scholarly journals Effects of Different 3-Year Cropping Systems on Soil Microbial Communities and Rhizoctonia Diseases of Potato

2006 ◽  
Vol 96 (1) ◽  
pp. 68-79 ◽  
Author(s):  
Robert P. Larkin ◽  
C. Wayne Honeycutt
Keyword(s):  
Fatty Acid ◽  
Microbial Communities ◽  
Sweet Corn ◽  
Cropping Systems ◽  
Soil Microbial Communities ◽  
Microbial Populations ◽  
Culturable Bacteria ◽  
Soil Microbial ◽  
Entry Points ◽  
Potato Crops

Eight different 3-year cropping systems, consisting of soybean-canola, soybean-barley, sweet corn-canola, sweet corn-soybean, green bean-sweet corn, canola-sweet corn, barley-clover, and continuous potato (non-rotation control) followed by potato as the third crop in all systems, were established in replicated field plots with two rotation entry points in Presque Isle, ME, in 1998. Cropping system effects on soil microbial community characteristics based on culturable soil microbial populations, single carbon source substrate utilization (SU) profiles, and whole-soil fatty acid methyl ester (FAME) profiles were evaluated in association with the development of soilborne diseases of potato in the 2000 and 2001 field seasons. Soil populations of culturable bacteria and overall microbial activity were highest following barley, canola, and sweet corn crops, and lowest following continuous potato. The SU profiles derived from BIOLOG ECO plates indicated higher substrate richness and diversity and greater utilization of certain carbohydrates, carboxylic acids, and amino acids associated with barley, canola, and some sweet corn rotations, indicating distinct differences in functional attributes of microbial communities among cropping systems. Soil FAME profiles also demonstrated distinct differences among cropping systems in their relative composition of fatty acid types and classes, representing structural attributes of microbial communities. Fatty acids most responsible for differentiation among cropping systems included 12:0, 16:1 ω5c, 16:1 ω7c, 18:1 ω9c, and 18:2ω6c. Based on FAME biomarkers, barley rotations resulted in higher fungi-to-bacteria ratios, sweet corn resulted in greater mycorrhizae populations, and continuous potato produced the lowest amounts of these and other biomarker traits. Incidence and severity of stem and stolon canker and black scurf of potato, caused by Rhizoctonia solani, were reduced for most rotations relative to the continuous potato control. Potato crops following canola, barley, or sweet corn provided the lowest levels of Rhizoctonia disease and best tuber quality, whereas potato crops following clover or soybean resulted in disease problems in some years. Both rotation crop and cropping sequence were important in shaping the microbial characteristics, soilborne disease, and tuber qualities. Several microbial parameters, including microbial populations and SU and FAME profile characteristics, were correlated with potato disease or yield measurements in one or both harvest years. In this study, we have demonstrated distinctive effects of specific rotation crops and cropping sequences on microbial communities and have begun to relate the implications of these changes to crop health and productivity.

scholarly journals Continuous monocropping highly affect the composition and diversity of microbial communities in peanut (Arachis hypogaea L.)

2021 ◽  
Vol 49 (4) ◽  
pp. 12532
Author(s):  
Ali I. MALLANO ◽  
Xianli ZHAO ◽  
Yanling SUN ◽  
Guangpin JIANG ◽  
Huang CHAO
Keyword(s):  
Microbial Communities ◽  
Management Practices ◽  
Rhizosphere Soil ◽  
Diversity Index ◽  
Cropping Systems ◽  
Soil Microbial Communities ◽  
Pathogenic Fungi ◽  
Continuous Cropping ◽  
Bacterial Phyla ◽  
Soil Microbial

Continuous cropping systems are the leading cause of decreased soil biological environments in terms of unstable microbial population and diversity index. Nonetheless, their responses to consecutive peanut monocropping cycles have not been thoroughly investigated. In this study, the structure and abundance of microbial communities were characterized using pyrosequencing-based approach in peanut monocropping cycles for three consecutive years. The results showed that continuous peanut cultivation led to a substantial decrease in soil microbial abundance and diversity from initial cropping cycle (T1) to later cropping cycle (T3). Peanut rhizosphere soil had Actinobacteria, Protobacteria, and Gemmatimonadetes as the major bacterial phyla. Ascomycota, Basidiomycota were the major fungal phylum, while Crenarchaeota and Euryarchaeota were the most dominant phyla of archaea. Several bacterial, fungal and archaeal taxa were significantly changed in abundance under continuous peanut cultivation. Bacterial orders, Actinomycetales, Rhodospirillales and Sphingomonadales showed decreasing trends from T1>T2>T3. While, pathogenic fungi Phoma was increased and beneficial fungal taxa Glomeraceae decreased under continuous monocropping. Moreover, Archaeal order Nitrososphaerales observed less abundant in first two cycles (T1&T2), however, it increased in third cycle (T3), whereas, Thermoplasmata exhibit decreased trends throughout consecutive monocropping. Taken together, we have shown the taxonomic profiles of peanut rhizosphere communities that were affected by continuous peanut monocropping. The results obtained from this study pave ways towards a better understanding of the peanut rhizosphere soil microbial communities in response to continuous cropping cycles, which could be used as bioindicator to monitor soil quality, plant health and land management practices.

