Decoding the chitin signatures generated by Xylella fastidiosa

解码苛养木杆菌产生的几丁质特征

• 批准号: 525893783
• 负责人: Professorin Dr. Silke Robatzek
• 金额: --
• 依托单位: Institut für Genetik
• 依托单位国家: 德国
• 项目类别: Priority Programmes
• 资助国家: 德国
• 项目状态: 未结题
• 来源: https://gepris.dfg.de/gepris/projekt/525893783?language=en
• 关键词: Decoding; chitin; signatures; generated; Xylella

The ability to degrade chitin is essential for the survival and colonization success of fungal and bacterial pathogens, many of which are causal agents of agronomically-important diseases. For bacterial pathogens, which lack chitin, the degradation of chitin plays a major role in opposing host-colonizing fungi and surviving in its vector, if transmitted by insects. One of the pathogens ranked in the “list of priority pests” for Europe is Xylella fastidiosa. This insect-transmitted bacterium is the cause of the OLIVE QUICK DECLINE SYNDROME (OQDS) and important for outbreaks over the past ten years. The urgency to develop an understanding how X. fastidiosa colonizes its hosts is apparent from the lack of disease control. Previously it has been reported that a proposed chitinase, chiA, is secreted by X. fastidiosa and i) confers utilization of chitin as a carbon source, potentially from its insect vectors and xylem-colonizing fungi, ii) promotes transmission by insect vectors, and iii) is required for systemic infection in plants, maybe opposing plant-colonizing fungi. Our focus is chiA, because this bacterial chitinase iv) carries an unusual loop in its modelled 3D structure that could determine substrate specificity, and v) likely releases chitin oligomers that could modulate immune responses in hosts of X. fastidiosa. Although chitinases have been studied since decades, we have little knowledge on substrate-structure-product-bioactivity relationships, which are key to understanding its role as virulence factors. Here, our goal is to answer two key questions: 1. How does X. fastidiosa degrade chitin? Profiling chiA activity and specificity using a series of defined chitin substrates and different organismal sources will reveal degradation products then subjected to bioactivity analysis. Structure-function relationships will be explored in silico, in vitro and in vivo. 2. What is the immunomodulatory potential of chitin oligomers produced by X. fastidiosa? Comparing different immune responses to chiA products in model and crop hosts, together with assessing pattern recognition receptor-mediated immunity are likely to provide insights into this question. Being an important virulence factor, our overall aim is to better understand the molecular details of chiA function and clarify its role in systemic plant infection. We envisage that this knowledge could be useful for biotechnological purposes.

降解几丁质的能力对于真菌和细菌病原体的存活和定殖成功是必不可少的，其中许多是农学上重要的疾病的致病因子。对于缺乏几丁质的细菌病原体，如果通过昆虫传播，几丁质的降解在对抗宿主定殖真菌和在其载体中存活方面起主要作用。在欧洲的“优先害虫清单”中排名的病原体之一是苛养木杆菌。这种昆虫传播的细菌是橄榄快速衰退综合征（OQDS）的原因，并且在过去十年中对爆发很重要。迫切需要了解X. fastidiosa定殖其宿主是显而易见的，从缺乏疾病控制。以前有报道说，拟几丁质酶，chiA，分泌的X。fastidiosa和i）赋予几丁质作为碳源的利用，可能来自其昆虫载体和定殖于木质部的真菌，ii）促进通过昆虫载体的传播，和iii）是植物中的系统感染所需的，可能对抗定殖于植物的真菌。我们的重点是chiA，因为这种细菌几丁质酶iv）在其模拟的3D结构中携带一个不寻常的环，可以确定底物特异性，v）可能释放几丁质低聚物，可以调节X宿主的免疫反应。苛养。虽然几丁质酶已经研究了几十年，但我们对底物-结构-产物-生物活性的关系知之甚少，这是理解其作为毒力因子的关键。在这里，我们的目标是回答两个关键问题：1。如何X。苛养菌降解几丁质？使用一系列确定的几丁质底物和不同的生物来源分析chiA活性和特异性将揭示降解产物，然后进行生物活性分析。将在计算机模拟、体外和体内探索结构-功能关系。2.什么是免疫调节潜力的甲壳素低聚物产生的X。fastidiosa？比较不同的免疫反应chiA产品在模型和作物宿主，连同评估模式识别受体介导的免疫可能会提供深入了解这个问题。作为一个重要的毒力因子，我们的总体目标是更好地了解chiA功能的分子细节，并阐明其在系统性植物感染中的作用。我们设想，这种知识可能对生物技术目的有用。