Evolutionary responses are required for tree populations to be able to track climate change. Results of 250 years of common garden experiments show that most forest trees have evolved local ...adaptation, as evidenced by the adaptive differentiation of populations in quantitative traits, reflecting environmental conditions of population origins. On the basis of the patterns of quantitative variation for 19 adaptation‐related traits studied in 59 tree species (mostly temperate and boreal species from the Northern hemisphere), we found that genetic differentiation between populations and clinal variation along environmental gradients were very common (respectively, 90% and 78% of cases). Thus, responding to climate change will likely require that the quantitative traits of populations again match their environments. We examine what kind of information is needed for evaluating the potential to respond, and what information is already available. We review the genetic models related to selection responses, and what is known currently about the genetic basis of the traits. We address special problems to be found at the range margins, and highlight the need for more modeling to understand specific issues at southern and northern margins. We need new common garden experiments for less known species. For extensively studied species, new experiments are needed outside the current ranges. Improving genomic information will allow better prediction of responses. Competitive and other interactions within species and interactions between species deserve more consideration. Despite the long generation times, the strong background in quantitative genetics and growing genomic resources make forest trees useful species for climate change research. The greatest adaptive response is expected when populations are large, have high genetic variability, selection is strong, and there is ecological opportunity for establishment of better adapted genotypes.
Nei's decomposition of total expected heterozygosity in subdivided populations into within‐ and between‐subpopulation components, HS and DST, respectively, is a classical tool in the conservation and ...management of genetic resources. Reviewing why this is not a decomposition into independent terms of within‐ and between‐subpopulation gene diversity, we illustrate how this approach can be misleading because it overemphasizes the within‐subpopulation component compared to Jost's nonadditive decomposition based on gene diversity indices. Using probabilistic partitioning of the total expected heterozygosity into independent within‐ and between‐subpopulation contributions, we show that the contribution of the within‐subpopulation expected heterozygosity to the total expected heterozygosity is not HS, as suggested by Nei's decomposition, but HS/s, with s being the number of subpopulations. Finally, we compare three possible approaches of decomposing total heterozygosity in subdivided populations (i.e., Nei's decomposition, Jost's approach, and probabilistic partitioning) with regard to independence between terms and sensitivity to unequal subpopulation sizes. For the conservation and management of genetic resources, we recommend using probabilistic partitioning and Jost's differentiation parameter rather than Nei's decomposition.
•Phenotypic variation in vigor and sensitivity is greater within than between stands.•Vigorous trees are more sensitive to drought stress.•Within-stand variances and correlations vary during stand ...development.•Phenotypic variation of sensitivity, but not vigor, is lower in stressful conditions.•Correlation between vigor and sensitivity decreases with higher soil water content.
Within-population variation in individual tree growth and response to climate has an impact on forest dynamics, resilience and adaptation to environmental change.
Combining dendrochronological analyses with a process-based ecophysiological model simulating drought stress at the stand scale, we studied the phenotypic variation of two growth-related traits within 22 pure stands of five contrasted tree species sampled in the RENECOFOR network over a wide range of ecological conditions. First, we computed the annual stress level from soil, climate and stand inventory data. Second, we computed individual sensitivity as the quantitative growth response to drought stress level and individual vigor as the capacity to grow in favorable years relative to an average stand-level growth model. We analyzed within-population variation and covariation of individual vigor and sensitivity, their temporal changes during stand development, as well as the effect of environmental conditions on population-level means, variances and correlation.
Our results show that within-population variances in sensitivity and vigor exceed the between-population variances for all species. The populations located in more stressful environments, i.e., low summer precipitation and extractable soil water, showed lower mean and variance of sensitivity, suggesting possible multiscale adaptation at the population level and within populations. None of the environmental factors considered had an effect on the average population vigor or on the within-population variance of vigor. We found a general positive correlation between individual growth sensitivity and vigor in 17 out of 22 populations, potentially revealing a growth performance trade-off. The correlation was more pronounced in low extractable soil water environments, which may be related to a need for stressful conditions to reveal the trade-off or be the consequence of adaptive processes, i.e., acclimation and selection.
