Berlin Anna, Samils Berit, Andersson Björn
Department of Forest Mycology and Plant Pathology, Swedish University of Agricultural Sciences, Box 7026, 750 07 Uppsala, Sweden.
Fungal Biol Biotechnol. 2017 May 3;4:3. doi: 10.1186/s40694-017-0032-3. eCollection 2017.
Cereal rust fungi ( spp.) are among the most economically important plant pathogens. These fungi have a complex life cycle, including five spore stages and two hosts. They infect one grass host on which they reproduce clonally and cause the cereal rust diseases, while the alternate host is required for sexual reproduction. Although previous studies clearly demonstrate the importance of the alternate host in creating genetic diversity in cereal rust fungi, little is known about the amount of novel genotypes created in each successful completion of a sexual reproduction event.
In this study, single sequence repeat markers were used to study the genotypic diversity within aecial clusters by genotyping individual aecial cups. Two common cereal rusts, causing stem rust and the causal agent of crown rust were investigated. We showed that under natural conditions, a single aecial cluster usually include several genotypes, either because a single pycnial cluster is fertilized by several different pycniospores, or because aecia within the cluster are derived from more than one fertilized adjoining pycnial cluster, or a combination of both.
Our results imply that although sexual events in cereal rust fungi in most regions of the world are relatively rare, the events that occur may still significantly contribute to the genetic variation within the pathogen populations.
谷物锈菌（ 属）是最重要的经济植物病原体之一。这些真菌具有复杂的生命周期，包括五个孢子阶段和两个寄主。它们感染一种禾本科寄主，在其上进行无性繁殖并引发谷物锈病，而有性繁殖则需要转主寄主。尽管先前的研究清楚地证明了转主寄主在谷物锈菌创造遗传多样性方面的重要性，但对于每次成功完成有性繁殖事件所产生的新基因型数量却知之甚少。
在本研究中，利用单序列重复标记通过对单个锈孢子器杯进行基因分型来研究锈孢子器簇内的基因型多样性。对引起茎锈病的两种常见谷物锈菌以及引起冠锈病的病原菌进行了调查。我们发现，在自然条件下，单个锈孢子器簇通常包含几种基因型，这要么是因为单个性孢子器簇被几种不同的性孢子受精，要么是因为簇内的锈孢子器源自一个以上受精的相邻性孢子器簇，或者是两者的结合。
我们的结果表明，尽管在世界大多数地区谷物锈菌的有性繁殖事件相对较少，但发生的这些事件仍可能对病原菌群体内的遗传变异有显著贡献。
