Valverde Angel, De Maayer Pieter, Oberholster Tanzelle, Henschel Joh, Louw Michele K, Cowan Don
Department of Genetics, Centre for Microbial Ecology and Genomics, University of Pretoria, Pretoria, South Africa.
Namib Ecological Restoration and Monitoring Unit, Gobabeb Research and Training Centre, Walvis Bay, Namibia.
PLoS One. 2016 Apr 11;11(4):e0153353. doi: 10.1371/journal.pone.0153353. eCollection 2016.
Welwitschia mirabilis is an ancient and rare plant distributed along the western coast of Namibia and Angola. Several aspects of Welwitschia biology and ecology have been investigated, but very little is known about the microbial communities associated with this plant. This study reports on the bacterial and fungal communities inhabiting the rhizosphere of W. mirabilis and the surrounding bulk soil. Rhizosphere communities were dominated by sequences of Alphaproteobacteria and Euromycetes, while Actinobacteria, Alphaproteobacteria, and fungi of the class Dothideomycetes jointly dominated bulk soil communities. Although microbial communities within the rhizosphere and soil samples were highly variable, very few "species" (OTUs defined at a 97% identity cut-off) were shared between these two environments. There was a small 'core' rhizosphere bacterial community (formed by Nitratireductor, Steroidobacter, Pseudonocardia and three Phylobacteriaceae) that together with Rhizophagus, an arbuscular mycorrhizal fungus, and other putative plant growth-promoting microbes may interact synergistically to promote Welwitschia growth.
百岁兰是一种古老而珍稀的植物，分布于纳米比亚和安哥拉的西海岸。人们已经对百岁兰的生物学和生态学的几个方面进行了研究，但对于与这种植物相关的微生物群落却知之甚少。本研究报告了栖息在百岁兰根际及其周围大块土壤中的细菌和真菌群落。根际群落以α-变形菌纲和座囊菌纲的序列为主，而放线菌、α-变形菌纲和座囊菌纲的真菌共同主导了大块土壤群落。尽管根际和土壤样品中的微生物群落高度可变，但这两种环境之间共享的“物种”（以97%的同一性阈值定义的操作分类单元）却很少。有一个小型的“核心”根际细菌群落（由硝酸盐还原菌属、类固醇杆菌属、假诺卡氏菌属和三个根瘤菌科组成），它与丛枝菌根真菌根内球囊霉以及其他假定的促进植物生长的微生物可能协同相互作用，以促进百岁兰的生长。
