5种石灰岩特有植物根际土壤细菌群落特征和功能研究

Rhizosphere Bacterial Community Characteristics and Function of Five Limestone Endemic Plants

摘要:

为了解不同石灰岩特有植物根际土壤细菌群落的共性和差异，通过16S rDNA高通量测序和生物信息学方法，以分析5种广东石灰岩特有植物大桥虎耳草(Saxifraga daqiaoensis)、癞叶秋海棠(Begonia leprosa)、淡黄报春苣苔(Primulina alutacea)、多莛报春苣苔(P. polycephala)和阳山报春苣苔(P. yangshanensis)根际土细菌群落特征和功能。结果表明，5种植物根际土中共检测到细菌42门113纲250目315科498属，其中绿弯菌门(Chloroflexi)、拟杆菌门(Bacteroidetes)、放线菌门(Actinobacteria)、浮霉菌门(Planctomycetes)、变形菌门(Proteobacteria)和酸杆菌门(Acidobacteria)在5种植物根际土细菌群落中占绝对优势。速效磷、交换性钙、碱解氮、有机质、pH和全氮是影响细菌群落组成的主要因子。不同植物富集了不同的细菌类群，癞叶秋海棠的根际细菌群落结构组成与其他4种植物存在明显差异，根际细菌功能也存在差异。PICRUSt2功能预测表明5种植物根际细菌群落在新陈代谢功能方面最活跃，FAPROTAX功能预测表明化能异养型、好氧化能异养型、硝化作用型和好氧氨氧化型细菌是5种植物根际中共同的优势功能类群，对植物生长具有重要作用。这可为石灰岩特有植物引种驯化提供土壤微环境数据。

Abstract:

To understand the similarities and differences in the rhizosphere bacterial communities of different limestone endemic plants, five species of limestone endemic plants in northern Guangdong were studied, including Saxifraga daqiaoensis, Begonia leprosa, Primulina alutacea, P. polycephala and P. yangshanensis. The rhizosphere bacterial community characteristics and functional component of five limestone endemic plants were analysed by using high-throughput 16S rDNA sequencing and bioinformatics methods. The results showed that 42 phyla, 113 classes, 250 orders, 315 families, and 498 genera bacteria were detected in rhizosphere soil of five plants. Chloroflexi, Bacteroidetes, Actinobacteria, Planctomycetes, Proteobacteria and Acidobacteria were the dominant phyla. Heatmap analysis indicated that the soil physical and chemical factors, including available phosphorus, exchangeable calcium, ammonium nitrogen, soil organic matter, pondus hydrogenii and total nitrogen, played important roles in the composition of bacterial community. The LEfSe analysis showed that different plants enriched different rhizosphere bacterial population. The composition and function of the rhizosphere bacterial community of B. leprosa was significantly different from those of the other four plants. The prediction of PICRUSt2 function showed that the rhizosphere bacterial communities of five plants were the most active in metabolism. The function prediction of FARPOTAX showed that chemoheterotrophy, aerobic chemoheterotrophy, nitrification and aerobic ammonia oxidation were the common dominant functional population in the rhizosphere bacteria of five plants. These functional bacteria play an important role in helping plants grow and develop. It would provide soil microenvironment data for the introduction and domestication of endemic plants in limestone.