lara romero congreso_restauracion_utpl_2016

El rol de las poblaciones marginales en el manejo y

restauración de poblaciones silvestre en un clima cambiante

Lara-Romero C, Morente-López J, García-Fernández

A, Rubio ML, Iriondo JM

Rey Juan Carlos UniversityMadrid

Introduction Aims In situ experiments Transcriptomic experiment Conclusions

Evolutionary Resilience and Assisted Evolution in restoration practices

• Ability of populations to persist in their current state.• Undergo evolutionary adaptation in response to changing environmental conditions

Both concepts are a way of conserving evolutionary

potential of speciesand populations

The use of genetically resilient individuals can restore or maintain key ecosystem attributes and processes

Mascarelli, A. 2014. NatureSgrò, C. 2010. Evolutionary Applications

Marginal populations:• grow under suboptimal environmental conditions• great fluctuations and high probability of extinction

Soulé (1973)


• Genetically impoverished populations

• Inbreeding depression• Maladaptation

• Not necessarilydepauperate for variationin ecologically relevanttraits.

• Locally adapted

Marginal populations:• grow under suboptimal environmental conditions• great fluctuations and high probability of extinction

Soulé (1973)

?

Kawecki, T. J. 2008. Annu. Rev. Ecol. Evol. Syst. Soulé M. 1973. Annu. Rev. Ecol. Sys.

Lande R. 1994. EvolutionWhitlock MC. 2003. Genetics

Lande (1994), Whitlock (2003) Kawecki (2008)


Mediterranean alpine environments: highly vulnerable to global warming

Marginal populations

Central populations

temperature rainfall


Nogués-Brano et al 2007. Global Environmental ChangePaulí et al 2012. Science

Experimental gene flow between populations:– assessment of inbreeding depression and geneflow of

adaptive/maladaptive value

– management tool to assist marginal populations


Central populations

Holt RD, Gomulkiewicz R. 1997. Am NatKirkpatrick M, Barton NH. 1997. Am Nat






Central populations

central – marginal geneflow:• Genetic diversity (Holt & Gomulkiewicz, 1997)• Maladaptive alleles or gene combinations

(Kirkpatrick & Barton, 1997)

Holt RD, Gomulkiewicz R. 1997. Am NatKirkpatrick M, Barton NH. 1997. Am Nat






Central populations

marginal-marginal geneflow• Genetic diversity & adaptive alleles or gene combinations (Sexton et al. 2011)

Sexton JP, Strauss SY, Rice KJ. 2011. PNAS


Aim: • To assess whether marginal populations at the lowest elevation of

Mediterranean alpine plants are locally adapted/maladapted to the environmental conditions that will prevail with global warming


• Circum-mediterranean alpine chamaephyte

• Central System at the lowest latitude of the distibution range:

– Sierra de Béjar

– Sierra de Gredos

– Sierra de Guadarrama

• Elevation range: 1900 – 2500 m

Silene ciliata Pourret


• Central population

• Marginal populations

Central vs. marginal populations

Giménez-Benavides, L., Albert, M.J., Iriondo, J.M. & Escudero, A. Ecography (2011)

GuadarramaGredosBéjar


(Giménez-Benavides et al. 2011)

Seeds obtained in common garden conditions from artificial crossings simulatingdifferent types of geneflow

Gene flow simulation experiment

Central population fromsame mountainrange

Marginal population

Marginal population fromsame mountainrange

X 6 marginal populations

C1

C2

C3


Sowing experiment at the locations of the 6 marginal populations

(mother plant x type of cross x block x pop. = 24 000 seeds)



Central populations

C1C2

C3

x 2 marginal populationsx 3 mountains


Sexton JP, Strauss SY, Rice KJ. 2011. PNAS

Evidence of adaptive geneflow between marginal populations (C1 < C2):

Mimulus laciniatus (Sexton et al., 2011)


Central populations

C1C2

C3



Survival

Treatment

Su

rviv

al p

rop

ort

ion

F1 F2 F3

0.0

0.2

0.4

Seedling survival

Gene flow

Surv

ival

(%

)

