Antagonistic competition moderates virulence in Bacillus thuringiensis
Antagonistic competition moderates virulence in Bacillus thuringiensis
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DOI：
10.1111/j.1461-0248.2011.01638.x
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发表时间：
2011-08-01
期刊：
影响因子：
8.8
通讯作者：
Raymond, Ben
中科院分区：
文献类型：
--
作者：
Garbutt, Jennie;Bonsall, Michael B.;Raymond, Ben
毒力进化的经典模型预测，如果更快的增长带来竞争力的提高，多重感染应该选择更高的毒力。然而，不同的寄生虫竞争模式（基于资源、拮抗、免疫操纵）可能导致对毒力产生不同影响的适应。使用实验进化方法，我们研究了这样的假设：混合菌株感染的选择将导致对抗性的增加，从而抵消毒力的投资。混合感染中的选择导致了对细菌昆虫病原体苏云金芽孢杆菌中竞争者的更好的抑制。在四个所选品系中，拮抗作用的增加与毒力的降低有关。此外，混合感染的毒力低于单一菌株感染，并且菌株之间的竞争往往会降低病原体在体内和体外的生长。由于毒力因子的高代谢成本和混合感染的高风险，这些细菌之间的恶意相互作用可能会受到青睐。
Classical models of the evolution of virulence predict that multiple infections should select for elevated virulence, if increased competitiveness arises from faster growth. However, diverse modes of parasite competition (resource-based, antagonism, immunity manipulation) can lead to adaptations with different implications for virulence. Using an experimental evolution approach we investigated the hypothesis that selection in mixed-strain infections will lead to increased antagonism that trades off against investment in virulence. Selection in mixed infections led to improved suppression of competitors in the bacterial insect pathogen Bacillus thuringiensis. Increased antagonism was associated with decreased virulence in three out of four selected lines. Moreover, mixed infections were less virulent than single-strain infections, and between-strain competition tended to decrease pathogen growth in vivo and in vitro. Spiteful interactions among these bacteria may be favoured because of the high metabolic costs of virulence factors and the high risk of mixed infections.