Gros Raphaël, Jocteur Monrozier Lucile, Faivre Pierre
Institut Méditerranéen d'Ecologie et de Paléoécologie (UMR CNRS 6116), Faculté des Sciences et Techniques de St Jérôme, Université Paul Cézanne, Avenue Escadrille Normandie-Niemen, 13397 Marseille Cedex 20, France.
Environ Microbiol. 2006 Nov;8(11):1889-901. doi: 10.1111/j.1462-2920.2006.01106.x.
Responses of bacterial communities to disturbance and restoration processes were investigated on alpine grassland soil. Bulk soil, rhizosphere soil and two soil separates, i.e. sand-size (2000-200 microm) and silt-size (50-2 microm) were sampled from undisturbed grassland soil to soil under restoration for 1 month, 1 year, 4 years and 13 years after disturbance. Automated ribosomal intergenic spacer analysis (ARISA) and restriction fragment length polymorphism (RFLP) of nifH gene pools were used to assay genetic structure of the bacterial communities and N2-fixing guild. According to the distribution of ARISA band length in bacterial phyla, the dominance of ARISA bands below 400 bp showed that Gram-positive bacteria would be predominant in the studied grassland soil when not disturbed. Disturbance affected the genetic structure of bacterial community and of N2-fixing guild in relation to their location within the selected habitats. Shifts in IGS and nifH profiles of bulk soil metagenome were larger than those observed from sand-size- and silt-size-fractions, accounting for 40-50% of the variance in the profiles. Restoration of the genetic structure of telluric bacteria community and N2-fixing populations was found to be influenced by the spatial heterogeneity of the soil and niche diversification. Particular bacterial genetic structure within distinct habitats were evidenced and must be defined as subdivisions of the meta-community of bulk soil. Scale of soil microbial diversity/stability relationships is discussed with special attention to disconnected bacterial habitat compared with whole soil with multiple niches.
我们研究了高山草原土壤中细菌群落对干扰和恢复过程的响应。从未受干扰的草原土壤到干扰后恢复1个月、1年、4年和13年的土壤，采集了原状土、根际土以及两种土壤粒级，即砂粒级（2000 - 200微米）和粉粒级（50 - 2微米）的土壤样本。利用自动核糖体基因间隔区分析（ARISA）和nifH基因库的限制性片段长度多态性（RFLP）来分析细菌群落和固氮菌群体的遗传结构。根据细菌门类中ARISA条带长度的分布，400 bp以下的ARISA条带占优势表明，在未受干扰的情况下，革兰氏阳性菌在研究的草原土壤中占主导地位。干扰影响了细菌群落和固氮菌群体的遗传结构，这与它们在所选生境中的位置有关。原状土宏基因组的IGS和nifH图谱变化大于砂粒级和粉粒级部分，占图谱变异的40 - 50%。发现陆生细菌群落和固氮种群遗传结构的恢复受土壤空间异质性和生态位多样化的影响。不同生境中特定的细菌遗传结构得到了证实，必须将其定义为原状土元群落的细分。我们讨论了土壤微生物多样性/稳定性关系的尺度，特别关注与具有多个生态位的整个土壤相比，不连续的细菌生境。
