Does induced phytotoxicity in apple replant disease affect Malus domestica roots?

苹果重植病中诱导的植物毒性是否影响苹果根？

• 批准号: 423738181
• 负责人: Dr. Stefan Weiß
• 金额: --
• 依托单位: Institut für Gartenbauliche Produktionssysteme
• 依托单位国家: 德国
• 项目类别: Research Grants
• 财政年份: 2019
• 资助国家: 德国
• 起止时间: 2018-12-31 至 无数据
• 项目状态: 未结题
• 来源: https://gepris.dfg.de/gepris/projekt/423738181?language=en
• 关键词: Does; induced; phytotoxicity; apple; replant

Apple (Malus domestica) is one of the most important cultivated fruits worldwide. In tree nurseries, plants are replanted frequently (2-3 years), which leads to diminished crop productivity, also known as apple replant disease (ARD). ARD can be defined as “a harmfully disturbed physiological and morphological reaction of apple plants to soils that faced alterations in their (micro-) biome due to the previous apple cultures”. Formerly, biologically broad-spectrum soil fumigants were used to control ARD. Nevertheless, application intricacy, high cost and hazards to environment and human health are problematic. Therefore, breeding and/or selecting less sensitive genotypes would present a more sustainable solution to ARD. However, the development of ARD trait associated markers relies on a better understanding of molecular reactions in planta to unravel disease etiology. Recently, phytoalexin biosynthesis genes were found to be strongly up-regulated after seven days of culture on ARD soil compared to disinfected ARD soil. It was revealed that the phytoalexins accumulated in the root system in very high concentrations leading to potential phytotoxicity. ABC transporters which are involved in the translocation and exudation of phytoalexins did not show any regulation leading to the assumption that phytoalexins may not be exuded into the soil under ARD conditions and therefore accumulate in the roots in very high concentrations. Additionally, the vacuolar transport may be hindered as well leading to the lack of detoxification of the accumulated substances. A potential reason for the proposed lack of exudation of phytoalexins or of sequestration into vacuoles via ABC transporters may be the generation of toxic cyanide levels in ARD affected plants leading to less ATP availability for ABC transporters to transport phytoalexins in ARD roots. The goal of the present project is to unravel the role of ARD induced phytoalexins on the ARD syndrome and to elucidate molecular reactions in ARD affected plants. The focus will be on deducing their role in ARD considering further interacting genes/proteins. Toxicity and localization of the compounds will be analyzed as well as detoxification mechanisms, e.g. transport from the cytoplasm. Furthermore, additional toxic byproducts in cyanide metabolism as well as energy supply will be investigated more closely to achieve a detailed overview of molecular mechanisms of ARD. Fluorescence in situ hybridization, microscopy, gene expression studies and metabolic analyses will be employed to achieve this goal. Comparisons between a sensitive and a less sensitive genotype will provide knowledge for the early prediction of markers of ARD severity in soils and will help in breeding programs to select ARD tolerant apple plants.

苹果（Malus domestica）是全球最重要的栽培水果之一。在果树苗圃中，植物经常（2-3年）重新种植，这导致作物生产力下降，也被称为苹果重新种植病（ARD）。ARD可以定义为“苹果植株对土壤的一种有害的生理和形态的扰动反应，这种土壤由于之前的苹果培养而面临着（微）生物群系的改变”。以前，生物广谱土壤熏蒸剂用于控制ARD。然而，应用的复杂性、高成本和对环境和人类健康的危害是问题。因此，培育和/或选择不太敏感的基因型将是解决ARD的更可持续的方法。然而，ARD性状相关标记的开发依赖于对植物分子反应的更好理解，以揭示疾病的病因。最近发现，与消毒后的ARD土壤相比，在ARD土壤中培养7天后，植物抗菌素生物合成基因被强烈上调。结果表明，植物抗毒素在根系中以非常高的浓度积累，导致潜在的植物毒性。参与植物抗菌素转运和分泌的ABC转运体没有表现出任何调节，导致植物抗菌素在ARD条件下可能不会分泌到土壤中，因此在根系中以非常高的浓度积累。此外，液泡运输也可能受到阻碍，导致积累的物质缺乏解毒作用。植物抗菌素分泌不足或通过ABC转运蛋白被固存到液泡中的潜在原因可能是受ARD影响的植物体内产生的有毒氰化物水平导致ABC转运蛋白在ARD根中运输植物抗菌素的ATP可用性减少。本项目的目的是揭示ARD诱导的植物抗毒素在ARD综合征中的作用，并阐明ARD受影响植物的分子反应。重点将是考虑进一步相互作用的基因/蛋白质来推断它们在ARD中的作用。将分析化合物的毒性和定位以及解毒机制，例如从细胞质转运。此外，将更密切地研究氰化物代谢和能量供应中的其他有毒副产物，以实现ARD分子机制的详细概述。荧光原位杂交，显微镜，基因表达研究和代谢分析将被用来实现这一目标。比较敏感基因型和不敏感基因型将为早期预测土壤中ARD严重程度的标记提供知识，并将有助于育种计划选择耐ARD的苹果植株。