scholarly journals Genomic and common garden approaches yield complementary results for quantifying environmental drivers of local adaptation in rubber rabbitbrush, a foundational Great Basin shrub

2021 ◽  
Author(s):  
Trevor M. Faske ◽  
Alison C. Agneray ◽  
Joshua P. Jahner ◽  
Lana M. Sheta ◽  
Elizabeth A. Leger ◽  
...  
2021 ◽  
Author(s):  
Trevor M Faske ◽  
Alison C Agneray ◽  
Joshua P Jahner ◽  
Lana M Sheta ◽  
Elizabeth A Leger ◽  
...  

The spatial structure of genomic and phenotypic variation across populations reflects historical and demographic processes as well as evolution via natural selection. Characterizing such variation can provide an important perspective for understanding the evolutionary consequences of changing climate and for guiding ecological restoration. While evidence for local adaptation has been traditionally evaluated using phenotypic data, modern methods for generating and analyzing landscape genomic data can directly quantify local adaptation by associating allelic variation with environmental variation. Here, we analyze both genomic and phenotypic variation of rubber rabbitbrush (Ericameria nauseosa), a foundational shrub species of western North America. To quantify landscape genomic structure and provide perspective on patterns of local adaptation, we generated reduced representation sequencing data for 17 wild populations (222 individuals; 38,615 loci) spanning a range of environmental conditions. Population genetic analyses illustrated pronounced landscape genomic structure jointly shaped by geography and environment. Genetic-environment association (GEA) analyses using both redundancy analysis (RDA) and a machine-learning approach (Gradient Forest) indicated environmental variables (precipitation seasonality, slope, aspect, elevation, and annual precipitation) influenced spatial genomic structure, and were correlated with allele frequency shifts indicative of local adaptation at a consistent set of genomic regions. We compared our GEA based inference of local adaptation with phenotypic data collected by growing seeds from each population in a greenhouse common garden. Population differentiation in seed weight, emergence, and seedling traits was associated with environmental variables (e.g., precipitation seasonality) that were also implicated in GEA analyses, suggesting complementary conclusions about the drivers of local adaptation across different methods and data sources. Our results provide a baseline understanding of spatial genomic structure for E. nauseosa across the western Great Basin and illustrate the utility of GEA analyses for detecting the environmental causes and genetic signatures of local adaptation in a widely distributed plant species of restoration significance.


2018 ◽  
Author(s):  
Sara Marin ◽  
Juliette Archambeau ◽  
Vincent Bonhomme ◽  
Mylène Lascoste ◽  
Benoit Pujol

ABSTRACTPhenotypic differentiation among natural populations can be explained by natural selection or by neutral processes such as drift. There are many examples in the literature where comparing the effects of these processes on multiple populations has allowed the detection of local adaptation. However, these studies rarely identify the agents of selection. Whether population adaptive divergence is caused by local features of the environment, or by the environmental demand emerging at a more global scale, for example along altitudinal gradients, is a question that remains poorly investigated. Here, we measured neutral genetic (FST) and quantitative genetic (QST) differentiation among 13 populations of snapdragon plants (Antirrhinum majus) in a common garden experiment. We found low but significant genetic differentiation at putatively neutral markers, which supports the hypothesis of either ongoing pervasive homogenisation via gene flow between diverged populations or reproductive isolation between disconnected populations. Our results also support the hypothesis of local adaptation involving phenological, morphological, reproductive and functional traits. They also showed that phenotypic differentiation increased with altitude for traits reflecting the reproduction and the phenology of plants, thereby confirming the role of such traits in their adaptation to environmental differences associated with altitude. Our approach allowed us to identify candidate traits for the adaptation to climate change in snapdragon plants. Our findings imply that environmental conditions changing with altitude, such as the climatic envelope, influenced the adaptation of multiple populations of snapdragon plants on the top of their adaptation to local environmental features. They also have implications for the study of adaptive evolution in structured populations because they highlight the need to disentangle the adaptation of plant populations to climate envelopes and altitude from the confounding effects of selective pressures acting specifically at the local scale of a population.


2011 ◽  
Vol 4 (4) ◽  
pp. 209-220 ◽  
Author(s):  
S. K. Ebeling ◽  
J. Stocklin ◽  
I. Hensen ◽  
H. Auge

2021 ◽  
Author(s):  
Irene Cordero ◽  
María Dolores Jiménez ◽  
Juan Antonio Delgado ◽  
Luis Balaguer ◽  
José J Pueyo ◽  
...  

Abstract Photoprotection is a plant functional mechanism to prevent photooxidative damage by excess light. This is most important when carbon assimilation is limited by drought, and as such, it entails a trade-off between carbon assimilation vs stress avoidance. The ecological adaptation of plants to local water availability can lead to different photoprotective strategies. To test this, we used different provenances of Caesalpinia spinosa (Mol.) Kuntze (commonly known as ‘tara’) along a precipitation gradient. Tara is a Neotropical legume tree with high ecological and commercial value, found in dry tropical forests, which are increasingly threatened by climate change. Morphological and physiological responses of tara provenances were analysed under three different treatments of drought and leaflet immobilization, i.e., light stress, in a common garden greenhouse experiment. Tara quickly responded to drought by reducing stomatal conductance, evapotranspiration, photochemical efficiency, carbon assimilation and growth, while increasing structural and chemical photoprotection (leaflet angle and pigments for thermal dissipation). Leaflet closure was an efficient photoprotection strategy with overall physiological benefits for seedlings as it diminished the evaporative demand and avoided photodamage, but also entailed costs by reducing net carbon assimilation opportunities. These responses depended on seed origin, with seedlings from the most xeric locations showing the highest dehydration tolerance, suggesting local adaptation and highlighting the value of different strategies under distinct environments. This plasticity in its response to environmental stress allows tara to thrive in locations with contrasting water availability. Our findings increase the understanding of the factors controlling the functional ecology of tara in response to drought, which can be leveraged to improve forecasts of changes in its distribution range, and for planning restoration projects with this keystone tree species.


