Changes in the phyllosphere community of the resurrection fern, Polypodium polypodioides, associated with rainfall and wetting
Changes in the phyllosphere community of the resurrection fern, Polypodium polypodioides, associated with rainfall and wetting
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DOI：
10.1111/j.1574-6941.2006.00152.x
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发表时间：
2006-11-01
影响因子：
4.2
通讯作者：
Jackson, Colin R.
中科院分区：
文献类型：
--
作者：
Jackson, Evelyn F.;Echlin, Haley L.;Jackson, Colin R.
结合分析被用来描述附生复活蕨类植物水龙骨叶圈内细菌群落发生的变化，因为蕨类植物从耐干燥、生理上不活跃的状态复水。浓缩分析表明，在降雨后，使用不稳定的有机底物的细菌活数量增加。培养得到的菌株主要是革兰氏阳性细菌，隶属于放线杆菌和菲米库特的不同类群。相反，对从整个群落DNA中获得的16S rRNA基因克隆的测序表明，该群落的大部分由其他分类群主导，特别是阿尔法变形杆菌。从干的和水合的水龙骨叶中都获得了相似的分离株，而群落DNA的16S rRNA基因测序显示，干的和湿的蕨类植物上的核糖体类型不同，湿润后丰富度总体下降。湿润还引起叶球胞外酶活性的变化，最初的活性在降雨后突然爆发，随后在大约48小时后突然爆发。这些发现表明，复活蕨类植物拥有一个复杂的叶圈群落，降雨后蕨类植物的复水作用可能是一种富含细菌的培养物，刺激了某些细菌种群，并改变了整个群落的结构和活动。
A combination of analyses were used to characterize the changes that occur in a bacterial community present in the phyllosphere of the epiphytic resurrection fern, Polypodium polypodioides, as the fern rehydrates from a desiccation-resistant, physiologically inactive state. Enrichment assays showed an increase in the viable count of bacteria using labile organic substrates following rainfall. Isolates obtained from enrichments were predominantly Gram-positive bacteria affiliated with various groups of the Actinobacteria and Firmicutes. In contrast, sequencing of 16S rRNA genes clones obtained from whole community DNA revealed that much of the community was dominated by other taxa, particularly the Alphaproteobacteria. Similar isolates were obtained from both dry and hydrated P. polypodioides fronds, whereas 16S rRNA gene sequencing of community DNA revealed different ribotypes on the dry and wet fern, and an overall reduction in richness following wetting. Wetting also produced changes in phyllosphere extracellular enzyme activity, with an initial burst of activity following rainfall and a subsequent burst approximately 48 h later. These findings suggest that the resurrection fern harbors a complex phyllosphere community, and that rehydration of the fern following rainfall may act as an enrichment culture stimulating certain bacterial populations and changing the overall community structure and activity.