Bilateral BBSRC-Embrapa: Exploiting natural and induced variation to increase Fusarium head blight and brusone resistance in wheat

小麦赤霉病和小麦稻瘟病是巴西小麦的两种毁灭性病害，在巴西造成严重的产量损失。这两种病原体严重影响小麦穗，直接损害谷物的质量和产量。在缺乏抗性品种的情况下，目前的疾病控制严重依赖于昂贵的杀菌剂，对巴西来说是不可持续的，并且只有部分有效。由真菌Magnaporthe magnaporthe引起的马勃龙于1985年首次在巴西南部被发现，但此后蔓延到阿根廷，玻利维亚和巴拉圭。这种疾病会导致总产量损失，2009年巴西小麦产量下降了30%。重要的是，巴西品种对布鲁松的敏感性排除了它们在塞拉多地区的种植，塞拉多地区有500万公顷的未利用潜力可供扩大，这将提高巴西这种基本主食的自给率。镰刀菌头枯病主要由真菌禾谷镰刀菌引起，在巴西和英国都是一种严重的疾病。除了产量和质量的显著损失外，FHB的一个主要问题是谷物被诸如脱氧雪腐镰刀菌烯醇（DON）的地衣霉烯真菌毒素污染。欧盟和巴西都规定了谷物和谷物产品中DON的最高允许水平。在巴西，严重的FHB爆发频率增加。2014年，FHB非常严重，以至于南里奥格兰德州和西部地区的小麦产量损失超过60%，2014年一些农民损失了超过80%的布鲁松+目前迫切需要鉴定和鉴定对FHB和布鲁松的抗性来源，并确保引入控制一种疾病的基因不会损害对另一个的抵抗。在巴西小麦中已鉴定出对布鲁松的中等水平抗性，但这种抗性的遗传基础尚不清楚。在幼苗中表达的抗性并不总是在成年植株中表达，因此在成年植株中评估抗性是必要的。对FHB的抗性通常由几个中/弱效应的基因控制，这些基因在遗传上被定义为数量性状位点（QTL）。虽然巴西小麦品种对赤霉病的抗性差异很大，有些品种具有中等抗性，但没有发现具有来自亚洲来源的主要Fhb 1抗性的品种。因此，大多数FHB抗性的巴西品种的遗传基础是未知的，并建议他们包含新的电阻，可以与其他地方的结合，以培育非常高的抗性小麦品种。该项目将使用一系列的尖端方法来确定抗性布鲁森和FHB疾病的遗传基础。我们将确定基因组的哪些部分含有增加FHB和/或布鲁松抗性的基因，并确定对一种疾病的抗性增加是否与对另一种疾病的易感性增加有关。我们还将确定小麦中降低对这两种疾病抗性的基因。这将为提高小麦对赤霉病和布鲁松的抗性提供一种补充方法。我们会制造DNA标记，让植物育种者在育种计划中追踪有益基因的存在，并确保他们的品种对这两种疾病都有高度的抵抗力。这项工作的结果将使巴西和世界上这些疾病流行的其他地方的植物育种者受益。这将降低种植者的作物损失风险，并降低谷物中霉菌毒素积累对消费者的风险。这将导致减少对杀真菌剂的依赖，以控制这些疾病，这反过来将有利于种植者和环境。

Fusarium head blight (FHB) and wheat blast (brusone) are two devastating diseases of wheat that cause major yield losses in Brazil. Both pathogens severely affect wheat heads with direct damage to the grain, both in terms of quality and yield. In the absence of resistant varieties, current disease control relies heavily on fungicides that are costly, non-sustainable for Brazil, and only partially effective.Brusone, caused by the fungus Magnaporthe oryzae, was first identified in southern Brazil in 1985 but has since spread into Argentina, Bolivia, and Paraguay. The disease can cause total yield loss of yield and in 2009 brusone cut Brazilian wheat production by up to 30%. Importantly, the susceptibility of Brazilian varieties to brusone precludes their cultivation in the Cerrado region, an unused potential of 5 million ha for expansion that would improve Brazilian self-sufficiency of this essential staple.Fusarium head blight, caused primarily by the fungus Fusarium graminearum, is a serious disease in both Brazil and the UK. In addition to the very significant yield and quality losses, a major concern with FHB is the contamination of grain with trichothecene mycotoxins such as deoxynivalenol (DON). Both the European Union and Brazil have imposed maximum permissible levels for DON in cereals and cereal products. In Brazil, severe FHB outbreaks have increased in frequency. In 2014 FHB was so severe that more than 60% of wheat yield was lost in the State of Rio Grande do Sul and in the western region in 2014 some farmers lost more than 80% to the combination of brusone + FHB.There is an urgent need to identify and characterise sources of resistance to both FHB and brusone and ensure that the introduction of genes to control one disease does not compromise resistance to the other. Moderate levels of resistance to brusone have been identified in Brazilian wheat but the genetic basis of this resistance is unclear. Resistance expressed in seedlings is not always expressed in adult plants making it essential that resistance is assessed in adult plants.Resistance to FHB is generally controlled by several genes of moderate/weak effect that are defined genetically as quantitative trait loci (QTL). Although Brazilian wheat varieties differ widely in their resistance to FHB with some being moderately resistant, no variety was found to possess the major Fhb1 resistance originating from Asian sources. Thus the genetic basis of the most FHB-resistant Brazilian cultivars is not known and suggests that they contain novel resistances that could be combined with those from elsewhere to breed very highly resistant wheat varieties.This project will use a range of cutting-edge approaches to identify the genetic basis of resistance to brusone and FHB disease. We will identify which parts of the genome contain genes that increase FHB and/or brusone resistance and determine whether increased resistance to one disease is associated with increased susceptibility to the other. We will also identify genes in wheat that reduce resistance to the two diseases. This will provide a complementary approach to increasing resistance to FHB and brusone in wheat. We will produce DNA markers to enable plant breeders to follow the presence of the beneficial genes in their breeding programmes and ensure that their varieties are highly resistant to both diseases. The results from this work will benefit plant breeders in Brazil and elsewhere across the world where these diseases are prevalent. This should lead to reduced risk of crop losses to growers and reduced risk to consumers from mycotoxins accumulating in grain. It will lead to a reduced reliance on fungicides to control these diseases which, in turn will benefit, growers and the environment.