Evolution of morphological but not aggressiveness‐related traits following a major resistance breakdown in the poplar rust fungus, Melampsora larici‐populina

Crop varieties carrying qualitative resistance to targeted pathogens lead to strong selection pressure on parasites, often resulting in resistance breakdown. It is well known that qualitative resistance breakdowns modify pathogen population structure but few studies have analysed the consequences on their quantitative aggressiveness-related traits. The aim of this study was to characterize the evolution of these traits following a resistance breakdown in the poplar rust fungus, Melampsora larici-populina. We based our experiment on three temporal populations sampled just before the breakdown event, immediately after and four years later. First, we quantified phenotypic differences among populations for a set of aggressiveness traits on a universally susceptible cultivar (infection efficiency, latent period, lesion size, mycelium quantity, and sporulation rate) and one morphological trait (mean spore volume). Then we estimated heritability to establish which traits could be subjected to ...

携带针对靶标病原菌的定性抗性的作物品种会对病原菌施加强烈的选择压力，往往会引发抗性崩溃（resistance breakdown）。众所周知，定性抗性的崩溃会改变病原菌的种群结构，但鲜有研究分析其对病原菌定量致病性相关性状的影响。本研究旨在解析落叶松杨栅锈菌（Melampsora larici-populina）发生抗性崩溃后，此类相关性状的演化规律。本实验以三个时序种群为研究材料，分别于抗性崩溃事件发生前、发生后即刻以及发生四年后进行采样。首先，我们在一个普遍感病品种上量化了各时序种群的一系列致病性性状（侵染效率、潜育期、病斑大小、菌丝量以及产孢率）以及一项形态性状（平均孢子体积）的表型差异；随后我们通过估算遗传力，以明确哪些性状可能受到……