If high within-population stand phenotypic variation in growth traits contributes to the resilience and adaptive capacity of forests to climate change, a trade-off could represent a constraint on selection. We provide genetic and environmental arguments supporting the hypothesis of a trade-off, then we highlight the importance of integrating it into the management process, especially during selective thinning, to avoid indirectly increasing population sensitivity by selecting the most vigorous trees.
•Agro-ecosystem service-based management requires a specific social–ecological framework.•An explicit, symmetric representation of ecological and social systems is required.•The agricultural ...landscape is the key level for multiservice management.•The design of collective management requires innovative stakeholder organizations and tools.
The sustainability of agro-ecosystems depends on their ability to deliver an entire package of multiple ecosystem services, rather than provisioning services alone. New social and ecological dimensions of agricultural management must be explored in agricultural landscapes, to foster this ability. We propose a social–ecological framework for the service-based management of agro-ecosystems, specified through an explicit and symmetric representation of the ecosystem and the social system, and the dynamic links between them. It highlights how management practices, with their multiple effects, could drive the provision of multiple services. Based on this framework, we have identified the design of collective multiservice management as a key research issue. It requires innovations in stakeholder organizations and tools to foster synergy between ecosystem functioning and social dynamics, given the complexity and uncertainties of ecological systems.
Lactococci are noninvasive bacteria frequently used as protein delivery vectors and, more recently, as in vitro and in vivo DNA delivery vehicles. We previously showed that a functional eukaryotic ...enhanced green fluorescent protein (eGFP) expression plasmid vector was delivered in epithelial cells by Lactococcus lactis producing Listeria monocytogenes internalin A (L. lactis InlA⁺), but this strategy is limited in vivo to transgenic mice and guinea pigs. In this study, we compare the internalization ability of L. lactis InlA⁺ and L. lactis producing either the fibronectin-binding protein A of Staphylococcus aureus (L. lactis FnBPA⁺) or its fibronectin binding domains C and D (L. lactis CD⁺). L. lactis FnBPA⁺ and L. lactis InlA⁺ showed comparable internalization rates in Caco-2 cells, while the internalization rate observed with L. lactis CD⁺ was lower. As visualized by conventional and confocal fluorescence microscopy, large clusters of L. lactis FnBPA⁺, L. lactis CD⁺, and L. lactis InlA⁺ were present in the cytoplasm of Caco-2 cells after internalization. Moreover, the internalization rates of Lactobacillus acidophilus NCFM and of an NCFM mutant strain with the gene coding for the fibronectin-binding protein (fbpA) inactivated were also evaluated in Caco-2 cells. Similar low internalization rates were observed for both wild-type L. acidophilus NCFM and the fbpA mutant, suggesting that commensal fibronectin binding proteins have a role in adhesion but not in invasion. L. lactis FnBPA⁺, L. lactis CD⁺, and L. lactis InlA⁺ were then used to deliver a eukaryotic eGFP expression plasmid in Caco-2 cells: flow cytometry analysis showed that the highest percentage of green fluorescent Caco-2 cells was observed after coculture with either L. lactis FnBPA⁺ or L. lactis InlA⁺. Analysis of the in vivo efficiency of these invasive recombinant strains is currently in progress to validate their potential as DNA vaccine delivery vehicles.
Plants synthesize a diversity of volatile molecules that are important for reproduction and defense, serve as practical products for humans, and influence atmospheric chemistry and climate. Despite ...progress in deciphering plant volatile biosynthesis, their release from the cell has been poorly understood. The default assumption has been that volatiles passively diffuse out of cells. By characterization of a Petunia hybrida adenosine triphosphate–binding cassette (ABC) transporter, PhABCG1, we demonstrate that passage of volatiles across the plasma membrane relies on active transport. PhABCG1 down-regulation by RNA interference results in decreased emission of volatiles, which accumulate to toxic levels in the plasma membrane. This study provides direct proof of a biologically mediated mechanism of volatile emission.
