Collaborative Research: Molecular, Biochemical and Signal Transduction Analysis of a Phytotoxic Root-Root Communication Process Mediated by (-)-Catechin in the Rhizosphere

合作研究：根际 (-)-儿茶素介导的植物毒性根-根通讯过程的分子、生化和信号转导分析

• 批准号: 0336738
• 负责人: Simon Gilroy
• 金额: $ 25.05万
• 依托单位: Pennsylvania State Univ University Park
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2004
• 资助国家: 美国
• 起止时间: 2004-08-01 至 2007-12-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0336738&HistoricalAwards=false
• 关键词: Collaborative; Research; Molecular; Biochemical; Signal

The soil surrounding a plant root, known as the rhizosphere, is a unique physical, biochemical and ecological environment. The rhizosphere is to a large extent controlled by the root system through chemicals secreted into the surrounding soil. These root secretions (exudates) may play symbiotic or defensive roles as a plant communicates with its environment, ultimately developing a positive or negative response to the other elements in its rhizosphere. An example of negative communication is provided by the Asian native Centaurea maculosa L. (spotted knapweed). Centaurea maculosa Lam. (spotted knapweed) is one of the most invasive and destructive introduced weeds in North America, particularly in the fields and pastures of the northwest U.S. Although it has long been proposed that spotted knapweed achieves its dominance through secretion of a plant-toxic chemical (allelochemical), no such chemical had been identified until last year, when it was determined that an exudate of spotted knapweed roots is indeed toxic to other plants. The active "ingredient" of this chemical is composed of racemic catechin, a 50:50 mixture of (+)-catechin and (-)-catechin. Although (+)-catechin is widespread throughout the plant kingdom, both (-)-catechin and the racemic form are extremely rare. Further, the anti-plant part of the exudate was entirely due to (-)-catechin, while (+)-catechin was inactive. Conversely, (+)-catechin was active against certain bacteria, while (-)-catechin was not. (-)-Catechin was found to be toxic against Arabidopsis and a variety of crop plant species and was also toxic to C. diffusa (diffuse knapweed), a close relative of spotted knapweed. (-)-Catechin did not affect seedlings or seed germination of C. maculosa itself. In Arabidopsis thaliana, spotted knapweed's toxic chemical triggers a rapid cascade of stress responses which kill cells in the root meristem and elongation zone and ultimately lead to the death of the entire root system. The proposed research will shed light on the molecular and biochemical interactions that occur in conjunction with this negative communication process in the subterranean part of this plant. Specifically, the proposal will examine the negative control exerted by (-)-catechin in the rhizosphere of C. maculosa using the following aims: 1) to understand the toxic chemical processes initiated by (-)-catechin in Arabidopsis roots, 2) to understand the mechanism by which C. maculosa detoxifies (-)-catechin, and 3) to clone the gene(s) involved in (-)-catechin production. The interaction of (-)-catechin with plants such as Arabidopsis is an event that occurs under natural soil conditions, and thus has biological relevance. In addition, this research will provide the broader benefits of training two postdoctoral scholars, one graduate student and undergraduates in a multidisciplinary research atmosphere. Furthermore, the research outlined has practical implications to both U.S. agriculture and to preserving plant diversity of the Western U.S.

植物根周围的土壤（称为根际）是一种独特的物理，生化和生态环境。 根际在很大程度上由根系通过分泌到周围土壤中的化学物质控制。 当植物与环境交流时，这些根源分泌物（渗出液）可能起着共生或防御作用，最终对根际中的其他元素产生积极或负面的反应。 亚洲本地Centaurea Maculosa L.（斑点的knapweed）提供了负面通信的一个例子。 Centaurea Maculosa Lam。 （斑质草）是北美最具侵入性，最具破坏性的杂草之一，尤其是在美国西北部的田间和牧场上其他植物。 该化学物质的活性“成分”由消性儿茶素组成，是（+） - 儿茶素和（ - ） - 儿茶素的50:50混合物。 虽然（+） - 儿茶素在整个植物王国中都广泛，但（ - ） - 儿茶素和外星人形式都极为罕见。 此外，渗出液的抗植物部分完全是由于（ - ） - 儿茶素，而（+） - 儿茶素不活跃。相反，（+） - 儿茶素对某些细菌具有活性，而（ - ） - 儿茶素不是。 （ - ） - 儿茶素被发现对拟南芥和各种作物植物物种有毒，也对斑c。diffusa（二型刀草）有毒，这是斑点的刀草的近亲。 （ - ） - 儿茶素不影响麦芽梭菌本身的幼苗或种子发芽。 在拟南芥中，发现了Knapweed的有毒化学化学触发了一系列的压力反应，这些反应杀死了根分生组织和伸长区域中的细胞，并最终导致整个根系的死亡。 拟议的研究将阐明与该植物地下部分的这种负面通信过程结合发生的分子和生化相互作用。 具体而言，该提案将使用以下目的检查（ - ） - 儿茶素在C. maculosa的根圈中施加的负面对照：1）了解拟南芥根中的（ - ） - catechin在Catechin中引发的有毒化学过程，以了解C. Maculosa Detoxifies（ - ） - catechin-catechin和3 catin cline cone cline cotectec。 （ - ） - 儿茶素与拟南芥等植物的相互作用是在自然土壤条件下发生的事件，因此具有生物学相关性。 此外，这项研究将为培训两名博士后学者，一名研究生和本科生在多学科研究氛围中提供更大的好处。 此外，该研究概述对美国农业和维护美国西部的植物多样性具有实际影响