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Growth‐defense trade‐offs masked in unadmixed populations are revealed by hybridization
Author(s) -
Fetter Karl C.,
Nelson David M.,
Keller Stephen R.
Publication year - 2021
Publication title -
evolution
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.84
H-Index - 199
eISSN - 1558-5646
pISSN - 0014-3820
DOI - 10.1111/evo.14227
Subject(s) - biology , trait , trade off , selection (genetic algorithm) , plant disease resistance , adaptation (eye) , resistance (ecology) , natural selection , ecology , evolutionary biology , gene , genetics , artificial intelligence , neuroscience , computer science , programming language
Organisms are constantly challenged by pathogens and pests, which can drive the evolution of growth‐defense strategies. Plant stomata are essential for gas exchange during photosynthesis and conceptually lie at the intersection of the physiological demands of growth and exposure to foliar fungal pathogens. Generations of natural selection for locally adapted growth‐defense strategies can eliminate variation between traits, potentially masking trade‐offs and selection conflicts that may have existed in the past. Hybrid populations offer a unique opportunity to reset the clock on selection and to study potentially maladaptive trait variation before selection removes it. We study the interactions of growth, stomatal, ecopysiological, and disease resistance traits in poplars ( Populus ) after infection by the leaf rust Melampsora medusae . Phenotypes were measured in a common garden and genotyped at 227K SNPs. We isolate the effects of hybridization on trait variance, discover correlations between stomatal, ecophysiology, and disease resistance, examine trade‐offs and selection conflicts, and explore the evolution of growth‐defense strategies potentially mediated by selection for stomatal traits on the upper leaf surface. These results suggest an important role for stomata in determining growth‐defense strategies in organisms susceptible to foliar pathogens, and reinforces the contribution of hybridization studies toward our understanding of trait evolution.