Strategies for integrated deployment of host resistance and fungicides to sustain effective crop protection.

综合部署宿主抗性和杀菌剂以维持有效作物保护的策略。

• 批准号: BB/K020900/1
• 负责人: Frank Van Den Bosch
• 金额: $ 30.11万
• 依托单位: Rothamsted Research
• 依托单位国家: 英国
• 项目类别: Research Grant
• 财政年份: 2014
• 资助国家: 英国
• 起止时间: 2014 至 无数据
• 项目状态: 已结题
• 来源: https://gtr.ukri.org/projects?ref=BB%2FK020900%2F1
• 关键词: Strategies; integrated; deployment; host; resistance

Sustainable crop protection is of key importance to food security and to ensure that crops make efficient use of resources (land, nitrogen and water). Fungicides and resistant cultivars are the predominant control measures against most crop diseases. However, control imposes a selection pressure on pathogen populations, leading to the evolution of pathogen strains which are less sensitive to the fungicides used or which are able to overcome host resistance (virulent pathogen strains). For example, potato late blight, caused by Phytophthora infestans, is managed by fungicide spray programmes, complemented by partial host resistance in some potato cultivars. Recently the pathogen population has changed: a loss of field efficacy of fluazinam (a widely used fungicide) has been reported, and new virulences have evolved, resulting in downgrading of cultivar resistance ratings.Integrated control, where two or more control measures are applied, is widely believed to be more sustainable than over-reliance on one control option. There is however surprisingly little mechanistic understanding of the effects on pathogen evolution of combining deployment of fungicides and crop resistance genes. The evolution of fungicide insensitivity and the evolution of virulence are studied in isolation, despite a strong rationale for their being interactions between the two processes. New virulent or resistant strains gain a competitive advantage over existing 'wild-type' strains because they are able to grow more rapidly than wild-type strains in the presence of the control measure that they are able to overcome. However, epidemics of a new virulent strain will still be slowed by fungicides, thus reducing its competitive advantage. Hence, fungicides may slow selection for virulence and, by a similar process, cultivar resistance may slow selection for fungicide insensitivity. The following hypotheses will be tested:H1: Deployment of crop resistance reduces selection for fungicide insensitivity.H2: Deployment of fungicides reduces selection for virulence.H3: How crop resistance genes and fungicides are integrated is a key determinant of the durability of control.Outcomes: The project will use experimental and modelling approaches to quantify the durability of disease control strategies integrating fungicide treatments and cultivar resistance. The directly applied outcome of the project is a fungicide and cultivar resistance based strategy for potato blight to be implemented through the Potato Council and industry partners. The further outcomes are generic methods to develop, parameterise and validate models that can be used to quantify integrated sustainable disease control strategies for pathogen-crop systems.This work is made possible by recent progress in two areas. Firstly, changes in virulence in a range of pathogen species have been shown to be related to well characterised mutations in 'effector genes'. Testing for these mutations allows the proportion of virulent strains to be quantified in field experiments. Treatments can then be compared to measure the extent to which they affect selection for new strains. Fungicide insensitive strains can be tracked by similar methods. Secondly, epidemiological models have been tested against experimental data and found to give good predictions of the effect of fungicide treatments on selection for insensitive strains. Similar models have been developed to represent virulence evolution and it is now feasible to couple these two types of model to study the effects of integrated control. Field experiments will generate epidemiological data and pathogen samples. The samples will be tested to quantify changes in the frequency of virulent and insensitive strains, under different treatments, to test hypotheses 1 and 2. The resulting data will be used to test a coupled mathematical model, which will then be used to explore integrated disease management strategies under hypothesis 3.

可持续作物保护对粮食安全和确保作物有效利用资源（土地、氮和水）至关重要。杀菌剂和抗病品种是防治大多数作物病害的主要措施。然而，控制对病原体种群施加了选择压力，导致病原体菌株的进化，这些菌株对所使用的杀菌剂不太敏感，或者能够克服宿主的抗性（毒性病原体菌株）。例如，马铃薯晚疫病是由马铃薯疫霉引起的，通过杀菌剂喷洒方案加以管理，并在某些马铃薯品种中辅以部分宿主抗性。最近，病原菌种群发生了变化：据报道，氟西南（一种广泛使用的杀菌剂）的田间药效丧失，新的毒力已经进化，导致品种抗性等级下降。人们普遍认为，综合控制，即采用两种或两种以上的控制措施，比过分依赖一种控制办法更具有可持续性。然而，令人惊讶的是，人们对杀菌剂和作物抗性基因联合施用对病原体进化的影响的机制知之甚少。杀菌剂不敏感的进化和毒力的进化是分开研究的，尽管它们是两个过程之间的相互作用的强有力的理由。新的毒力或耐药菌株比现有的“野生型”菌株具有竞争优势，因为在它们能够克服的控制措施存在的情况下，它们能够比野生型菌株生长得更快。然而，一种新的毒性菌株的流行仍然会被杀菌剂减缓，从而降低其竞争优势。因此，杀菌剂可能会减缓毒力的选择，通过类似的过程，品种抗性可能会减缓杀菌剂不敏感的选择。以下假设将被检验：H1：作物抗性的部署减少了对杀菌剂不敏感的选择。H2：使用杀菌剂减少了对毒力的选择。H3：如何整合作物抗性基因和杀菌剂是控制持久性的关键决定因素。成果：该项目将使用实验和建模方法，量化结合杀菌剂治疗和品种抗性的疾病控制战略的持久性。该项目的直接应用成果是通过马铃薯理事会和行业合作伙伴实施一项基于杀菌剂和品种抗性的马铃薯疫病防治战略。进一步的结果是开发、参数化和验证模型的通用方法，这些模型可用于量化病原体-作物系统的综合可持续疾病控制策略。最近在两个领域取得的进展使这项工作成为可能。首先，一系列病原体物种的毒力变化已被证明与“效应基因”的良好特征突变有关。对这些突变的检测可以在野外实验中对毒性菌株的比例进行量化。然后可以比较处理方法，以衡量它们对新菌株选择的影响程度。对杀菌剂不敏感的菌株可以用类似的方法进行追踪。其次，流行病学模型已经根据实验数据进行了测试，发现可以很好地预测杀菌剂处理对不敏感菌株选择的影响。类似的模型已经被开发来表示毒力的进化，现在可以将这两种模型结合起来研究综合控制的效果。现场实验将产生流行病学数据和病原体样本。将对样本进行测试，以量化在不同处理下毒性和不敏感菌株频率的变化，以检验假设1和2。结果数据将用于测试耦合数学模型，然后用于探索假设3下的综合疾病管理策略。

项目成果

Quantitative resistance can lead to evolutionary changes in traits not targeted by the resistance QTLs.

• DOI: 10.1111/eva.12130
• 发表时间: 2014-03
• 期刊: Evolutionary applications
• 影响因子: 4.1
• 作者: Van den Berg F;Lannou C;Gilligan CA;van de Bosch F
• 通讯作者: van de Bosch F