How do fungi interact with the Gibberellic acid pathways in developing wheat ovules and what are the implications for resistance and yield

在英国，两种产生真菌毒素的小麦疾病对食品安全造成严重后果，GA与它们的疾病进展有关。该项目涉及多种技术，包括显微镜、代谢物提取和植物病理学，所有这些都与英国最有价值的作物物种——小麦有关。谷物受真菌病原菌感染，在世界范围内造成谷物产量损失和毒素污染。英国谷物生产的两种重要疾病是由真菌引起的，它们具有不同的穗/谷物感染模式。真菌Claviceps purpurea （Cp）感染小麦胚珠，用真菌菌核取代种子，产生麦角菌。麦角菌核中充满了一种有毒的生物碱，这种生物碱在人类身上引起了中世纪的圣安东尼大火。更多的机会性镰刀菌复合病原体（引起镰刀菌头疫病；FHB）感染小麦穗的所有部位，导致生长中的谷物产生有害的真菌毒素。NIAB的突破性研究表明，Cp利用植物的赤霉素酸（GA）途径建立感染和繁殖。对麦角菌的部分抗性被发现与小麦矮化基因Rht-1Bb和Rht-1Db共定位（Gordon et al . 2015; TAG in press）。这些DELLA蛋白突变体对GA无反应，导致生长迟缓（Peng et al . 1999; Nature 40: 256）。初步结果表明，在胚珠中特异表达GA2氧化酶1的转基因小麦株系中，降低GA水平可减少Cp感染和减小菌核。对FHB的抗性，可以根据感染类型分类，也被证明与小麦矮化基因有关（Srinivasachary等人2009；TAG 118: 695）， GA被假设在真菌在穗内传播的能力中发挥作用。与加拿大伙伴的国际合作已经产生了新的资源，包括具有非常好的麦角菌抗性的六倍体合成品系（Menzies et al . 2002）和一个定位种群，以便绘制相关基因。我们有来自该群体的混合小麦-真菌转录组数据，这有助于确定真菌激发子目标和进一步的标记。-全GA代谢分析，以确定转基因和野生型系在Cp和FHB疾病进展过程中的GA水平。-锁骨镰刀菌和镰刀菌的转录组和基因遗传分析，分析它们共同选择宿主基因遗传途径或产生自己的基因遗传途径的能力。-在英国小麦品系中培育真正的麦角菌抗性的机会。

Theme: Agriculture and Food SecurityTwo mycotoxin-producing wheat diseases have serious consequences for food safety in the UK and have GA implicated in their disease progression. This project involves a variety of techniques including microscopy, metabolite extraction and plant pathology and all with the UK's most valuable crop species - wheat. Infection of grain by fungal pathogens results in yield loss and toxin contamination in cereal crops worldwide. Two important diseases of UK cereal production are caused by fungi with contrasting modes of ear/grain infection. The fungus Claviceps purpurea (Cp) infects wheat ovules, replacing the seed with fungal sclerotia and causing Ergot. Ergot sclerotia are full of a toxic alkaloids that in humans caused the medieval disease St Antony's Fire. The more opportunistic Fusarium pathogen complex (causing Fusarium Head Blight; FHB) infects all parts of the wheat ear, leading to production of harmful mycotoxins within the developing grain.Ground-breaking research at NIAB indicates that Cp co-opts the plant's Gibberellic Acid (GA) pathways to establish infection and reproduce. Partial resistance to Ergot has been found to co-locate with the wheat dwarfing genes, Rht-1Bb and Rht-1Db (Gordon et al 2015; TAG in press). These DELLA protein mutants are non-responsive to GA, resulting in growth retardation (Peng et al 1999; Nature 40: 256). Preliminary results in wheat transgenic lines expressing a bean GA2 oxidase1 specifically in ovules indicates that lowering GA levels results in reduced Cp infection and smaller sclerotia. Resistance to FHB, which can be classified by infection type, has also been shown to be linked to the wheat dwarfing genes (Srinivasachary et al 2009; TAG 118: 695), GA being hypothesised to play a role in the ability of the fungus to spread within the ear. An international collaboration with Canadian partners has yielded new resources including a hexaploid synthetic line containing very good ergot resistance (Menzies et al 2002) and a mapping population in order to map the genes responsible. We have mixed wheat-fungal transcriptome data from that population that is helping to identify fungal elicitors targets and further markers.Outline:- Full GA metabolic analysis to determine levels of GA during Cp and FHB disease progression in transgenic and wildtype lines. - Transcriptome and GA analysis of Claviceps and Fusarium species' ability to co-opt host GA pathways or produce their own.- An opportunity to breed real ergot resistance into UK wheat lines.