TY - JOUR
T1 - The genetic architecture of plant defense trade-offs in a common monkeyflower
AU - Kooyers, Nicholas J.
AU - Donofrio, Abigail
AU - Blackman, Benjamin K.
AU - Holeski, Liza M.
N1 - Funding Information:
This work was supported by the University of Louisiana, Lafayette, an Ecological, Evolutionary, and Conservation Genomics grant from the American Genetics Association to N.J.K., a New Research Grant from University of South Florida to N.J.K., a National Science Foundation grant (IOS-1558035) to N.J.K. and B.K.B., and a National Science Foundation grant (OIA-1920858) to N.J.K., and a Faculty Grants Program award from Northern Arizona University (L.M.H.).
Publisher Copyright:
© The American Genetic Association 2020. All rights reserved.
PY - 2020/6/1
Y1 - 2020/6/1
N2 - Determining how adaptive combinations of traits arose requires understanding the prevalence and scope of genetic constraints. Frequently observed phenotypic correlations between plant growth, defenses, and/or reproductive timing have led researchers to suggest that pleiotropy or strong genetic linkage between variants affecting independent traits is pervasive. Alternatively, these correlations could arise via independent mutations in different genes for each trait and extensive correlational selection. Here we evaluate these alternatives by conducting a quantitative trait loci (QTL) mapping experiment involving a cross between 2 populations of common monkeyflower (Mimulus guttatus) that differ in growth rate as well as total concentration and arsenal composition of plant defense compounds, phenylpropanoid glycosides (PPGs). We find no evidence that pleiotropy underlies correlations between defense and growth rate. However, there is a strong genetic correlation between levels of total PPGs and flowering time that is largely attributable to a single shared QTL.While this result suggests a role for pleiotropy/close linkage, several other QTLs also contribute to variation in total PPGs. Additionally, divergent PPG arsenals are influenced by a number of smaller-effect QTLs that each underlie variation in 1 or 2 PPGs.This result indicates that chemical defense arsenals can be finely adapted to biotic environments despite sharing a common biochemical precursor. Together, our results show correlations between defense and life-history traits are influenced by pleiotropy or genetic linkage, but genetic constraints may have limited impact on future evolutionary responses, as a substantial proportion of variation in each trait is controlled by independent loci.
AB - Determining how adaptive combinations of traits arose requires understanding the prevalence and scope of genetic constraints. Frequently observed phenotypic correlations between plant growth, defenses, and/or reproductive timing have led researchers to suggest that pleiotropy or strong genetic linkage between variants affecting independent traits is pervasive. Alternatively, these correlations could arise via independent mutations in different genes for each trait and extensive correlational selection. Here we evaluate these alternatives by conducting a quantitative trait loci (QTL) mapping experiment involving a cross between 2 populations of common monkeyflower (Mimulus guttatus) that differ in growth rate as well as total concentration and arsenal composition of plant defense compounds, phenylpropanoid glycosides (PPGs). We find no evidence that pleiotropy underlies correlations between defense and growth rate. However, there is a strong genetic correlation between levels of total PPGs and flowering time that is largely attributable to a single shared QTL.While this result suggests a role for pleiotropy/close linkage, several other QTLs also contribute to variation in total PPGs. Additionally, divergent PPG arsenals are influenced by a number of smaller-effect QTLs that each underlie variation in 1 or 2 PPGs.This result indicates that chemical defense arsenals can be finely adapted to biotic environments despite sharing a common biochemical precursor. Together, our results show correlations between defense and life-history traits are influenced by pleiotropy or genetic linkage, but genetic constraints may have limited impact on future evolutionary responses, as a substantial proportion of variation in each trait is controlled by independent loci.
KW - Erythranthe guttata
KW - Flowering time
KW - Mimulus guttatus (common yellow monkeyflower)
KW - Phenylpropanoid glycosides
KW - Plant functional strategies
KW - Quantitative trait loci (QTL)
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U2 - 10.1093/jhered/esaa015
DO - 10.1093/jhered/esaa015
M3 - Article
C2 - 32479597
AN - SCOPUS:85089427091
SN - 0022-1503
VL - 111
SP - 333
EP - 345
JO - Journal of Heredity
JF - Journal of Heredity
IS - 4
ER -