Comparative analyses of fungicide sensitivity and SSR marker variations indicate a low risk of developing azoxystrobin resistance in Phytophthora infestans

Self Cite

The spread of antimicrobial resistance and global change in air temperature represent two major phenomena that are exerting a disastrous impact on natural and social issues but investigation of the interaction between these phenomena in an evolutionary context is limited. In this study, a statistical genetic approach was used to investigate the evolution of antimicrobial resistance in agricultural ecosystem and its association with local air temperature, precipitation, and UV radiation. We found no resistance to mancozeb, a nonspecific fungicide widely used in agriculture for more than half a century, in 215 Alternaria alternata isolates sampled from geographic locations along a climatic gradient and cropping system representing diverse ecotypes in China, consistent with low resistance risk in many nonspecific fungicides. Genetic variance accounts for ~35% of phenotypic variation, while genotype–environment interaction is negligible, suggesting that heritability plays a more important role in the evolution of resistance to mancozeb in plant pathogens than phenotypic plasticity. We also found that tolerance to mancozeb in agricultural ecosystem is under constraining selection and significantly associated with local air temperature, possibly resulting from a pleiotropic effect of resistance with thermal and other ecological adaptations. The implication of these results for fungicide and other antimicrobial management in the context of global warming is discussed.

Section: Discussionsupporting

confidence: 74%

Q_{ST} = \frac{{normalδ}_{AP}^{2} + {normalδ}_{P \times E}^{2} / n}{{normalδ}_{AP}^{2} + {normalδ}_{P \times E}^{2} / n + {normalδ}_{WP}^{2}}

where

δ_{AP}^{2}

δ_{WP}^{2}

δ_{normalP \times normalE}^{2}

Section: Methodsmentioning

confidence: 99%

Slow and temperature‐mediated pathogen adaptation to a nonspecific fungicide in agricultural ecosystem

Zhu

et al. 2017

Self Cite

“…Genetic diversity of Avr3a gene was found to be high in the current study, and nucleotide diversity (Table 1) was positively correlated ( r = .72, p = .10, data not shown) to SSR diversity (Qin et al., 2016). More than 50 nucleotide haplotypes were detected in 96 sequences, and the combined nucleotide diversity was 0.017 (Table 1).…”

Section: Discussionmentioning

confidence: 99%

Evidence for intragenic recombination and selective sweep in an effector gene of Phytophthora infestans

Yang

Ouyang

Fang

et al. 2018

Self Cite

Effectors, a group of small proteins secreted by pathogens, play a critical role in the antagonistic interaction between plant hosts and pathogens through their dual functions in regulating host immune systems and pathogen infection capability. In this study, evolution in effector genes was investigated through population genetic analysis of Avr3a sequences generated from 96 Phytophthora infestans isolates collected from six locations representing a range of thermal variation and cropping systems in China. We found high genetic variation in the Avr3a gene resulting from diverse mechanisms extending beyond point mutations, frameshift, and defeated start and stop codons to intragenic recombination. A total of 51 nucleotide haplotypes encoding 38 amino acid isoforms were detected in the 96 full sequences with nucleotide diversity in the pathogen populations ranging from 0.007 to 0.023 (mean = 0.017). Although haplotype and nucleotide diversity were high, the effector gene was dominated by only three haplotypes. Evidence for a selective sweep was provided by (i) the population genetic differentiation (G ST) of haplotypes being lower than the population differentiation (F ST ) of SSR marker loci; and (ii) negative values of Tajima's D and Fu's FS. Annual mean temperature in the collection sites was negatively correlated with the frequency of the virulent form (Avr3aEM), indicating Avr3a may be regulated by temperature. These results suggest that elevated air temperature due to global warming may hamper the development of pathogenicity traits in P. infestans and further study under confined thermal regimes may be required to confirm the hypothesis.

“…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).…”

Section: Parental Isolates For the Temperature Acclimation Experimentsmentioning

confidence: 99%

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

Wang

Lurwanu

et al. 2019

Self Cite

Temperature plays a multidimensional role in host–pathogen interactions. As an important element of climate change, elevated world temperature resulting from global warming presents new challenges to sustainable disease management. Knowledge of pathogen adaptation to global warming is needed to predict future disease epidemiology and formulate mitigating strategies. In this study, 21 Phytophthora infestans isolates originating from seven thermal environments were acclimated for 200 days under stepwise increase or decrease of experimental temperatures and evolutionary responses of the isolates to the thermal changes were evaluated. We found temperature acclimation significantly increased the fitness and genetic adaptation of P. infestans isolates at both low and high temperatures. Low‐temperature acclimation enforced the countergradient adaptation of the pathogen to its past selection and enhanced the positive association between the pathogen's intrinsic growth rate and aggressiveness. At high temperatures, we found that pathogen growth collapsed near the maximum temperature for growth, suggesting a thermal niche boundary may exist in the evolutionary adaptation of P. infestans. These results indicate that pathogens can quickly adapt to temperature shifts in global warming. If this is associated with environmental conditions favoring pathogen spread, it will threaten future food security and human health and require the establishment of mitigating actions.