Rust fungi are obligate parasites, of plants, with complex and in many cases poorly known life cycles which may include host alteration and up to five spore types with haploid, diploid, and dikaryotic nuclear stages. This study supports that Thekopasora areolata , the causal agent of cherry‐spruce rust in Norway spruce, is a macrocyclic heteroecious fungus with all five spore stages which uses two host plants Prunus padus and Picea abies to complete its life cycle. High genotypic diversity without population structure was found, which suggests predominantly sexual reproduction, random mating and a high gene flow within and between the populations in Fennoscandia. There was no evidence for an autoecious life cycle resulting from aeciospore infection of pistillate cones that would explain the previously reported rust epidemics without the alternate host. However, within cones and scales identical multilocus genotypes were repeatedly sampled which can be explained by vegetative growth of the fertilized mycelia or repeated mating of mycelium by spermatia of the same genotype. The high genotypic diversity within cones and haplotype inference show that each pistillate cone is infected by several basidiospores. This study provides genetic evidence for high gene flow, sexual reproduction, and multiple infections of Norway spruce cone by the rust fungus T. areolata which expands the general understanding of the biology of rust fungi.

中文翻译：

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有性繁殖和挪威云杉球果被锈菌 Thekopsora areolata 多重感染的遗传证据。

锈菌是植物的专性寄生虫，具有复杂且在许多情况下鲜为人知的生命周期，其中可能包括宿主改变和多达五种具有单倍体、二倍体和双核核阶段的孢子类型。这项研究表明，挪威云杉樱桃云杉锈病的致病菌Thekopasora areolata是一种大环杂种真菌，具有所有五个孢子阶段，利用两种寄主植物Prunus padus和Picea abies来完成其生命周期。发现了没有种群结构的高基因型多样性，这表明芬诺斯坎迪亚种群内部和种群之间主要有性繁殖、随机交配和高基因流动。没有证据表明雌果的空孢子感染导致了自花生命周期，这可以解释先前报道的没有替代宿主的锈病流行。然而，在球果和鳞片内，重复取样了相同的多位点基因型，这可以通过受精菌丝体的营养生长或相同基因型的精子对菌丝体的重复交配来解释。球果内的高基因型多样性和单倍型推断表明，每个雌蕊球果都被多个担子孢子感染。这项研究为挪威云杉球果的高基因流、有性繁殖和锈菌T. areolata的多重感染提供了遗传证据，扩大了对锈菌生物学的一般认识。