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Abstract：
Studies of infection by Phytophthora infestans-the causal agent of potato late blight-in wild species can provide novel insights into plant defense responses, and indicate how wild plants might be influenced by recurrent epidemics in agricultural fields. In the present study, our aim was to investigate if different clones of Solanum dulcamara (a relative of potato) collected in the wild differ in resistance and tolerance to infection by a common European isolate of P. infestans. We performed infection experiments with six S. dulcamara genotypes (clones) both in the laboratory and in the field and measured the degree of infection and plant performance traits. In the laboratory, the six evaluated genotypes varied from resistant to susceptible, as measured by degree of infection 20 days post infection. Two of the four genotypes susceptible to infection showed a quadratic (concave downward) relationship between the degree of infection and shoot length, with maximum shoot length at intermediate values of infection. This result suggests overcompensation, that is, an increase in growth in infected individuals. The number of leaves decreased with increasing degree of infection, but at different rates in the four susceptible genotypes, indicating genetic variation for tolerance. In the field, the inoculated genotypes did not show any disease symptoms, but plant biomass at the end of the growing season was higher for inoculated plants than for controls, in-line with the overcompensation detected in the laboratory. We conclude that in S. dulcamara there are indications of genetic variation for both resistance and tolerance to P. infestans infection. Moreover, some genotypes displayed overcompensation. Learning about plant tolerance and overcompensation to infection by pathogens can help broaden our understanding of plant defense in natural populations and help develop more sustainable plant protection strategies for economically important crop diseases.
摘要：
在野生物种中，马铃薯晚疫病的致病因子致病疫霉的感染研究可以为植物防御反应提供新的见解，并指出野生植物如何受到农业领域反复流行的影响。在本研究中,我们的目的是调查在野外收集的茄属植物（马铃薯的亲戚）的不同克隆对欧洲常见的致病疫霉的感染的抗性和耐受性是否不同。我们在实验室和田间进行了六种S.dulcamara基因型（克隆）的感染实验，并测量了感染程度和植物表现特征。在实验室里,评估的六种基因型从抗性到易感，根据感染后20天的感染程度来衡量。四个易感基因型中的两个基因型在感染程度和芽长度之间显示出二次（向下凹）关系，在中间感染值处具有最大芽长度。这个结果表明过度补偿，也就是说,受感染个体的增长。叶片数量随着感染程度的增加而减少，但是四种易感基因型的比率不同，表明耐性的遗传变异。在田野里,接种的基因型没有任何疾病症状，但是在生长季节结束时，接种植物的植物生物量高于对照组，与实验室检测到的过度补偿一致。我们得出的结论是，在S.dulcamara中，有迹象表明对传染性疟原虫感染具有抗性和耐受性。此外，一些基因型表现出过度补偿。了解植物耐受性和对病原体感染的过度补偿可以帮助扩大我们对自然种群中植物防御的理解，并有助于为经济上重要的作物病害开发更可持续的植物保护策略。
