PDF(Pubmed)
Abstract：
Pathogen populations differ in the amount of genetic diversity they contain. Populations carrying higher genetic diversity are thought to have a greater evolutionary potential than populations carrying less diversity. We used published studies to estimate the range of values associated with two critical components of genetic diversity, the number of unique pathogen genotypes and the number of spores produced during an epidemic, for the septoria tritici blotch pathogen Zymoseptoria tritici. We found that wheat fields experiencing typical levels of infection are likely to carry between 3.1 and 14.0 million pathogen genotypes per hectare and produce at least 2.1-9.9 trillion pycnidiospores per hectare. Given the experimentally derived mutation rate of 3 × 10-10 substitutions per site per cell division, we estimate that between 27 and 126 million pathogen spores carrying adaptive mutations to counteract fungicides and resistant cultivars will be produced per hectare during a growing season. This suggests that most of the adaptive mutations that have been observed in Z. tritici populations can emerge through local selection from standing genetic variation that already exists within each field. The consequences of these findings for disease management strategies are discussed.
摘要：
病原体种群所包含的遗传多样性数量不同。具有较高遗传多样性的种群被认为比具有较少多样性的种群具有更大的进化潜力。我们使用已发表的研究来估计与遗传多样性的两个关键组成部分相关的值的范围，独特的病原体基因型的数量和在流行期间产生的孢子的数量，用于黑麦斑病病原体ZymoseptoriaTritici。我们发现，经历典型感染水平的麦田每公顷可能携带3.1至1,400万种病原体基因型，每公顷至少产生2.1-9.9万亿孢子。鉴于实验得出的每个细胞分裂每个位点3×10-10个替换的突变率，我们估计，在生长季节，每公顷将产生2700万至1.26亿个携带适应性突变的病原体孢子，以抵消杀菌剂和抗性品种。这表明在Z.tritici种群中观察到的大多数适应性突变可以通过局部选择从每个领域中已经存在的常备遗传变异中出现。讨论了这些发现对疾病管理策略的影响。
