INRA, UR407 Pathologie Végétale, Montfavet, France.
J Evol Biol. 2012 Nov;25(11):2242-52. doi: 10.1111/j.1420-9101.2012.02600.x. Epub 2012 Sep 4.
Adaptation of populations to new environments is frequently costly due to trade-offs between life history traits, and consequently, parasites are expected to be locally adapted to sympatric hosts. Also, during adaptation to the host, an increase in parasite fitness could have direct consequences on its aggressiveness (i.e. the quantity of damages caused to the host by the virus). These two phenomena have been observed in the context of pathogen adaptation to host's qualitative and monogenic resistances. However, the ability of pathogens to adapt to quantitative polygenic plant resistances and the consequences of these potential adaptations on other pathogen life history traits remain to be evaluated. Potato virus Y and two pepper genotypes (one susceptible and one with quantitative resistance) were used, and experimental evolutions showed that adaptation to a quantitative resistance was possible and resulted in resistance breakdown. This adaptation was associated to a fitness cost on the susceptible cultivar, but had no consequence either in terms of aggressiveness, which could be explained by a high tolerance level, or in terms of aphid transmission efficiency. We concluded that quantitative resistances are not necessarily durable but management strategies mixing susceptible and resistant cultivars in space and/or in time should be useful to preserve their efficiency.
由于生活史特征之间存在权衡，因此种群对新环境的适应通常是代价高昂的，因此寄生虫预计会适应同域的宿主。此外，在适应宿主的过程中，寄生虫的适应性增加可能会对其侵袭性（即病毒对宿主造成的损害量）产生直接影响。这两种现象在病原体适应宿主定性和单基因抗性的背景下已经观察到。然而，病原体适应植物数量多基因抗性的能力以及这些潜在适应对其他病原体生活史特征的影响仍有待评估。使用了马铃薯 Y 病毒和两种辣椒基因型（一种易感和一种具有数量抗性），实验进化表明，适应数量抗性是可能的，并且导致抗性丧失。这种适应与易感品种的适应性成本有关，但在侵袭性方面没有任何后果，这可以用高水平的耐受性来解释，也可以用蚜虫传播效率来解释。我们得出的结论是，数量抗性不一定持久，但是在空间和/或时间上混合使用易感和抗性品种的管理策略应该有助于保持其效率。