1. Rapid climate change both imposes strong selective pressures on natural populations — potentially reducing their growth rate and causing genetic evolution — and affects the physiology and ...development of individual organisms. Understanding and predicting the fates of populations under global change, including extinctions and geographical range shifts, requires analysing the interplay of these processes, which has long been a grey area in evolutionary biology. 2. We review recent theory on the interaction of phenotypic plasticity, genetic evolution and demography in environments that change in time or space. We then discuss the main limitations of the models and the difficulties in testing theoretical predictions in the wild, notably regarding changes in phenotypic selection, the evolution of (co)variances of reaction norm parameters, and transient dynamics. 3. We use two landmark examples of physiological responses to climate change —trees facing drier climate and extreme temperatures, and marine phytoplankton under rising CO 2 — to highlight relatively neglected questions and indicate the theoretical and empirical challenges that they raise. These examples illustrate notably that age-specific patterns of plasticity and selection on the one hand, and changes in community interactions and functioning on the other hand, need to be further investigated theoretically and empirically for a better understanding of evolutionary demographic responses to climate change in the wild.
Genetic diversity parameters are used by plant breeders to develop efficient genetic resources sampling and conservation strategies. Extending previous developments on the use of ANOVA on allele ...frequencies in a fixed set of populations, we show that this approach allows unbiased estimation of diversity parameters, including Nei’s diversity parameters,
H
S
, the within-population diversity;
D
ST
, the between-population differentiation;
H
T
, the total gene diversity; and other related parameters well suited for guiding conservation decisions. We consider two cases: selfing plants and outcrossing plants. For outcrossing plants, this approach also allows the estimation of the average frequency of heterozygotes (
H
0
) and average departure of populations from a random mating equilibrium. These unbiased ANOVA estimators correspond to those derived by Nei and Chesser (Ann Hum Genet 47:253–259, 1983) by using properties related to the multinomial sampling of genotypes. With an equal number of individuals sampled per population, we first developed analyses of variation for each allele at one locus. Then, considering the whole set of alleles, we show the correspondence between the sum of the variances in allele frequencies over the alleles and Nei’s within- and between-population diversities. Considering large populations leads to Nei’s relationship,
H
T
=
H
S
+
D
ST
, which is a decomposition of the total variance in allele frequencies into within- and between-population variance components, variance meaning the sum of the variances of each allele over the whole set of alleles. Finally, we use theoretical results of the ANOVA approach to consider a genetic resources conservation design with only one individual per population, which allows Nei’s total gene diversity to be maintained.
A transnational network of genetic conservation units for forest trees was recently documented in Europe aiming at the conservation of evolutionary processes and the adaptive potential of natural or ...man‐made tree populations. In this study, we quantified the vulnerability of individual conservation units and the whole network to climate change using climate favourability models and the estimated velocity of climate change. Compared to the overall climate niche of the analysed target species populations at the warm and dry end of the species niche are underrepresented in the network. However, by 2100, target species in 33–65 % of conservation units, mostly located in southern Europe, will be at the limit or outside the species' current climatic niche as demonstrated by favourabilities below required model sensitivities of 95%. The highest average decrease in favourabilities throughout the network can be expected for coniferous trees although they are mainly occurring within units in mountainous landscapes for which we estimated lower velocities of change. Generally, the species‐specific estimates of favourabilities showed only low correlations to the velocity of climate change in individual units, indicating that both vulnerability measures should be considered for climate risk analysis. The variation in favourabilities among target species within the same conservation units is expected to increase with climate change and will likely require a prioritization among co‐occurring species. The present results suggest that there is a strong need to intensify monitoring efforts and to develop additional conservation measures for populations in the most vulnerable units. Also, our results call for continued transnational actions for genetic conservation of European forest trees, including the establishment of dynamic conservation populations outside the current species distribution ranges within European assisted migration schemes.
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