0

60

40

No evidence of maladaptive gene flow from central populations (C1 ≤ C3)

Little evidence of inbreeding load (C1 < C2; C1 ≤ C3)


Central populations

C1C2

C3



Survival

Treatment

Su

rviv

al p

rop

ort

ion

F1 F2 F3

0.0

0.2

0.4

Seedling survival

Gene flow

Surv

ival

(%

)

0

60

40

García-Fernández A, Iriondo JM & Escudero A. 2012 Oikos

Reciprocal sowing experiments among central and marginal populations to test for evidence of local adaptation

(mother plant x type of cross x block x pop. = 7 250 seeds)

Reciprocal sowing experiments


Central populations


x 3 mountains

On-going research but…



Central populations


…previous reciprocal sowing experiments found evidence of local adaptation in seedling survival and growth in central and marginal populations


Giménez-Benavides L, Escudero A & Iriondo JM 2007. Annals of Botany


Central populations



Transcriptome analyses

Massive sequencing of the transcriptome of seedlings from central and marginal populationsgrown under controlled conditions.

Identification of polymorphisms and differential expression levels in candidate genes betweenseedlings from central and marginal populations.

T G T C G G T C TT G T C G G T C T

T G T C A G T C TT G T C A G T C T

Single Nucleotide Polymorphism (SNP)

Central

Marginal

Differential expression


Transcriptome analyses

Massive sequencing of the transcriptome of seedlings from central and marginal populationsgrown under controlled conditions.

Identification of polymorphisms and differential expression levels in candidate genes betweenseedlings from central and marginal populations.

Functional annotation & Enrichment analysis

We expect to find some candidate genes codifying proteins involved in responses toabiotic stimulus, particularly drought stress.

T G T C G G T C TT G T C G G T C T

T G T C A G T C TT G T C A G T C T

Single Nucleotide Polymorphism (SNP)

Central

Marginal


RPKM (Reads per kilobase per million mapped reads)


Comparison of expression levels (RPKM) between central and marginal populations

129 contigs differentially expressed

GO term & Enrichment analysis

• 114 contigs annotated (i.e., protein-coding genes)

• Response to extracellular stimulus (n=9) & external stimulus (n=19) overrepresented

Central

Marginal


Differential expression analysis

Contig: pieces of DNA representing overlapping regions of a particular chromosome


6 genes overlapped among three approaches

GO TERM: response to stress & metabolic process

163 genes overlapped among two approaches

• 143 annotated genes

• Enrichment analysis (before FDR correction)

- Response to abiotic stimulus (n = 53)- Response to stress (n = 59)- Several additional terms related to metabolic processes and response to stimulus

SNP calling & outlier detection

Dispersal param. Allele freq.

AFD

336 606

275

20

131246

Muller et al 2010 Evolutionary Applications, Turner et al 2010 Nature, Stölting et al 2015 New Phytologist

[1] Contingency table and Pearson’s Chi-square test (X2)

[2] Dispersal parameter (m, Muller et al 2010 Evolutionary Applications)

[3] Allelic frequency differentials (AFDs)

Alternative strategies for selection of outlier SNPs

1. Adaptive geneflow between marginal populations at the seedling stage.

2. No maladaptive geneflow between central and marginal populations at the seedling stage.

3. Some evidence of inbreeding load in marginal populations.

4. Genes involved in stress responses might play an important role in the adaptation to marginal environments.

5. Marginal populations might be of high importance to assistcentral populations as they can provide alleles or genecombinations adapted to the environmental conditions that willprevail with global warming.


Conclusions

Introduction Past studies Current research Future prospectsAcknowledgements:

• C. Diaz, G. Escribano, S. Prieto, P. Tabares, S. Eleazar, L. Cano, L. Martinez, S. Fior, M. Roumet

• Sierra de Guadarrama National Park• Sierra de Gredos Regional Park• Sierras de Béjar y Francia Biosphere Reserve

• AdAptA Project CGL2012-33528, Spanish National R&D&I Plan

• ESF networking programmaConGenOmics

Funding: