Chair of Phytopathology, TUM School of Life Sciences, Technical University of Munich, Emil-Ramann-Str. 2, 85354 Freising, Germany.
Section of Population Genetics, TUM School of Life Sciences, Technical University of Munich, Liesel-Beckmann Str. 2, 85354 Freising, Germany.
Proc Biol Sci. 2020 Dec 23;287(1941):20202723. doi: 10.1098/rspb.2020.2723.
Natural plant populations encounter strong pathogen pressure and defence-associated genes are known to be under selection dependent on the pressure by the pathogens. Here, we use populations of the wild tomato to investigate natural resistance against , a well-known ascomycete pathogen of domesticated tomatoes. Host populations used are from distinct geographical origins and share a defined evolutionary history. We show that distinct populations of differ in resistance against the pathogen. Screening for major resistance gene-mediated pathogen recognition throughout the whole species showed clear geographical differences between populations and complete loss of pathogen recognition in the south of the species range. In addition, we observed high complexity in a () locus, underlying the recognition of in central and northern populations. Our findings show that major gene-mediated recognition specificity is diverse in a natural plant-pathosystem. We place major gene resistance in a geographical context that also defined the evolutionary history of that species. Data suggest that the underlying loci are more complex than previously anticipated, with small-scale gene recombination being possibly responsible for maintaining balanced polymorphisms in the populations that experience pathogen pressure.
自然植物种群面临强大的病原体压力，已知防御相关基因受到病原体压力的选择。在这里，我们使用野生番茄种群来研究对的天然抗性，这是一种众所周知的茄科病原体。所用的宿主种群来自不同的地理起源，并具有明确的进化历史。我们表明，不同的种群对病原体的抗性存在差异。在整个物种中筛选主要抗性基因介导的病原体识别显示，种群之间存在明显的地理差异，并且在物种范围的南部完全丧失了病原体识别。此外，我们在（）基因座中观察到了高度的复杂性，这是中北部种群识别的基础。我们的研究结果表明，主要基因介导的识别特异性在自然植物-病原体系统中是多样化的。我们将主要基因抗性置于一个确定该物种进化历史的地理背景下。数据表明，潜在的基因座比先前预期的更为复杂，小规模的基因重组可能负责维持经历病原体压力的种群中的平衡多态性。
