Microbial community diversities and taxa abundances in soils along a seven-year gradient of potato monoculture using high throughput pyrosequencing approach.
BACKGROUND
Previous studies have focused on linking soil community structure, diversity, or specific taxa to disturbances. Relatively little attention has been directed to crop monoculture soils, particularly potato monoculture. Information about microbial community changes over time between monoculture and non-monoculture treatments is lacking. Furthermore, few studies have examined microbial communities in potato monoculture soils using a high throughput pyrosequencing approach.


RESULTS
Soils along a seven-year gradient of potato monoculture were collected and microbial communities were characterized using high throughput pyrosequencing approach. Principal findings are as follows. First, diversity (H(Shannon)) and richness (S(Chao1)) indices of bacterial community, but not of fungal community, were linearly decreased over time and corresponded to a decline of soil sustainability represented by yield decline and disease incidence increase. Second, Fusarium, the only soilborne pathogen-associated fungal genus substantially detected, was linearly increased over time in abundance and was closely associated with yield decline. Third, Fusarium abundance was negatively correlated with soil organic matter (OM) and total nitrogen (TN) but positively with electrical conductivity (EC). Fourth, Fusarium was correlated in abundances with 6 bacterial taxa over time.


CONCLUSIONS
Soil bacterial and fungal communities exhibited differential responses to the potato monoculture. The overall soil bacterial communities were shaped by potato monoculture. Fusarium was the only soilborne pathogen-associated genus associated with disease incidence increase and yield decline. The changes of soil OM, TN and EC were responsible for Fusarium enrichment, in addition to selections by the monoculture crop. Acidobacteria and Nitrospirae were linearly decreased over time in abundance, corresponding to the decrease of OM, suggesting their similar ecophysiologial trait. Correlations between abundance of Fusarium with several other bacterial taxa suggested their similar behaviors in responses to potato monoculture and/or soil variables, providing insights into the ecological behaviors of these taxa in the environment.
College of Resources and Environmental Sciences, Gansu Agricultural University, Lanzhou, Gansu Province, China ; Gansu Provincial Key Laboratory of Aridland Crop Science, Gansu Agricultural University, Lanzhou, Gansu Province, China.
Xing
X
Liu
College of Agronomy, Gansu Agricultural University, Lanzhou, Gansu Province, China ; Gansu Key Laboratory of Crop Genetic and Germplasm Enhancement, Gansu Agricultural University, Lanzhou, China.
Junlian
J
Zhang
College of Environmental Science and Engineering, Yangzhou University, Yangzhou, Jaingsu Province, China.
Tianyu
T
Gu
College of Resources and Environmental Sciences, Gansu Agricultural University, Lanzhou, Gansu Province, China ; Gansu Provincial Key Laboratory of Aridland Crop Science, Gansu Agricultural University, Lanzhou, Gansu Province, China.
Wenming
W
Zhang
Jiangsu Provincial Key Lab of Organic Solid Waste Utilization, Nanjing Agricultural University, Nanjing, China.
Qirong
Q
Shen
College of Environmental Science and Engineering, Yangzhou University, Yangzhou, Jaingsu Province, China.
Shixue
S
Yin
College of Resources and Environmental Sciences, Gansu Agricultural University, Lanzhou, Gansu Province, China ; Gansu Provincial Key Laboratory of Aridland Crop Science, Gansu Agricultural University, Lanzhou, Gansu Province, China.
Huizhen
H
Qiu
D061271:Acidobacteria / Q000235:genetics; D020561:Alphaproteobacteria / Q000235:genetics; D001203:Ascomycota / Q000235:genetics; D001483:Base Sequence; D001487:Basidiomycota / Q000235:genetics; D018556:Crops, Agricultural / Q000254:growth & development; D004269:DNA, Bacterial / Q000235:genetics; D004271:DNA, Fungal / Q000235:genetics; D005670:Fusarium / Q000235:genetics; D059014:High-Throughput Nucleotide Sequencing; D064307:Microbiota / Q000235:genetics*; D010802:Phylogeny; D012044:Regression Analysis; D017422:Sequence Analysis, DNA; D012988:Soil Microbiology; D011198:Solanum tuberosum / Q000254:growth & development*
D004269:DNA, Bacterial; D004271:DNA, Fungal