The impact of microbial communities on the incidence of foliar fungal disease symptoms in wheat

在受控环境中研究植物病害在控制/或最小化可能影响病害相互作用结果的其他因素方面具有若干优势。这包括限制暴露于各种环境压力以及尽量减少与其他生物（包括天然微生物群落）的相互作用。然而，这些实验可能不能完全转化为实际的田间情况，在实际的田间情况下，包括消极和积极的相互作用在内的额外压力几乎肯定会改变植物病原体相互作用的结果，这可能最终影响作物产量。在自然田间系统中，植物病原体在异质环境中引起疾病，其中不同的微生物群落可能对症状严重程度和/或营养获取产生消极或积极的影响。在不同的地上和地下微生物群落环境中，引起小麦主要叶面病害的微生物间相互作用的研究很少。本项目旨在了解小麦叶片上两种主要的全球致病真菌——小麦黑斑病（STB）的致病菌——小麦酵母菌（Zt）和小麦黑斑病（SNB）的致病菌——芽孢对生菌（Pn）如何影响小麦相关微生物群落，反之亦然。该项目将利用受控环境实验和实地取样监测真菌感染过程中微生物群落的变化以及不同微生物群落对叶面疾病的影响。拮抗和激动相互作用将被研究，微生物或微生物群落将被确定，它们可以改变由一种或两种真菌引起的小麦疾病的结果或严重程度。第二个目标将是鉴定和设计一种小麦叶片相关内生真菌，通过操纵2型分泌来产生真菌效应蛋白，以提高对不同小麦种质中效应蛋白敏感性的筛选率。本项目要检验的假设包括：1-在受控条件下，STB和SNB对相关的地下和地上微生物群落有不同的影响；2-对地上和/或地下微生物群落的人为操纵会影响STB和SNB3引起的叶面疾病症状；Zt和Pn在不同致病性和毒力成分上有缺陷的特定突变体对存在于植物体内的微生物群落有不同的影响在田间人工接种每种真菌病原体的小麦植株，与控制环境相比，会有不同的疾病症状和微生物关联。我们可以在小麦叶片相关内生微生物中鉴定和设计一种新的真菌效应剂传递系统。在受控环境中研究植物病害在控制/或最小化可能影响病害相互作用结果的其他因素方面具有若干优势。这包括限制暴露于各种环境压力以及尽量减少与其他生物（包括天然微生物群落）的相互作用。然而，这些实验可能不能完全转化为实际的田间情况，在实际的田间情况下，包括消极和积极的相互作用在内的额外压力几乎肯定会改变植物病原体相互作用的结果，这可能最终影响作物产量。在自然田间系统中，植物病原体在异质环境中引起疾病，其中不同的微生物群落可能对症状严重程度和/或营养获取产生消极或积极的影响。在不同的地上和地下微生物群落环境中，引起小麦主要叶面病害的微生物间相互作用的研究很少。

The study of plant diseases in controlled environments offers several advantages in terms of controlling / or minimising additional factors which might influence the outcome of the disease interaction. This includes limiting exposure to various environmental stresses as well as minimising interactions with other organisms including natural microbial communities. However these experiments may not translate completely into real field situations where the additional stresses including negative and positive interactions will almost certainly alter the outcome of a plant pathogen interaction, and this may ultimately affect crop yield.In natural field systems plant pathogens cause disease in heterogeneous environments where variable microbial communities may impact negatively or positively upon symptom severity and / or nutrient acquisition. Very few efforts have been made to address the interactions between organisms which can cause major foliar diseases of wheat within environments of variable above and below ground microbial communities.This project aims to understand how two major global disease-causing fungi on wheat leaves, Zymoseptoria tritici (Zt), the causal agent of Septoria tritici blotch (STB) and Parastagonospora nodorum (Pn), the causal agent of Septoria nodorum blotch (SNB), affect wheat-associated microbial communities and vice versa. The project will use both controlled environment experiments and field samples to monitor changes in microbial communities throughout fungal infection and changes in foliar diseases in response to distinct microbial communities. Antagonistic and agonistic interactions will be studied and microbes or microbial communities identified which can alter the outcome or severity of wheat disease caused by either or both fungi.A secondary objective will be to identify and engineer a wheat leaf associated endophytic fungus to produce fungal effector proteins via manipulation of Type 2 secretion to enhance the rate of screening for effector sensitivities in diverse wheat germplasm.The hypotheses to be tested in this project include1- That under controlled conditions STB and SNB have different impacts on associated below and above ground microbial communities2- That artificial manipulation of above and/or below ground microbial communities influences foliar disease symptomology caused by STB and SNB3- That particular mutants of Zt and Pn defective in different components of pathogenicity and virulence have distinct effects on microbial communities present within the infected leaf4- That wheat plants artificially inoculated by each fungal pathogen in the field will have different disease symptomology and microbial associations compared to controlled environments5- That we can identify and engineer a new fungal effector delivery system in a wheat leaf-associated endophytic microbe.The study of plant diseases in controlled environments offers several advantages in terms of controlling / or minimising additional factors which might influence the outcome of the disease interaction. This includes limiting exposure to various environmental stresses as well as minimising interactions with other organisms including natural microbial communities. However these experiments may not translate completely into real field situations where the additional stresses including negative and positive interactions will almost certainly alter the outcome of a plant pathogen interaction, and this may ultimately affect crop yield.In natural field systems plant pathogens cause disease in heterogeneous environments where variable microbial communities may impact negatively or positively upon symptom severity and / or nutrient acquisition. Very few efforts have been made to address the interactions between organisms which can cause major foliar diseases of wheat within environments of variable above and below ground microbial communities.