Trade-offs and evolution of thermal adaptation in the Irish potato famine pathogen Phytophthora infestans.
Temperature is one of the most important environmental parameters with crucial impacts on nearly all biological processes. Due to anthropogenic activity, average air temperatures are expected to increase by a few degrees in coming decades, accompanied by an increased occurrence of extreme temperature events. Such global trends are likely to have various major impacts on human society through their influence on natural ecosystems, food production and biotic interactions, including diseases. In this study, we used a combination of statistical genetics, experimental evolution and common garden experiments to investigate the evolutionary potential for thermal adaptation in the potato late blight pathogen, Phytophthora infestans, and infer its likely response to changing temperatures. We found a trade-off associated with thermal adaptation to heterogeneous environments in P. infestans, with the degree of the trade-off peaking approximately at the pathogen's optimum growth temperature. A genetic trade-off in thermal adaptation was also evidenced by the negative association between a strain's growth rate and its thermal range for growth, and warm climates selecting for a low pathogen growth rate. We also found a mirror effect of phenotypic plasticity and genetic adaptation on growth rate. At below the optimum, phenotypic plasticity enhances pathogen's growth rate but nature selects for slower growing genotypes when temperature increases. At above the optimum, phenotypic plasticity reduces pathogen's growth rate but natural selection favours for faster growing genotypes when temperature increases further. We conclude from these findings that the growth rate of P. infestans will only be marginally affected by global warming.
Fujian Key Lab of Plant Virology, Institute of Plant Virology, Fujian Agriculture and Forestry University, Fuzhou, China.
Li-Na
LN
Yang
Fujian Key Lab of Plant Virology, Institute of Plant Virology, Fujian Agriculture and Forestry University, Fuzhou, China.
Wen
W
Zhu
Fujian Key Lab of Plant Virology, Institute of Plant Virology, Fujian Agriculture and Forestry University, Fuzhou, China.
E-Jiao
EJ
Wu
Fujian Key Lab of Plant Virology, Institute of Plant Virology, Fujian Agriculture and Forestry University, Fuzhou, China.
Ce
C
Yang
CSIRO Agriculture, PO Box 1600, Canberra, Australian Capital Territory, 2601, Australia.
Peter H
PH
Thrall
CSIRO Agriculture, PO Box 1600, Canberra, Australian Capital Territory, 2601, Australia.
Jeremy J
JJ
Burdon
Institute of Flowers and Vegetables, Chinese Academy of Agricultural Sciences, Beijing, 100081, China.
Li-Ping
LP
Jin
Fujian Key Lab of Plant Virology, Institute of Plant Virology, Fujian Agriculture and Forestry University, Fuzhou, China.
Li-Ping
LP
Shang
Key Lab for Biopesticide and Chemical Biology, Ministry of Education, Fujian Agriculture and Forestry University, Fuzhou, China.
Jiasui
J
Zhan
D000220:Adaptation, Biological / Q000235:genetics*; D005838:Genotype; D010641:Phenotype; D055750:Phytophthora infestans / Q000235:genetics*; D012641:Selection, Genetic; D011198:Solanum tuberosum / Q000382:microbiology*; D013696:Temperature
Phytophthora infestans; diversifying selection; genetic differentiation; pathogen evolution; phenotypic plasticity; thermal adaptation