2021 ◽  
Vol 288 (1955) ◽  
pp. 20210741
Author(s):  
Andrew R. Villeneuve ◽  
Lisa M. Komoroske ◽  
Brian S. Cheng

Populations within species often exhibit variation in traits that reflect local adaptation and further shape existing adaptive potential for species to respond to climate change. However, our mechanistic understanding of how the environment shapes trait variation remains poor. Here, we used common garden experiments to quantify thermal performance in eight populations of the marine snail Urosalpinx cinerea across thermal gradients on the Atlantic and the Pacific coasts of North America. We then evaluated the relationship between thermal performance and environmental metrics derived from time-series data. Our results reveal a novel pattern of ‘mixed’ trait performance adaptation, where thermal optima were positively correlated with spawning temperature (cogradient variation), while maximum trait performance was negatively correlated with season length (countergradient variation). This counterintuitive pattern probably arises because of phenological shifts in the spawning season, whereby ‘cold’ populations delay spawning until later in the year when temperatures are warmer compared to ‘warm’ populations that spawn earlier in the year when temperatures are cooler. Our results show that variation in thermal performance can be shaped by multiple facets of the environment and are linked to organismal phenology and natural history. Understanding the impacts of climate change on organisms, therefore, requires the knowledge of how climate change will alter different aspects of the thermal environment.


2016 ◽  
Author(s):  
Jesse R. Lasky ◽  
Brenna R. Forester ◽  
Matthew Reimherr

Local adaptation is often studied via 1) multiple common garden experiments comparing performance of genotypes in different environments and 2) sequencing genotypes from multiple locations and characterizing geographic patterns in allele frequency. Both approaches aim to characterize the same pattern (local adaptation), yet the complementary information from each has not yet been coherently integrated. Here, we develop a genome-wide association model of genotype interactions with continuous environmental gradients (G×E), i.e. reaction norms. We present an approach to impute relative fitness, allowing us to coherently synthesize evidence from common garden and genome-environment associations. Our approach identifies loci exhibiting environmental clines where alleles are associated with higher fitness in home environments. Simulations show our approach can increase power to detect loci causing local adaptation. In a case study on Arabidopsis thaliana, most identified SNPs exhibited home allele advantage and fitness tradeoffs along climate gradients, suggesting selective gradients can maintain allelic clines. SNPs exhibiting G×E associations with fitness were enriched in genic regions, putative partial selective sweeps, and associations with an adaptive phenotype (flowering time plasticity). We discuss extensions for situations where only adaptive phenotypes other than fitness are available. Many types of data may point toward the loci underlying G×E and local adaptation; coherent models of diverse data provide a principled basis for synthesis.


2021 ◽  
Author(s):  
Zhi Wang ◽  
Xiao-Qi Jiang ◽  
Xing-xing Cai ◽  
Qi-Yu Xia ◽  
Bao-Rong Lu

Abstract Background: Temperatures and photoperiods can profoundly affect plant growth and development and play vital roles in the local adaptation of plant species. Weedy rice (Oryza sativa f. spontanea) is a conspecific weed of cultivated rice, and it was found in the same rice fields (sympatry) of early and late rice-cultivation seasons in Leizhou, Guangdong Province of China. Generally, the phenological conditions, such as temperature and photoperiod, are different in the two seasons. Therefore, the early- and late-season weedy rice populations in the same rice fields provide a perfect system for estimating sympatric divergence in plant species. The previous study had demonstrated considerable genetic divergence between the early- and late-season weedy rice populations. Here, we designed in situ common garden experiments to estimate the phenotypical differences between the two-season weedy rice populations and disclose the local adaptation in weedy rice populations associated with their ambient temperature and photoperiod.Results: Distinct air temperature and day length variation patterns were recognized between the early and late rice-cultivation seasons, based on the 10-year historical climate data. More stressful conditions, indicated by low air temperature and long day length, were found for weedy rice growth in the early seasons. Noticeably, significant differences in plant heights, the number of tillers, flowering time, and reproductive traits were detected between the two-season weedy rice populations according to the early-season common garden experiment. The early-season populations showed evident higher plant heights, more tillers, and earlier flowering time than the late-season populations. However, such differences were not detected in the late-season common garden experiment. In addition, evident local adaptation represented by the traits such as plant heights, flowering time, and reproductive traits was only detected in the early-season weedy rice populations. The principal component analysis also showed clear population clusters between the two-season populations using the phenotypical data.Conclusions: This study provided clear evidence of phenotypic differentiation between the sympatric early- and late-season weedy rice populations, probably associated with the local adaptation to their ambient temperature and photoperiod. Our findings also have potential roles in facilitating the design of strategies for effective weedy rice control practices.


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