长期施用氮肥和磷肥对渭北旱塬土壤中氨氧化古菌多样性的影响

采用基于氨单加氧酶基因的PCR-RFLP和DNA测序技术,以黄土高原旱地黑垆土为材料,研究长期施用氮肥和磷肥对土壤氨氧化古菌多样性的影响.结果显示,不同施肥处理土壤样品得到的氨氧化古菌的OTU数分别为25(种植不施肥,CK)、21(不施肥不种植,LD)、18(单施氮肥,N)、25(单施磷肥,P)和13(氮、磷共施,NP).氨氧化古菌的多样性指数H′和优势度指数Ds变化趋势基本相同,分别为P＞CK＞LD＞NP＞N和P＞CK＞NP＞LD＞N;种群丰富度和均匀度指数在不同处理间变化较大,分别为CK＞P＞LD＞N＞NP和P＞NP＞LD＞N＞CK.各处理优势氨氧化古菌绝大部分属于Cluster S,少数属于Cluster M,获得的序列全部属于难培养泉古菌门.不同施肥方式的长期定位试验土壤中氨氧化古菌多样性变化较大,而优势氨氧化古菌系统进化定位没有显著变化.

Effects of Long-term Nitrogen and Phosphate Fertilization on Diversity of Ammonia-Oxidizing Archaea in Dry Highland Soil of Loess Plateau, China

Ammonia-oxidizing archaea are likely the most abundant ammonia-oxidizing microbes in natural environment and they also play an important role in nitrification.In order to improve nitrogen use efficiency and explicate the indicating function of ammonia-oxidizing archaea(AOA) on changes of soil quality in the Loess Plateau,AOA community structure diversity was studied.The soil samples used in this research derived from Changwu Agro-ecological Experimental Station on the Loess Plateau,Chinese Academy of Sciences,which had received 23 years continuous fertilization treatments,include CK(control,without fertilizers),LD(unplanted,without fertilizers),N(nitrogen input),P(phosphorus input) and NP(combination of nitrogen and phosphorus fertilizers).The soil AOA community structure diversity was analyzed by restriction fragment length polymorphism(PCR-RFLP) and DNA sequence.Positive clones collected randomly from clone libraries were digested by Rsa I and Msp I,respectively.According to the statistics of diversity index,there were 25,18,29,20 and 30 restriction endonuclease types(OTUs),respectively.The α diversity indices indicated that there was a pronounced difference among five fertilizer treatments.The OTUs were the highest in both P treatment and CK treatment,while the lowest in NP treatment.The rescaled distance matrix tree indicated that the different fertilization had weak convergence of AOA community types with the CK treatment soil.Phylogenetic tree of amoA gene amino acid sequences analysis showed all AOA sequences fell within cluster S and cluster M,but the proportions were different.These results indicated that long-term fertilization resulted in change of AOA community diversity;however,different fertilizer alkaline soil had no significant impact on the species composition of dominant AOA.