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。在小麦锈病病原菌中很常见，小麦锈病需要两个寄主来完成它们的生活史；茎和黄锈病在小麦上进行无性繁殖，在小李(Berberis)上进行有性繁殖，重组可以导致新的基因类型的出现。英国杜绝了树干锈病，使其几乎完全灭绝。然而，在过去的十年里，许多小麦主产区重新启动了巴厘树种植，并正在快速推进。在英国，这在很大程度上是由濒危的羽毛蛾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，我们在欧洲看到越来越多的零星茎锈病流行，包括相距遥远的瑞典和西西里的严重疫情。在英国，在我们的初步研究中，我们在2013年发现了一株感染茎锈病的小麦植株，这表明茎锈病可能会感染英国的小麦作物。此外，2017年，我们在英国记录到了几十年来第一次枝条锈病AECIA。与此同时，我们在瑞典的合作者在同年确定了第一个来自理发树的小麦茎锈病有性种群。该项目的总体目标是表征柏柏利斯上的锈菌成分，以确定这种大规模的重新种植是否可以促进未来在英国重新出现小麦茎锈病，同时还增强了小麦黄锈病的多样性。这将为今后设计和部署充分考虑到柏柏利威胁的监测和管理战略提供重要信息。然而，它还必须仔细权衡将强化小麦锈菌多样性的风险降至最低的愿望和(如果可能的话)保护小叶蛾栖息地的愿望。拟议的研究旨在：(1)确定英国小腿病上的锈菌成分，(2)确定由草莓衍生的性锈菌种群对英国小麦和大麦生产的风险，以及(3)开发英国小麦锈病从小叶蜂扩散的风险模型和相关的管理行动。这一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，它将提供重要信息，直接为英国各地重新种植柏柏利的政策提供信息，并确定应该避免或(如果已经有植物存在)定期监测的高风险地区。在这里，我们的目标是实现谨慎的平衡，通过利用育种材料对小麦茎锈病的易感性，同时保护英国动物的生物多样性，来管理农业社区的迫切需求，确保英国小麦未来的弹性。

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.