Comparison of bacterial community structures of terrestrial cyanobacterium Nostoc flagelliforme in three different regions of China using PCR-DGGE analysis
Pei-pei Han1,2 • Shi-gang Shen1 • Shi-ru Jia1 • Hui-yan Wang1 •
Cheng Zhong1 • Zhi-lei Tan1 • He-xin Lv1
Received: 23 December 2014 / Accepted: 13 April 2015 Springer Science+Business Media Dordrecht 2015
Abstract Filamentous Nostoc flagelliforme form colloidal complex, with beaded cells interacting with other bacteria embedded in the complex multilayer sheath.
However, the species of bacteria in the sheath and the interaction between N. flagelliforme and associated bacteria remain unclear. In this study, PCR-denaturing gradient gel electrophoresis (DGGE) was used to investigate the bacterial communities of N. flagelliforme from three regions of
China. DGGE patterns showed variations in all samples, exhibiting 25 discrete bands with various intensities. The diversity index analysis of bands profiles suggested the high similarity of bacterial communities to each other but also the dependence of microbial composition on each location. Phylogenetic affiliation indicated that the majority of the sequences obtained were affiliated with Actinobacteria, Cyanobacteria, Proteobacteria, Acidobacteria, Bacteroidetes, of which Cyanobacteria was dominant, followed the Proteobacteria. Members of the genus Nostoc were the most abundant in all samples. Rhizobiales and
Actinobacteria were identified, whereas, Craurococcus,
Caulobacter, Pseudomonas, Terriglobus and Mucilaginibacter were also identified at low levels. Through comparing the bacterial composition of N. flagelliforme from different regions, it was revealed that N. flagelliforme could facilitate the growth of other microorganisms including both autotrophic bacteria and heterotrophic ones and positively contributed to their harsh ecosystems. The results indicated N. flagelliforme played an important role in diversifying the microbial community composition and had potential application in soil desertification.
Keywords Nostoc flagelliforme Bacterial community composition PCR-DGGE
Desertification, characterized by soil erosion, is one of the most serious environmental and socio-economic problems in many arid and semi-arid areas throughout the world (Gomes et al. 2003). Finding a viable approach to reverse desertification has become an urgent event. Cyanobacteria are the primary producers in the arid environments they inhabit. The ability of these microorganisms to fix nitrogen and fertilize the desert substrates they occupy is important in nutrient-poor desert landscapes. Therefore, the interest arise in light of the important role and multiple functions that cyanobacteria have in arid and semi-arid environments (Bowker et al. 2010; Malam Issa et al. 2006; Mazor et al. 1996; Xie et al. 2007). The strategy of utilization of cyanobacteria to the reconstruction of soil ecosystem function has been widely proposed (Acea et al. 2001;
Bowker 2007; Hu and Liu 2003).
Nostoc flagelliforme, also called ‘Facai’ (hair vegetable) in Chinese, as the result of its hair-like appearance (Fig. 1a), is a terrestrial macroscopic cyanobacterium. It is distributed in arid and semi-arid areas (Fig. 1b), mainly in
Pei-pei Han and Shi-gang Shen have contribute equally to this work. & Shi-ru Jia firstname.lastname@example.org 1 Key Laboratory of Industrial Fermentation Microbiology,
Ministry of Education, School of Biotechnology, Tianjin
University of Science and Technology, Tianjin 300457,
People’s Republic of China 2 Key Laboratory of Systems Bioengineering, Ministry of
Education, Tianjin University, Tianjin 300072,
People’s Republic of China 123
World J Microbiol Biotechnol
Ningxia, Gansu, Qinghai, Inner Mongolia and other provinces in China (Gao and Zou 2001). In the habitats, it shows strong ecological adaptability to extreme conditions such as desiccation, alkali, strong UV radiation, and high temperature (Dodds et al. 1995; Han et al. 2014; Lan et al. 2014; Qian et al. 1989; Qiu and Gao 2001). Because of the good adaptability to the extremes of living conditions, it has been suggested as pioneering desert life. While the overexploitation of N. flagelliforme resources owing to ever-increasing market demand had resulted in serious damage to vegetation in its growing areas and the deterioration of the environment, causing more frequent sandstorms (You 2000). Therefore, N. flagelliforme is an essential part of soil ecosystem and has vital functions on material recycling and energy turnover in ecosystem.
However, the utilization of N. flagelliforme to the reconstruction of soil ecosystem has not been fully explored.
Studying the underlying mechanism would provide significant basis for controlling desertification.
Nostoc flagelliforme is a filamentous cyanobacterium. In the habitats, natural N. flagelliforme form colloidal complex, with beaded cells embedded in the complex multilayer sheaths. It has been reported that beaded cells interacted with many other microorganisms and a large number of bacteria existed in the sheath (Zhu et al. 1998). However, it remains unclear that the species of bacteria in the sheath and the interaction between N. flagelliforme and associated bacteria. Therefore, understanding of the microbial composition of N. flagelliforme is important for knowing the relationship between terrestrial cyanobacteria and associated bacteria, and further helps reveal the role of N. flagelliforme in soil ecosystem. The recently developed molecular biological techniques have made it possible to look into microbial ecology. Denaturing gradient gel electrophoresis (DGGE) of
PCR-amplified genes is not time consuming, low cost, and able to directly determine the nucleotide sequence of bands, and is commonly used to evaluate microorganism diversity (Casserly and Erijman 2003; Ercolini 2004). It has been reported that the environment conditions affect the growth and the distribution of N. flagelliforme (Zhao et al. 2000), so the species of bacteria in the sheath from different regions might be different. In this study, the bacterial community structures of wild N. flagelliforme collected from three different regions of China was investigated by PCR-DGGE.