determinant of fertilization success under field open pollination conditions: G1 cultivars sired seeds exclusively on G2 cultivars, and reciprocally. No self-fertilization events were observed. Our results demonstrate that DSI is a potent force determining pollination success among varieties within olive orchards used for production. They have the potential to improve management practices by guiding the selection of compatible varieties to avoid planting orchards containing sets of varieties with strongly unbalanced SI groups, as these would lead to suboptimal olive production.

Project description:BACKGROUND:Papaver rhoeas possesses a gametophytic self-incompatibility (SI) system not homologous to any other SI mechanism characterized at the molecular level. Four previously published full length stigmatic S-alleles from the genus Papaver exhibited remarkable sequence divergence, but these studies failed to amplify additional S-alleles despite crossing evidence for more than 60 S-alleles in Papaver rhoeas alone. METHODOLOGY/PRINCIPAL FINDINGS:Using RT-PCR we identified 87 unique putative stigmatic S-allele sequences from the Papaveraceae Argemone munita, Papaver mcconnellii, P. nudicuale, Platystemon californicus and Romneya coulteri. Hand pollinations among two full-sib families of both A. munita and P. californicus indicate a strong correlation between the putative S-genotype and observed incompatibility phenotype. However, we also found more than two S-like sequences in some individuals of A. munita and P. californicus, with two products co-segregating in both full-sib families of P. californicus. Pairwise sequence divergence estimates within and among taxa show Papaver stigmatic S-alleles to be the most variable with lower divergence among putative S-alleles from other Papaveraceae. Genealogical analysis indicates little shared ancestral polymorphism among S-like sequences from different genera. Lack of shared ancestral polymorphism could be due to long divergence times among genera studied, reduced levels of balancing selection if some or all S-like sequences do not function in incompatibility, population bottlenecks, or different levels of recombination among taxa. Preliminary estimates of positive selection find many sites under selective constraint with a few undergoing positive selection, suggesting that self-recognition may depend on amino acid substitutions at only a few sites. CONCLUSIONS/SIGNIFICANCE:Because of the strong correlation between genotype and SI phenotype, sequences reported here represent either functional stylar S-alleles, tightly linked paralogs of the S-locus or a combination of both. The considerable complexity revealed in this study shows we have much to learn about the evolutionary dynamics of self-incompatibility systems.

Project description:Background and objectivesPatients with CKD are asked to perform self-management tasks including dietary changes, adhering to medications, avoiding nephrotoxic drugs, and self-monitoring hypertension and diabetes. Given the effect of aging on functional capacity, self-management may be especially challenging for older patients. However, little is known about the specific challenges older adults face maintaining CKD self-management regimens.Design, setting, participants, & measurementsWe conducted an exploratory qualitative study designed to understand the relationship among factors facilitating or impeding CKD self-management in older adults. Six focus groups (n=30) were held in August and September of 2014 with veterans≥70 years old with moderate-to-severe CKD receiving nephrology care at the Atlanta Veterans Affairs Medical Center. Grounded theory with a constant comparative method was used to collect, code, and analyze data.ResultsParticipants had a mean age (range) of 75.1 (70.1-90.7) years, 60% were black, and 96.7% were men. The central organizing concept that emerged from these data were managing complexity. Participants typically did not have just one chronic condition, CKD, but a number of commonly co-occurring conditions. Recommendations for CKD self-management therefore occurred within a complex regimen of recommendations for managing other diseases. Participants identified overtly discordant treatment recommendations across chronic conditions (e.g., arthritis and CKD). Prioritization emerged as one effective strategy for managing complexity (e.g., focusing on BP control). Some patients arrived at the conclusion that they could group concordant recommendations to simplify their regimens (e.g., protein restriction for both gout and CKD).ConclusionsAmong older veterans with moderate-to-severe CKD, multimorbidity presents a major challenge for CKD self-management. Because virtually all older adults with CKD have multimorbidity, an integrated treatment approach that supports self-management across commonly occurring conditions may be necessary to meet the needs of these patients.

Project description:BACKGROUND: A great deal of data has accumulated on signalling pathways. These large datasets are thought to contain much implicit information on their molecular structure, interaction and activity information, which provides a picture of intricate molecular networks believed to underlie biological functions. While tremendous advances have been made in trying to understand these systems, how information is transmitted within them is still poorly understood. This ever growing amount of data demands we adopt powerful computational techniques that will play a pivotal role in the conversion of mined data to knowledge, and in elucidating the topological and functional properties of protein - protein interactions. RESULTS: A computational framework is presented which allows for the description of embedded networks, and identification of common shared components thought to assist in the transmission of information within the systems studied. By employing the graph theories of network biology - such as degree distribution, clustering coefficient, vertex betweenness and shortest path measures - topological features of protein-protein interactions for published datasets of the p53, nuclear factor kappa B (NF-kappaB) and G1/S phase of the cell cycle systems were ascertained. Highly ranked nodes which in some cases were identified as connecting proteins most likely responsible for propagation of transduction signals across the networks were determined. The functional consequences of these nodes in the context of their network environment were also determined. These findings highlight the usefulness of the framework in identifying possible combination or links as targets for therapeutic responses; and put forward the idea of using retrieved knowledge on the shared components in constructing better organised and structured models of signalling networks. CONCLUSION: It is hoped that through the data mined reconstructed signal transduction networks, well developed models of the published data can be built which in the end would guide the prediction of new targets based on the pathway's environment for further analysis. Source code is available upon request.

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Dataset Information

Elucidation of the genetic architecture of self-incompatibility in olive: Evolutionary consequences and perspectives for orchard management.

Publications

Elucidation of the genetic architecture of self-incompatibility in olive: Evolutionary consequences and perspectives for orchard management.

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