Biodegradation of the Allelopathic Chemical Pterostilbene by a Sphingobium sp. Strain from the Peanut Rhizosphere
Biodegradation of the Allelopathic Chemical Pterostilbene by a Sphingobium sp. Strain from the Peanut Rhizosphere
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DOI：
10.1128/aem.02154-18
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发表时间：
2018-12
影响因子：
4.4
通讯作者：
R. Yu;Zohre Kurt;F. He;J. Spain
中科院分区：
文献类型：
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作者：
R. Yu;Zohre Kurt;F. He;J. Spain
蕨类化合物是白藜芦醇的类似物，是植物产生的一种抑制微生物感染的二苯乙烯类化感物质。作为一种有效的抗氧化剂，蕨类化合物的抗真菌作用比白藜芦醇更有效。这种植物天然产物的细菌降解会影响蕨类化合物的化感作用和去向，从而影响其生态作用。本研究探索了花生组织和根际中降解白藜芦醇和蕨类化合物的细菌的分离和丰度，蕨类化合物的分解代谢途径，以及蕨类化合物最初裂解的分子基础。如果植物化感作用是农业和入侵植物管理中的一个重要过程，那么降解化感作用化学物质的细菌的生态作用也必须同样重要。摘要许多植物产生化感物质，如二苯乙烯类化合物，以抑制病原真菌。与植物相关的细菌对化感物质的降解将限制它们的有效性，但人们对生物降解的程度或涉及的细菌知之甚少。对花生(花生)植物的组织和根际环境的筛选显示，能够在白藜芦醇和蕨类化合物上生长的细菌大量丰富，这是花生植物产生的最常见的二苯乙烯类化合物。狮身人掌分解代谢途径的研究。从根际分离的菌株JS1018表明，类胡萝卜素裂解加氧酶(CCO)能催化蕨类化合物的初始裂解，导致4-羟基苯甲醛和3，5-二甲氧基苯甲醛的瞬时积累。4-羟基苯甲醛用于该菌株的生长，3，5-二甲氧基苯甲醛进一步转化为相对分子质量为414的末端代谢物(C24H31O6)。在JS1018菌株基因组中发现了编码初始加氧酶的基因，并在大肠杆菌中进行了异源表达，证实了该基因的功能。本研究揭示了植物伴生细菌对蕨类化合物的生物降解途径。这种细菌在根际和植物组织中的流行表明细菌干扰在植物化感作用中的潜在作用。重要的蕨类化合物是白藜芦醇的类似物，是一种由植物产生的抑制微生物感染的二苯乙烯类化感物质。作为一种有效的抗氧化剂，蕨类化合物的抗真菌作用比白藜芦醇更有效。这种植物天然产物的细菌降解会影响蕨类化合物的化感作用和去向，从而影响其生态作用。本研究探索了花生组织和根际中降解白藜芦醇和蕨类化合物的细菌的分离和丰度，蕨类化合物的分解代谢途径，以及蕨类化合物最初裂解的分子基础。如果植物化感作用是农业和入侵植物管理中的一个重要过程，那么降解化感作用化学物质的细菌的生态作用也必须同样重要。
Pterostilbene, an analog of resveratrol, is a stilbene allelochemical produced by plants to inhibit microbial infection. As a potent antioxidant, pterostilbene acts more effectively than resveratrol as an antifungal agent. Bacterial degradation of this plant natural product would affect the allelopathic efficacy and fate of pterostilbene and thus its ecological role. This study explores the isolation and abundance of bacteria that degrade resveratrol and pterostilbene in peanut tissues and rhizosphere, the catabolic pathway for pterostilbene, and the molecular basis for the initial cleavage of pterostilbene. If plant allelopathy is an important process in agriculture and management of invasive plants, the ecological role of bacteria that degrade the allelopathic chemicals must be equally important. ABSTRACT Many plants produce allelopathic chemicals, such as stilbenes, to inhibit pathogenic fungi. The degradation of allelopathic compounds by bacteria associated with the plants would limit their effectiveness, but little is known about the extent of biodegradation or the bacteria involved. Screening of tissues and rhizosphere of peanut (Arachis hypogaea) plants revealed substantial enrichment of bacteria able to grow on resveratrol and pterostilbene, the most common stilbenes produced by the plants. Investigation of the catabolic pathway in Sphingobium sp. strain JS1018, isolated from the rhizosphere, indicated that the initial cleavage of pterostilbene was catalyzed by a carotenoid cleavage oxygenase (CCO), which led to the transient accumulation of 4-hydroxybenzaldehyde and 3,5-dimethoxybenzaldehyde. 4-Hydroxybenzaldehyde was subsequently used for the growth of the isolate, while 3,5-dimethoxybenzaldehyde was further converted to a dead-end metabolite with a molecular weight of 414 (C24H31O6). The gene that encodes the initial oxygenase was identified in the genome of strain JS1018, and its function was confirmed by heterologous expression in Escherichia coli. This study reveals the biodegradation pathway of pterostilbene by plant-associated bacteria. The prevalence of such bacteria in the rhizosphere and plant tissues suggests a potential role of bacterial interference in plant allelopathy. IMPORTANCE Pterostilbene, an analog of resveratrol, is a stilbene allelochemical produced by plants to inhibit microbial infection. As a potent antioxidant, pterostilbene acts more effectively than resveratrol as an antifungal agent. Bacterial degradation of this plant natural product would affect the allelopathic efficacy and fate of pterostilbene and thus its ecological role. This study explores the isolation and abundance of bacteria that degrade resveratrol and pterostilbene in peanut tissues and rhizosphere, the catabolic pathway for pterostilbene, and the molecular basis for the initial cleavage of pterostilbene. If plant allelopathy is an important process in agriculture and management of invasive plants, the ecological role of bacteria that degrade the allelopathic chemicals must be equally important.