An antibiotic complex from Lysobacter enzymogenes strain C3:: Antimicrobial activity and role in plant disease control
An antibiotic complex from Lysobacter enzymogenes strain C3:: Antimicrobial activity and role in plant disease control
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DOI：
10.1094/phyto-98-6-0695
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发表时间：
2008-06-01
期刊：
影响因子：
3.2
通讯作者：
Yuen, G. Y.
中科院分区：
文献类型：
--
作者：
Li, S.;Jochum, C. C.;Yuen, G. Y.
溶酶杆菌C3是一种细菌生物防治剂，对多种真菌病原体具有拮抗作用。其抗真菌活性部分归因于裂解酶。在本研究中，发现了一种热稳定抗真菌因子（HSAF），一种由二氢麦芽酚素和结构相关的大环内酰胺组成的抗生素复合物，负责C3对真菌和卵菌的拮抗。纯化后的HSAF在体外对多种真菌和卵菌表现出抑制活性，抑制孢子萌发，并破坏敏感真菌的菌丝极性。高羊茅叶片部分纯化后，25 μ g/ml及以上浓度的HSAF与对照相比抑制了双极莲分生孢子的萌发。施用12.5 μ g/ml的HSAF虽然没有降低分生孢子的萌发率，但抑制了附着胞的形成，抑制了两极叶斑病的发生。以高羊茅双极叶斑病和小麦赤霉病的生物防治效果为对照，比较了2个突变株C3 （K19和Delta NRPS）合成HSAF的多酮合成酶-非核糖体肽合成酶基因在不同区域被破坏而丧失了产生HSAF的能力。与C3相比，两种突变株降低双极叶斑病发病率和严重程度的能力均有所下降。相反，突变菌株在降低赤霉病的严重程度方面与野生型菌株一样有效。因此，HSAF似乎是C3菌株对一些（但不是全部）植物病原真菌进行生物控制的机制。
Lysobacter enzymogenes C3 is a bacterial biological control agent that exhibits antagonism against multiple fungal pathogens. Its antifungal activity was attributed in part to lytic enzymes. In this study, a heat-stable antifungal factor (HSAF), an antibiotic complex consisting of dihydromaltophilin and structurally related macrocyclic lactams, was found to be responsible for antagonism by C3 against fungi and oomycetes in culture. HSAF in purified form exhibited inhibitory activity against a wide range of fungal and oomycetes species in vitro, inhibiting spore germination, and disrupting hyphal polarity in sensitive fungi. When applied to tall fescue leaves as a partially-purified extract, HSAF at 25 mu g/ml and higher inhibited germination of conidia of Bipolaris sorokiniana compared with the control. Although application of HSAF at 12.5 mu g/ml did not reduce the incidence of conidial germination, it inhibited appressorium formation and suppressed Bipolaris leaf spot development. Two mutant strains of C3 (K19 and Delta NRPS) that were disrupted in different domains in the hybrid polyketide synthase-nonribosomal peptide synthetase gene for HSAF biosynthesis and had lost the ability to produce HSAF were compared with the wild-type strain for biological control efficacy against Bipolaris leaf spot on tall fescue and Fusarium head blight, caused by Fusarium graminearum, on wheat. Both mutant strains exhibited decreased capacity to reduce the incidence and severity of Bipolaris leaf spot compared with C3. In contrast, the mutant strains were as efficacious as the wild-type strain in reducing the severity of Fusarium head blight. Thus, HSAF appears to be a mechanism for biological control by strain C3 against some, but not all, plant pathogenic fungi.