BackgroundNatural selection acts on multiple traits in an organism, and the final outcome of adaptive evolution may be constrained by the interaction of physiological and functional integration of those traits. Fatty acid composition is an important determinant of seed oil quality. In plants the relative proportions of unsaturated fatty acids in phospholipids and seed triacylglycerols often increases adaptively in response to lower growing temperatures to increase fitness. Previous work produced evidence of genetic constraints between phospholipids and triacylglycerols in the widely studied Arabidopsis lines Col and Ler, but because these lines are highly inbred, the correlations might be spurious. In this study, we grew 84 wild Arabidopsis accessions at two temperatures to show that genetic correlation between the fatty acids of the two lipid types is not expected and one should not influence the other and seed oil evolution and also tested for the adaptive response of fatty acids to latitude and temperature.ResultsAs expected no significant correlations between the two lipids classes at either growing temperature were observed. The saturated fatty acids and erucic acid of triacylglycerols followed a significant latitudinal cline, while the fatty acids in phospholipids did not respond to latitude as expected. The expected plastic response to temperature was observed for all the triacylglycerol fatty acids whereas only oleic acid showed the expected pattern in phospholipids. Considerable phenotypic variation of the fatty acids in both the lipid types was seen.ConclusionWe report the first evidence supporting adaptive evolution of seed triacylglycerols in Arabidopsis on a latitudinal cline as seen in other species and also their plastic adaptive response to growing temperature. We show that as expected there is no genetic correlations between the fatty acids in triacylglycerols and phospholipids, indicating selection can act on seed triacylglycerols without being constrained by the fatty acid requirements of the phospholipids. Phospholipid fatty acids do not respond to latitude and temperature as seen elsewhere and needs further investigation. Thus, the adaptive response of Arabidopsis and the genetic tools available for manipulating Arabidopsis, makes it an excellent system for studying seed oil evolution and also for breeding seed oil crops especially the Brassica species.

Palm oil is widely used in the food industry because of its lower cost, high oxidative stability index, long shelf-life, and a reasonable replacement of trans fats. However, increased palm oil production reduces biodiversity, damages the ecosystem, and poses health risks to humans. Unsustainable development of palm plantations has caused deforestation and loss of natural habitat, rendering many species (Sumatran orangutans, elephants, and tigers) critically endangered. Similarly, decomposition and burning of carbon-rich soil in vast and deep peatlands is increasing carbon emissions. Furthermore, excessive consumption of palmitic acid (and other saturated fats except stearic acid) increases bad cholesterol and the risk of cardiovascular diseases. Therefore, we need healthier, stable, and solid/semisolid oils at room temperature with longer shelf-life and without trans fats. Here, we review the advancements in the development of sunflower oil varieties containing high stearic (∼18%) and high oleic (∼70%) acids which makes them healthy and sustainable alternatives to palm oil. First, the high-stearic-high-oleic sunflower crops can have grain and oil yield as high as 4036 and 1685 kg/ha and oleic and stearic acid yield up to ∼73 and ∼21%. Second, high-stearic-high-oleic oils obtained from mutant and hybrid sunflower cultivars have higher oxidative stability index and therefore have better stability, quality, and functionality than regular sunflower oil. For example, the oxidative stability index of commercially available Nutrisun at 110°C is six times greater than that of regular sunflower oil. Finally, recent advances have made several mutant and hybrid cultivars with high grain and oil yield and high levels of stearic and oleic acids available. Given this progress, natural healthy high-stearic-high-oleic sunflower oil can now be grown in both the hemispheres in a sustainable manner with the currently available advanced technology and without damaging the ecosystem as is currently happening with palm oil cultivation.

Fatty acid composition is an important determinant of seed oil quality. Overall, 72 QTL for 12 fatty acid traits that control seed oil composition were identified in four recombinant inbred line (RIL) populations (Ler-0 × Sha, Ler-0 × Col-4, Ler-2 × Cvi, Ler-0 × No-0) of Arabidopsis thaliana. The identified QTL explained 3.2-79.8% of the phenotypic variance; 33 of the 59 QTL identified in the Ler-0 × Sha and the Ler-0 × Col RIL populations co-located with several a priori candidate genes for seed oil composition. QTL for fatty acids 18:1, 18:2, 22:1, and fatty acids synthesized in plastids was identified in both Ler-0 × Sha and Ler-0 × Col-4 RIL populations, and QTL for 16:0 was identified in the Ler-0 × Sha and Ler-0 × No-0 RIL populations providing strong support for the importance of these QTL in determining seed oil composition. We identified melting point QTL in three RIL populations, and fatty acid QTL collocated with two of them, suggesting that the loci could be under selection for altering the melting point of seed oils to enhance adaptation and could be useful for breeding purposes. Nuclear-cytoplasmic interactions and epistasis were rare. Analysis of the genetic correlations between these loci and other fatty acids indicated that these correlations would tend to strongly enhance selection for desirable fatty acids.

BackgroundStudies of the biogeographic distribution of seed oil content in plants are fundamental to understanding the mechanisms of adaptive evolution in plants as seed oil is the primary energy source needed for germination and establishment of plants. However, seed oil content as an adaptive trait in plants is poorly understood. Here, we examine the adaptive nature of seed oil content in 168 angiosperm families occurring in different biomes across the world. We also explore the role of multiple seed traits like seed oil content and composition in plant adaptation in a phylogenetic and nonphylogenetic context.ResultIt was observed that the seed oil content in tropical plants (28.4 %) was significantly higher than the temperate plants (24.6 %). A significant relationship between oil content and latitude was observed in three families Papaveraceae, Sapindaceae and Sapotaceae indicating that selective forces correlated with latitude influence seed oil content. Evaluation of the response of seed oil content and composition to latitude and the correlation between seed oil content and composition showed that multiple seed traits, seed oil content and composition contribute towards plant adaptation. Investigation of the presence or absence of phylogenetic signals across 168 angiosperm families in 62 clades revealed that members of seven clades evolved to have high or low seed oil content independently as they did not share a common evolutionary path.ConclusionThe study provides us an insight into the biogeographical distribution and the adaptive role of seed oil content in plants. The study indicates that multiple seed traits like seed oil content and the fatty acid composition of the seed oils determine the fitness of the plants and validate the adaptive hypothesis that seed oil quantity and quality are crucial to plant adaptation.Electronic supplementary materialThe online version of this article (doi:10.1186/s12862-016-0752-7) contains supplementary material, which is available to authorized users.

