连作对云南典型烟区植烟土壤细菌群落多样性的影响

为阐明连作对植烟土壤细菌群落的影响,采用MiSeq高通量测序技术对云南省曲靖市、红河州、文山州3个典型烟区连作0、2、4、8年及以上的烟田土壤细菌进行16S rDNA V3～V4区域测序,并结合土壤化学指标分析连作对烟田土壤细菌群落结构的影响.结果 表明:随连作年限的延长,土壤特有细菌数、细菌群落丰度和多样性在曲靖烟区整体呈递增趋势,红河烟区呈递减趋势,文山烟区特有细菌数呈先下降后上升趋势,细菌群落丰度及多样性则呈递增趋势.在门水平上,3个生态产区连作土壤所获得的有效序列涵盖了94.32％～99.31％的细菌类群,放线菌门(Actinobacteria)、变形菌门(Protecobacteria)、绿弯菌门(Chloroflexi)、酸杆菌门(Acidobacteria)、芽单胞菌门(Gemmatimonadetes)、浮霉菌门(Planctomycetes)是主要的优势类群(相对丰度>4.0％),随连作年限的延长,不同生态区优势菌门相对丰度和多样性存在时间和空间异质性.连作植烟土壤pH值、速效钾、有机质、有效磷含量与细菌群落分布显著相关.研究表明,随着连作年限的延长,土壤细菌群落发生不同程度的结构性变化,在连作烟田土壤改良时加强土壤pH值和有效磷含量调控是关键.研究结果为云南典型烟区通过构建差异化的土壤微生物区系和理化环境以消减连作障碍提供了理论依据.

Effects of continuous cropping on tobacco-planting soil bacterial community diversity in typical tobaccogrowing areas of Yunnan Province

This study aimed to clarify the influence of continuous cropping on the tobacco-planting soil bacterial community in typical tobacco-growing areas of Yunnan Province. The V3~V4 region of soil bacterial 16S rDNA was determined using high-throughput MiSeq sequencing and the influence of continuous cropping on abundance and diversity of the soil bacterial community was analyzed in relation to the main chemical characteristics. The results showed that with the extension of continuous cropping duration, the number of endemic bacteria and the abundance and diversity of the bacterial community showed an increasing trend in the Qujing tobacco-growing area, whereas the Honghe tobacco-growing area showed an decreasing trend. The number of endemic bacteria in the Wenshan tobacco-growing area first showed a decreasing trend and subsequently, an increasing trend, whereas the abundance and diversity of the bacterial community showed an increasing trend. At the phylum level, the effective sequences obtained from continuous cropping soils in the three tobacco-growing ecological areas showed 94.32%~99.31% sequence identity to the bacterial groups Actinobacteria, Proteobacteria, Chloroflexi, Acidobacteria, Gemmatimonadetes, and Planctomycetes, which were the dominant community groups(relative abundance>4.0%). The abundance and diversity of the dominant phylum were spatially and temporally heterogeneous in different ecozones with the extension of continuous cropping duration. Soil pH and available K, organic matter, and available P content were significantly correlated with bacterial community distribution in the continuous cropping soil. The results provide a theoretical basis for reducing challenges owing to continuous cropping by revealing the differences in soil microflora and physical and chemical environment in typical tobacco-growing areas of Yunnan Province.