Data from: Adaptation to resistant hosts increases fitness on susceptible hosts in the plant parasitic nematode Globodera pallida

Trade-offs between virulence (defined as the ability to infect a resistant host) and life-history traits are of particular interest in plant pathogens for durable management of plant resistances. Adaptation to plant resistances (i.e., virulence acquisition) is indeed expected to be associated with a fitness cost on susceptible hosts. Here, we investigated whether life-history traits involved in the fitness of the potato cyst nematode Globodera pallida are affected in a virulent lineage compared to an avirulent one. Both lineages were obtained from the same natural population through experimental evolution on resistant and susceptible hosts, respectively. Unexpectedly, we found that virulent lineages were more fit than avirulent lineages on susceptible hosts: they produced bigger cysts, containing more larvae and hatching faster. We thus discuss possible reasons explaining why virulence did not spread into natural G. pallida populations.

毒力（virulence，定义为侵染抗病寄主的能力）与生活史性状之间的权衡关系，对于植物病原菌领域的植物抗病性持久化管理而言具有特殊研究价值。针对植物抗病性的适应性（即毒力获得），理论上确实会在感病寄主上产生适合度代价。本研究针对马铃薯胞囊线虫（Globodera pallida）展开探究，旨在明确相较于非毒力株系，毒力株系中与其适合度相关的生活史性状是否发生改变。两个株系均源自同一自然种群，分别通过在抗病寄主与感病寄主上的实验演化获得。令人意外的是，本研究发现毒力株系在感病寄主上的适合度反而高于非毒力株系：其产生的胞囊更大，内含幼虫数量更多，且孵化速度更快。据此，本文将探讨为何毒力未在自然种群的苍白球胞囊线虫（G. pallida）中扩散的潜在原因。