Premise Understanding the adaptive capacities of species over long timescales lies in examining the revived recent and millennia‐old resting spores buried in sediments. We show for the first time the revival, viability, and germination rate of resting spores of the diatom Chaetoceros deposited in sub‐seafloor sediments from three ages (recent: 0 to 80 years; ancient: ~1250 (Medieval Climate Anomaly) and ~6600 (Holocene Thermal Maximum) calendar year before present. Methods Recent and ancient Chaetoceros spores were revived to examine their viability and germination rate. Light and scanning electron microscopy and Sanger sequencing was done to identify the species. Results We show that ~6600 cal. year BP old Chaetoceros resting spores are still viable and that the vegetative reproduction in recent and ancient resting spores varies. The time taken to germinate is three hours to 2 to 3 days in both recent and ancient spores, but the germination rate of the spores decreased with increasing age. The germination rate of the recent spores was ~41% while that of the ancient spores were ~31% and ~12% for the ~1250 and ~6600 cal. year BP old resting spores, respectively. Based on the morphology of the germinated vegetative cells we identified the species as Chaetoceros muelleri var. subsalsum. Sanger sequences of nuclear and chloroplast markers identified the species as Chaetoceros muelleri. Conclusions We identify a unique model system, Chaetoceros muelleri var. subsalsum and show that recent and ancient resting spores of the species buried in sediments in the Baltic Sea can be revived and used for long‐term evolutionary studies.

Multiple seed oil traits are adaptive in nature and follow a gradient model. Consistent evolutionary patterns of seed oil traits were observed at the intraspecific and interspecific levels in Brassicaceae. Seed oil traits change with latitude and across biomes, suggesting selection. The absence of a phylogenetic signal for seed oil traits and the occurrence of high seed oil content in four Brassicaceae tribes provides evidence of the adaptive nature of seed oil traits in Brassicaceae.

-In the current context of boosting production of high erucic acid rapeseed, because of the wide range of its industrial applications, this literature review is designed to provide a general overview of available varieties, current knowledge of plant improvement and paths of developing research to increase competitiveness of varieties with high erucic acid content. A limited market dominated by a few companies, cropping burdens of high erucic acid rapeseed varieties among the majority "00" varieties and the still low erucic acid content in rapeseed, explains the reduced and uncompetitive varietal offers. To improve this situation, new varieties could be developed, thanks to the classical methods of selection and biotechnology.Keywords: Erucic acid / rapeseed / variety / selection / biotechnology Résumé -Colza érucique : partie 1. les pistes d'amélioration. Dans un contexte de relance de la production d'acide érucique, à partir du colza, en raison de ses nombreuses applications industrielles, ce dossier bibliographique a pour objectif de faire le point sur quelques variétés disponibles, les connaissances actuelles en matière d'amélioration des plantes et les pistes de recherche explorées pour améliorer la compétitivité des variétés éruciques. Un marché limité, dominé par quelques sociétés, les contraintes culturales des variétés riches en acide érucique parmi des variétés « 00 » majoritaires et la teneur encore limitée des graines de colza en acide érucique expliquent une offre variétale réduite et peu compétitive. Pour remédier à cette situation, de nouvelles variétés pourraient être développées, grâce aux techniques classiques de sélection et aux biotechnologies.

Microscopic marine planktons have played a major role in the Earth's ecosystem and accounts for half the globe's primary production. Predicting the fate of marine planktons is imperative to understanding how ocean life will change in future centuries and how organisms have adapted to changes in the past over long timescales (over thousands of years). Studies of revived resting spores of marine diatoms will serve as excellent proxies of environmental change in marine environments. Thus far, only about a century old marine diatom resting spores could be revived. This severely limited the use of diatom resting spores to investigate the effects of environmental perturbations over longer time scales. Here, we, for the first time report revival of thousands of years old resting spores from the deposits of ancient diatoms (Chaetoceros) in sub-seafloor sediments using a revival protocol that involved recreating the ancient environmental conditions (salinity, temperature and light). Our revived diatom resting spores samples range from recent (0-80 years) to ~7200 years old. Importantly, we also extracted the DNA from the ancient resting spores of Chaetoceros species from the Baltic Sea. Our findings will enable us to compare DNA sequence data obtained from these natural archives of resurrected organisms and provide predictive models to forecast evolutionary responses of natural populations to environmental changes resulting from natural and anthropogenic stressors, including climate change Significance StatementOur results address the important topic of adaptive evolution in marine species due to climate and environmental change induced due to anthropogenic perturbations. We present a new model system Chaetoceros muelleri which will help us address important evolutionary and long-term adaptation questions across evolutionary timescales. Our study reports (1) the revival of recent (0-80 years) to ancient (7200 years old) resting spores of Chaetoceros (2) the extraction of DNA and amplification of chloroplast and ribosomal genes from recent and ancient (~1300 years old) resting spores of Chaetoceros (3) Radiocarbon dating to determine age of sediments (4) Identification of species by reviving the resting spores (5) Baltic sea an excellent ecosystem to study long-term effects of environment on species adaptation