三岔湖沉积物中葡萄糖脱氢酶gcd基因的多样性及其与环境因子的关系

为了研究沉积物中葡萄糖脱氢酶gcd基因多样性及其与环境因子的关系，揭示对水体富营养化有重要影响的微生物类群，分别于2017年的春季和秋季对三岔湖沉积物及其表层上覆水采样，对沉积物基因组DNA的gcd基因进行高通量测序，分析gcd基因多样性和群落结构特征，探讨其与环境因子之间的关系.结果表明:①12个样品共得到219 778条有效序列，分属于6门、9纲、15目、29科、46属、610个OTUs，主要来源于变形菌门（25.10%~98.85%）、酸杆菌门（0~3.99%）.②gcd基因序列系统发育树分为两支，四亚支，基因序列主要归属于根瘤菌目、伯克氏菌目、海洋螺菌目、假单胞菌目、酸杆菌目.③gcd基因的生物多样性大小为春季>秋季，湖中心>湖坝>湖尾；在gcd基因细菌群落组成上，季节性变化对L1、L2、L3、L5采样点影响较小，而对L4和L6采样点影响较大.④gcd基因的生物多样性与ρ（DO）、w（TP）、w（HCl-P）、ρ（DTP）显著相关，gcd基因的OTU组成和分布与ρ（DO）、ρ（DTP）显著相关.研究显示，三岔湖水体沉积物中的gcd基因具有较高的生物多样性，组成和分布呈现异质性，对ρ（DTP）具有重要影响作用. 

Diversity of Glucose Dehydrogenase gcd Gene and Its Relationship with Environmental Factors in Sediment of Sancha Lake

The sediment and overlying water of Sancha Lake were collected in the spring and autumn of 2017 to study the diversity of glucose dehydrogenase gcd gene and its relationship with environmental factors. High-throughput sequencing of gcd gene from the genomic DNA in the sediments was carried out to evaluate the diversity in gcd and associated community characteristics and to analyse the correlations between the gcd gene diversity indices and environmental factors. The results showed that:(1) from the 12 samples, 219, 778 valid sequences were obtained, and the classification annotation suggests 6 Phyla, 9 Classes, 15 Orders, 29 Families, 46 Genera, and 610 operational taxonomic units (OTUs), primarily Proteobacteria (25.10%-98.85%) and Acidobacteria (0-3.99%). (2) The phylogenetic tree of gcd gene sequences exhibits two branches and four sub-branches, and the gene sequences primarily attributed to orders Rhizobiales, Burkholderiales, Oceanospirillales, Pseudomonadales, and Acidobacteriales. (3) The gcd gene diversity were all higher in spring than in autumn, increasing from the lake center to the dam to the lake tail. In terms of the community composition of gcd-harboring bacteria, seasonal variation had a small effect on sampling sites L1, L2, L3, and L5, but had an appreciable impact on the sites L4 and L6. (4) The diversity indices of gcd gene were significantly correlated with ρ(DO), w(TP), w(HCl-P), and ρ(DTP). The OTU composition and distribution of gcd gene were significantly correlated with ρ(DO) and ρ(DTP). Our study indicated that the gcd gene in the sediment of Sancha Lake is highly diverse, with heterogeneous composition and distribution, which had great effect on ρ(DTP).