The role of the sexual cycle in escalating wheat rust diversity in the UK

小麦锈病是全球谷物生产的主要威胁。与锈菌病原体中常见的一样，小麦锈病需要两个宿主来完成它们的生命周期;茎锈病和黄锈病在小麦上进行无性繁殖，在小檗上完成有性繁殖，其中重组可以导致新基因型的出现。在英国，小檗的灭绝使茎锈病几乎完全灭绝。然而，在过去的十年中，小檗种植已经重新启动，并在许多主要的小麦种植区迅速发展。在英国，这在很大程度上是由濒危的小檗地毯蛾Pareulype berberata的栖息地保护计划推动的。这是令人担忧的，因为在同一时期，我们看到欧洲零星的茎锈病流行越来越多，包括远至瑞典和西西里的严重爆发。在英国，在我们的初步研究中，我们在2013年发现了一株被秆锈病感染的小麦植株，这说明了秆锈病感染英国小麦作物的潜力。此外，在2017年，我们在英国记录了几十年来第一次在小檗上发现的茎锈病。与此同时，我们在瑞典的合作者同年发现了来自小檗的第一个小麦茎锈性种群。该项目的总体目标是描述小檗上锈的组成，以确定这种大规模重新种植是否可以促进英国未来茎锈的重新出现，同时也增强了小麦黄锈的多样性。这将为今后设计和部署充分考虑到百慕大威胁的监测和管理战略提供重要信息。然而，它还必须仔细平衡将小麦锈病多样性加剧的风险降至最低的愿望，（如可能）保护小檗地毯蛾的栖息地。拟议的研究旨在：（1）确定英国小檗上锈病的组成，（2）确定小檗衍生的性锈病种群对英国小麦和大麦生产的风险，（3）建立一个英国小麦锈病传播风险模型和相关的管理措施。该研究项目将提供大量关于性周期在加剧谷物锈病多样性方面的作用的信息。此外，它还将提供重要信息，直接为英国各地的贝雷帽重新种植计划提供政策信息，并确定应避免或（如果植物已经存在）定期监测的高风险区域。在此，我们的目标是实现一个谨慎的平衡，管理农业社区的迫切需要，通过评估育种材料对小麦秆锈病的敏感性，确保英国小麦未来的恢复力，同时保护英国动物群的生物多样性。

Wheat rusts are a major threat to cereal production worldwide. As is common among rust pathogens, the wheat rusts require two hosts to complete their life cycles; stem and yellow rust undertake asexual reproduction on wheat and complete sexual reproduction on barberry (Berberis), where recombination can lead to emergence of novel genotypes. The eradication of barberry in the UK drove stem rust to almost complete extinction. However, over the past decade, barberry planting has been reinitiated and is advancing at speed in many major wheat growing regions. In the UK, this is largely driven by the habitat conservation programme for the endangered barberry carpet moth, Pareulype berberata. This is worrying because in the same time period we have seen an increasing number of sporadic stem rust epidemics in Europe, including severe outbreaks as far apart as Sweden and Sicily. Here in the UK in our preliminary study, we identified one wheat plant infected by stem rust in 2013 which illustrates the potential for stem rust to infect wheat crops in the UK. Furthermore, in 2017 we recorded for the first time in decades stem rust aecia on barberry in the UK. In parallel our collaborators in Sweden in the same year identified the first sexual population of wheat stem rust derived from barberry.The overall aim of this project is to characterize the composition of rust on Berberis to determine if this mass re-planting could be facilitating the future re-emergence of stem rust in the UK, whilst also enhancing wheat yellow rust diversity. This will provide vital information for the future design and deployment of surveillance and management strategies that fully consider the threat of Berberis. However, it must also carefully balance the desire to minimise the risk of intensifying wheat rust diversity with (where possible) protecting habitat for the barberry carpet moth.The proposed research aims to: (1) define the composition of rust on Berberis in the UK, (2), determine the risk of barberry-derived sexual rust populations to UK wheat and barley production, and (3) develop a UK risk model for wheat rust dispersal from Berberis and associated management actions. This research project will provide a wealth of information regarding the role of the sexual cycle in exacerbating the diversity of cereal rusts. Furthermore, it will provide vital information that will directly inform policy regarding the re-planting programme for Berberis across the UK and identify areas of high risk that should be avoided or (if plants are already present) regularly monitored. Herein, we aim to achieve a careful balance that manages the immediate needs of the farming community, ensures future resilience in UK wheat by accessing the susceptibility of breeding material to wheat stem rust, whilst conserving the biodiversity of UK fauna.