Strategies of Phytophthora infestans adaptation to local UV radiation conditions

Abstract

Expected global changes in environmental conditions underline the need for a better understanding of genetic variation in ecological traits and their strategies of adaptation to the stresses. In this study, evolutionary mechanisms and processes of UV adaptation in plant pathogens were investigated by combining statistical genetics, physiological assays, and common garden experiment approaches in an assessment of the potato late blight pathogen, Phytophthora infestans, sampled from various geographic locations in China. We found spatial divergence caused by diversifying selection in UV tolerance among P. infestans populations. Local UV radiation was the driving force of selection as indicated by a positive correlation between UV tolerance in P. infestans populations and the altitude of collection sites. Plasticity accounted for 68% of population variation while heritability was negligible, suggesting temporary changes in gene expression and/or enzymatic activity play a more important role than permanent modification of gene structure in the evolution of UV adaptation. This adaptation strategy may explain the lack of fitness penalty observed in genotypes with higher UV tolerance.

Constraining Evolution of Alternaria alternata Resistance to a Demethylation Inhibitor (DMI) Fungicide Difenoconazole

“…Difenoconazole tolerance was measured by the relative intrinsic growth rate (RGR) of the pathogen isolates in the presence to the absence of difenoconazole (Zhan et al, 2006; Brunner et al, 2016; He et al, 2018). The percentile of difenoconazole tolerance in the combined population of the 215 A. alternata isolates was tabulated using a bin system as described previously (Qin et al, 2016; Wu et al, 2019). General linear model procedure was used to evaluate the contribution of population, fungicide concentration, pathogen genotype and genotype-concentration interaction to the phenotypic variance of difenoconazole tolerance and least significant difference (Kokalisburelle et al, 2013) was used to determine the spatial variation of difenoconazole tolerance in the A. alternata populations from different locations.…”

Rapid adaptation of the Irish potato famine pathogen Phytophthora infestans to changing temperature

“…These isolates were randomly collected from seven potato fields (three isolates from each field) located in Gansu, Guangxi, Guizhou, Ningxia, a subtropical climate, are the two provinces with the highest potential of developing a potato industry in coming decades . Detailed information on the collection, isolation, and molecular characterization of the pathogen isolates is provided in our previous publications (Qin et al, 2016;Wu, Wang, Shen, et al, 2019).…”

Temperature-Mediated Plasticity Regulates the Adaptation of Phytophthora infestans to Azoxystrobin Fungicide

“…SSR data of isolates collected from seven out of the nine field P. infestans populations (Ningxia, Gansu, Guizhou, Yunnan, Xiapu, Fuzhou, and Guangxi) were taken from earlier publications [22,39,40]; whereas, the genotypic data of the isolates for the remaining two populations (Inner Mongolia and Wuhan) were generated following the same protocols. In summary, mycelia (~100 mg) obtained from the individual isolates of P. infestans grown on rye B agar at 19 • C were composed and kept in 2 mL centrifuge tubes.…”

“…A total of 180 genetically distinct isolates, 20 from each of the nine P. infestans populations, were recovered from long storage and restored on rye B agar medium (50 g/L rye and 15 g/L agar). The azoxystrobin sensitivity of the 180 P. infestans isolates was evaluated at five experimental temperature schemes (13,16,19,22, and 25 • C) according to a common garden experiment [43,44]. Before setting the experiment, isolates were revived from long-term storage on culture media and grown on rye B agar at 19 • C for 8 days.…”

“…Consequently, neutral marker loci are expected to show a similar level of differentiation among populations, leading to the same level of Q ST in fungicide sensitivity and F ST in SSR marker loci. Q ST can be estimated by partitioning the total phenotypic variation to within-and among-population components in a way similar to the estimate of F ST in neutral genetic markers [20][21][22]. Many genetic and environmental factors including chemical property, pathogen biology, fungicide operational scheme, and climatic conditions can affect the types and intensity of natural selection and, therefore, influence the development of fungicide resistance in pathogens [23].…”