scholarly journals Phylogenetic Molecular Ecological Network of Soil Microbial Communities in Response to Elevated CO2

mBio ◽  
2011 ◽  
Vol 2 (4) ◽  
Author(s):  
Jizhong Zhou ◽  
Ye Deng ◽  
Feng Luo ◽  
Zhili He ◽  
Yunfeng Yang
Keyword(s):  
Microbial Communities ◽  
Microbial Ecology ◽  
High Throughput ◽  
Network Topology ◽  
Ecosystem Functioning ◽  
Soil Microbial Communities ◽  
Microbial Populations ◽  
Metagenomic Sequencing ◽  
Sequencing Data ◽  
Soil Microbial

ABSTRACT Understanding the interactions among different species and their responses to environmental changes, such as elevated atmospheric concentrations of CO2, is a central goal in ecology but is poorly understood in microbial ecology. Here we describe a novel random matrix theory (RMT)-based conceptual framework to discern phylogenetic molecular ecological networks using metagenomic sequencing data of 16S rRNA genes from grassland soil microbial communities, which were sampled from a long-term free-air CO2 enrichment experimental facility at the Cedar Creek Ecosystem Science Reserve in Minnesota. Our experimental results demonstrated that an RMT-based network approach is very useful in delineating phylogenetic molecular ecological networks of microbial communities based on high-throughput metagenomic sequencing data. The structure of the identified networks under ambient and elevated CO2 levels was substantially different in terms of overall network topology, network composition, node overlap, module preservation, module-based higher-order organization, topological roles of individual nodes, and network hubs, suggesting that the network interactions among different phylogenetic groups/populations were markedly changed. Also, the changes in network structure were significantly correlated with soil carbon and nitrogen contents, indicating the potential importance of network interactions in ecosystem functioning. In addition, based on network topology, microbial populations potentially most important to community structure and ecosystem functioning can be discerned. The novel approach described in this study is important not only for research on biodiversity, microbial ecology, and systems microbiology but also for microbial community studies in human health, global change, and environmental management. IMPORTANCE The interactions among different microbial populations in a community play critical roles in determining ecosystem functioning, but very little is known about the network interactions in a microbial community, owing to the lack of appropriate experimental data and computational analytic tools. High-throughput metagenomic technologies can rapidly produce a massive amount of data, but one of the greatest difficulties is deciding how to extract, analyze, synthesize, and transform such a vast amount of information into biological knowledge. This study provides a novel conceptual framework to identify microbial interactions and key populations based on high-throughput metagenomic sequencing data. This study is among the first to document that the network interactions among different phylogenetic populations in soil microbial communities were substantially changed by a global change such as an elevated CO2 level. The framework developed will allow microbiologists to address research questions which could not be approached previously, and hence, it could represent a new direction in microbial ecology research.

scholarly journals Characteristics and influencing factors of soil microbial communities in different subtropical forest stands in Jinyun Mountain, Southwest China

2021 ◽  
Author(s):  
Xiaonan An ◽  
Yunqi Wang ◽  
Jialiang Zhang
Keyword(s):  
Fatty Acid ◽  
Microbial Communities ◽  
Soil Microorganisms ◽  
Phospholipid Fatty Acid ◽  
Soil Microbial Communities ◽  
Pinus Massoniana ◽  
Gram Negative Bacteria ◽  
Forest Stands ◽  
Gram Negative ◽  
Soil Microbial

Abstract BackgroundAn insight into the soil microbial functions and spatial distribution of soil resources is an important basis for evaluating and managing plant growth in subtropical forests. Soil samples were collected from five forest stands in Jinyun Mountain Natural Reserve (JMNR) in Chongqing located at the Three Gorges Reservoir area: Gordonia acuminata evergreen broad-leaved forest (GAEBF), Cunninghamia lanceolata forest (CLF), Phyllostachys pubescens forest (PPF), coniferous and broad-leaved mixed forest (CBLMF) dominated by Pinus massoniana and Gordonia acuminata (PM&GA), and the CBLMF dominated by Pinus massoniana and Symplocos setchuensis (PM&SS). Combined with phospholipid fatty acid (PLFA) analysis and Sherlock microbial identification system (MIS), the structure of soil microbial communities in different forest stands was investigated.ResultsThe results showed that the PLFAs of soil microorganisms under the forest in JMNR have a high diversity. The PLFA dominance values of the five stands were 16:0, 19:0 cyclo ω7c, 18:0, 15:0 iso and 16 :0 10-methyl. Furthermore, soil microorganisms are dominated by Gram-negative bacteria, and the PLFAs content of soil bacteria in different forest stands is higher than that of fungi PLFAs. Regarding the phospholipid fatty acid biomarkers, the two CBLMFs are the highest, followed by CLF and GAEBF and PPF is the least. Moreover, the proportion of microorganisms in the soil of different forest stands varies. Among them, MP&SS has the highest gram-negative bacteria, gram-positive bacteria, actinomycetes and fungi.ConclusionsRDA analysis shows that the main influencing factors of PLFAs in the soil of different forest stands are the content of iron oxide, aluminium oxide, organic matter and total nitrogen in the soil, which are considered to be able to reflect the soil nutrient status of JMNR effectively.

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