Competition and facilitation among fungal plant parasites affect their life-history traits

Multi-infections may result in either competitive exclusion or coexistence on the same host of pathogen genotypes belonging to the same or different species. Epidemiological consequences of multiple infections, particularly how the development and transmission of a pathogen can be modified by the presence of another pathogen, are well documented. However, understanding how life history strategies of each pathogen modulate co-infection outcomes remains quite elusive. To analyze how co-infection drives changes in life history traits and affects co-existence in epidemic pathogens, we infected detached pea stipules with two fungal species, Peyronellaea pinodes and Phoma medicaginis var. pinodella (considering 2 strains per species), part of the ascochyta blight complex but presenting different life history strategies. All pairwise combinations (including self-pairs) between two strains of each species were tested. Strains were inoculated simultaneously, but apart from one another on the sti...同种或不同物种的病原基因型侵染同一宿主时，多重侵染可引发竞争性排斥或共存现象。多重侵染的流行病学效应，尤其是一种病原的生长发育与传播如何受另一种病原存在的调控，已有大量研究报道。然而，阐明每种病原的生活史策略如何调控共侵染结局，仍是当前尚未攻克的难题。为解析共侵染如何驱动流行性病原的生活史性状改变并影响其共存状态，本研究选取两种隶属于壳二孢萎蔫复合体（Ascochyta blight complex）但生活史策略存在显著差异的真菌作为研究材料：豌豆壳二孢（Peyronellaea pinodes）与苜蓿茎点霉豌豆变种（Phoma medicaginis var. pinodella），每个物种各设置2个菌株，通过侵染离体豌豆托叶开展实验。本实验测试了每个物种的两个菌株间的所有两两组合（包括自配对组合）。菌株同步接种，但彼此分隔于托叶的（原文末尾截断为"sti..."）