Microbial Diversity Inside Pumpkins: Microhabitat-Specific Communities Display a High Antagonistic Potential Against Phytopathogens
Microbial Diversity Inside Pumpkins: Microhabitat-Specific Communities Display a High Antagonistic Potential Against Phytopathogens
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DOI：
10.1007/s00248-011-9942-4
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发表时间：
2012-02-01
影响因子：
3.6
通讯作者：
Berg, Gabriele
中科院分区：
文献类型：
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作者：
Fuernkranz, Michael;Lukesch, Birgit;Berg, Gabriele
近年来，施蒂里亚油南瓜（Cucurbita pepo L.）亚种佩波湾（styriaca Greb.）主要由子囊菌属真菌Didymellabryphalus引起，但也经常涉及细菌病原体。为探讨南瓜内生菌的生物防治策略，对3个不同南瓜品种的种子（精细胞）、根（根内）、花（花胞）和果实（果胞）中内生菌的多样性进行了研究。采用分子、显微和培养技术相结合的多相方法筛选内生菌生防菌株。通过16 S核糖体RNA基因指纹分析，发现了每个微环境中假单胞菌和芽孢杆菌这两个重要的植物相关属的特定群落结构。所有微环境都以细菌为主;真菌较少。在双重培养试验中分析的2，320个微生物分离株中，165个（7%）在体外对D. bryellow。其中，43株菌株抑制细菌南瓜病原体（胡萝卜果胶杆菌，绿黄假单胞菌，黄单胞菌葫芦）的生长;这里只选择细菌。微环境特异性拮抗剂被发现，和精子圈和花圈被揭示为unexplored水库拮抗剂。在后者中，花粉粒作为花之间的细菌载体的潜在作用被认识到。根据其活性、基因型多样性和发生率选择的六种广谱拮抗剂在温室条件下进行了评价。在南瓜上的病害严重程度为D.通过绿针假单胞菌处理和通过菌株（胶溶杆菌、绿针假单胞菌、多粘类芽孢杆菌和Serratiamuthica）的组合处理，bryophyll显著降低。这一结果为南瓜病害的生物防治提供了良好的前景。
Recent and substantial yield losses of Styrian oil pumpkin (Cucurbita pepo L. subsp. pepo var. styriaca Greb.) are primarily caused by the ascomycetous fungus Didymella bryoniae but bacterial pathogens are frequently involved as well. The diversity of endophytic microbial communities from seeds (spermosphere), roots (endorhiza), flowers (anthosphere), and fruits (carposphere) of three different pumpkin cultivars was studied to develop a biocontrol strategy. A multiphasic approach combining molecular, microscopic, and cultivation techniques was applied to select a consortium of endophytes for biocontrol. Specific community structures for Pseudomonas and Bacillus, two important plant-associated genera, were found for each microenvironment by fingerprinting of 16S ribosomal RNA genes. All microenvironments were dominated by bacteria; fungi were less abundant. Of the 2,320 microbial isolates analyzed in dual culture assays, 165 (7%) were tested positively for in vitro antagonism against D. bryoniae. Out of these, 43 isolates inhibited the growth of bacterial pumpkin pathogens (Pectobacterium carotovorum, Pseudomonas viridiflava, Xanthomonas cucurbitae); here only bacteria were selected. Microenvironment-specific antagonists were found, and the spermosphere and anthosphere were revealed as underexplored reservoirs for antagonists. In the latter, a potential role of pollen grains as bacterial vectors between flowers was recognized. Six broad spectrum antagonists selected according to their activity, genotypic diversity, and occurrence were evaluated under greenhouse conditions. Disease severity on pumpkins of D. bryoniae was significantly reduced by Pseudomonas chlororaphis treatment and by a combined treatment of strains (Lysobacter gummosus, P. chlororaphis, Paenibacillus polymyxa, and Serratia plymuthica). This result provides a promising prospect to biologically control pumpkin diseases.