干旱半干旱区果园生草条件下土壤微生物(细菌)的多样性

Diversity of Soil Microorganisms(Bacteria)Under Herbaceous Conditions in Orchards in Arid and Semi-arid Areas

采选4种具备潜在“绿肥”功能的草种(黑麦草、苜蓿、高羊茅、长柔毛野豌豆)以及自然生草和清耕模式进行果园行间长期生草处理,应用高通量测序技术分析不同生草模式下果园土壤细菌群落结构、数量和功能的变化,以期为干旱半干旱区果园的合理生草和苹果生产可持续发展提供参考依据。结果表明:生草处理下细菌OTUs被划分为39个已知细菌门、94纲、266目、541科、127属。其中苜蓿(458个OTUs)及自然生草(531个OTUs)处理具有更多的群体特异性OTUs,其次为黑麦草与长柔毛野豌豆处理,并且相较于清耕,生草处理的土壤显著富集了拟杆菌纲、梭状芽孢杆菌纲、放线菌纲、变形菌纲、拟杆菌门、草酸杆菌科、假单胞菌科、芽孢杆菌科等有益微生物。PCoA主成分、Adonis组间差异分析和α多样性(ACE指数)进一步表明,土壤细菌群落的组成主要受生草处理影响,其中自然生草、苜蓿及长柔毛野豌豆处理区域土壤样品中的细菌群落差异以及细菌多样性更显著。同时自然生草、苜蓿及长柔毛野豌豆生草处理下差异代谢通路主要聚焦于碳水化合物代谢,氨基酸代谢,能量代谢,跨膜转运及核苷酸代谢,其平均丰度分别为13.6%、9.5%、4.2%、3.4%、3.2%。综上所述,生草处理可影响细菌群落结构,其中自然生草、苜蓿及长柔毛野豌豆生草进一步显著促进了细菌群落的功能。

Four grass species(ryegrass,alfalfa,tall fescue,villous wild pea)with the potential for‘green fertilizer’function were selected,and natural grassing and clean-tillage modes were carried out long-term grassing treatment in the orchard rows,and high-throughput sequencing technology was applied to analyze the changes in the structure,quantity,and function of the soil bacterial community in the orchard under different grassing modes,in order to provide a reference for the rational grassing of orchards and the sustainable development of apple production in arid and semi-arid zones.The results showed that,the bacterial OTUs under the grassing treatment were categorized into 39 known bacterial phyla,94 orders,266 orders,541 families and 127 genera.Among them,alfalfa(458 OTUs)and natural grassing(531 OTUs)had more population-specific OTUs,followed by ryegrass and villous wild pea treatments,and the soil of the grassing treatment was significantly enriched with beneficial microorganisms such as Bacteroidetes,Clostridia,Actinobacteria,Ascomycetes,Bacteriophage,Oxalobacteria,Pseudomonas,and Bacteroides,in comparison with clean-tillage.PCoA principal components,Adonis intergroup analysis of variance(AOVA),and alpha diversity(ACE index)further indicated that the composition of soil bacterial communities was mainly affected by the raw grass treatments,with the differences in bacterial communities as well as bacterial diversity in soil samples from natural grassing,alfalfa,and villous wild pea treatment areas being more significant.In addition,the differential metabolic pathways under natural grass,alfalfa and villous wild pea grass treatments mainly focused on carbohydrate metabolism,amino acid metabolism,energy metabolism,transmembrane transport,and nucleotide metabolism,with average abundances of 13.6%,9.5%,4.2%,3.4%,and 3.2%,respectively.In summary,the grassing treatment could affect the bacterial community structure,which the natural grassing,alfalfa,and villous wild pea haying further significantly contributed to the function of the bacterial community.