Department of Plant Science and Landscape Architecture, University of Maryland, College Park, Maryland 20742, USA.
J Food Prot. 2009 Nov;72(11):2321-5. doi: 10.4315/0362-028x-72.11.2321.
Bacterial communities associated with the phyllosphere of apple trees (Malus domestica cv. Enterprise) grown under organic and conventional management were assessed to determine if increased biological food safety risks might be linked with the bacterial communities associated with either treatment. Libraries of 16S rRNA genes were generated from phyllosphere DNA extracted from a wash made from the surfaces of leaves and apples from replicated organic and conventional treatments. 16S rRNA gene libraries were analyzed with software designed to identify statistically significant differences between bacterial communities as well as shared and unique phylotypes. The identified diversity spanned eight bacterial phyla and 14 classes in the pooled organic and conventional libraries. Significant differences between organic and conventional communities were observed at four of six time points (P < 0.05). Despite the identification of significantly diverse microfloras associated with organic and conventional treatments, no detectable differences in the presence of potential enteric pathogens could be associated with either organic or conventional management. Neither of the bacterial genera most commonly associated with produce-related illness outbreaks (Salmonella and Escherichia) was observed in any of the libraries. The impressive bacterial diversity that was documented in this study provides a valuable contribution to our developing understanding of the total microbial ecology associated with the preharvest phyllospheres of food crops. The fact that organic and conventional phyllosphere bacterial communities were significantly different at numerous time points suggests that crop management methods may influence the bacterial consortia associated with the surfaces of fruits and vegetables.
本研究评估了与在有机和常规管理下生长的苹果树（Malus domestica cv. Enterprise）叶际相关的细菌群落，以确定与处理相关的细菌群落是否与增加的生物食品安全风险有关。从叶和苹果表面冲洗液中提取的叶际 DNA 生成了 16S rRNA 基因文库，来自重复的有机和常规处理。使用旨在识别细菌群落之间以及共享和独特的生物型之间具有统计学显着差异的软件分析 16S rRNA 基因文库。鉴定的多样性涵盖了 pooled organic 和 conventional 文库中的 8 个细菌门和 14 个纲。在六个时间点中的四个时间点观察到有机和常规群落之间存在显着差异（P <0.05）。尽管在有机和常规处理中发现了与明显不同的微生物群有关，但与潜在肠道病原体的存在都无法与有机或常规管理联系起来。在任何文库中都没有观察到与与农产品相关的疾病爆发最常相关的细菌属（沙门氏菌和大肠杆菌）。本研究中记录的令人印象深刻的细菌多样性为我们对与食用作物收获前叶际相关的总微生物生态学的不断发展的理解做出了宝贵的贡献。有机和常规叶际细菌群落在许多时间点上显着不同的事实表明，作物管理方法可能会影响与水果和蔬菜表面相关的细菌共生体。
