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Research article - Peer-reviewed, 2021

Multiple Mechanisms Drive the Evolutionary Adaptation of Phytophthora infestans Effector Avr1 to Host Resistance

Shen, Lin-Lin; Waheed, Abdul; Wang, Yan-Ping; Nkurikiyimfura, Oswald; Wang, Zong-Hua; Yang, Li-Na; Zhan, Jiasui

Abstract

Effectors, a group of small proteins secreted by pathogens, play a central role in antagonistic interactions between plant hosts and pathogens. The evolution of effector genes threatens plant disease management and sustainable food production, but population genetic analyses to understand evolutionary mechanisms of effector genes are limited compared to molecular and functional studies. Here we investigated the evolution of the Avr1 effector gene from 111 Phytophthora infestans isolates collected from six areas covering three potato cropping regions in China using a population genetic approach. High genetic variation of the effector gene resulted from diverse mechanisms including base substitution, pre-termination, intragenic recombination and diversifying selection. Nearly 80% of the 111 sequences had a point mutation in the 512th nucleotide (T512G), which generated a pre-termination stop codon truncating 38 amino acids in the C-terminal, suggesting that the C-terminal may not be essential to ecological and biological functions of P. infestans. A significant correlation between the frequency of Avr1 sequences with the pre-termination and annual mean temperature in the collection sites suggests that thermal heterogeneity might be one of contributors to the diversifying selection, although biological and biochemical mechanisms of the likely thermal adaptation are not known currently. Our results highlight the risk of rapid adaptation of P. infestans and possibly other pathogens as well to host resistance, and the application of eco-evolutionary principles is necessary for sustainable disease management in agricultural ecosystems.

Keywords

effector protein; mutation mechanisms; population genetics; natural selection; oomycete pathogen; intragenic recombination; local adaptation; sustainable disease management

Published in

Journal of Fungi
2021, Volume: 7, number: 10, article number: 789

    Associated SLU-program

    SLU Plant Protection Network

    Sustainable Development Goals

    SDG2 Zero hunger

    UKÄ Subject classification

    Agricultural Science
    Microbiology

    Publication identifier

    DOI: https://doi.org/10.3390/jof7100789

    Permanent link to this page (URI)

    https://res.slu.se/id/publ/115526