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Jie W.,Heilongjiang University | Jie W.,Heilongjiang East University | Jie W.,Key Laboratory of Microbiology | Liu X.,Heilongjiang University | And 3 more authors.
PLoS ONE | Year: 2013

Recent studies have shown that continuous cropping in soybean causes substantial changes to the microbial community in rhizosphere soil. In this study, we investigated the effects of continuous cropping for various time periods on the diversity of rhizosphere soil arbuscular mycorrhizal (AM) fungi in various soybean cultivars at the branching stage. The soybean cultivars Heinong 37 (an intermediate cultivar), Heinong 44 (a high-fat cultivar) and Heinong 48 (a high-protein cultivar) were seeded in a field and continuously cropped for two or three years. We analyzed the diversity of rhizosphere soil AM fungi of these soybean plants at the branching stage using morphological and denaturing gradient gel electrophoresis (DGGE) techniques. The clustering analysis of unweighted pair-group method with arithmetic averages (UPGMA) was then used to investigate the AM fungal community shifts. The results showed that increasing the number of years of continuous cropping can improve the colonization rate of AM fungi in different soybean cultivars at the branching stage. The dominant AM fungi in the experimental fields were Funneliformis mosseae and Glomus spp. The number of years of continuous cropping and the soybean cultivar both had obvious effects on the diversity of AM fungi, which was consistent with the results of colonization rate analysis. This study establishes a basis for screening dominant AM fungi of soybean. In addition, the results of this study may be useful for the development of AM fungal inoculants. © 2013 Jie et al.

Jie W.,Heilongjiang University | Jie W.,Heilongjiang East University | Jie W.,Key Laboratory of Microbiology | Bai L.,Heilongjiang East University | And 4 more authors.
Biocontrol Science and Technology | Year: 2015

This study analysed the interspecific relationships between the dominant arbuscular mycorrhizal (AM) fungus, Funneliformis mosseae, and the major soybean root rot pathogen, Fusarium oxysporum, in the rhizosphere soil of continuous cropped soybean. Our aim was to provide theoretical evidence on the AM fungi to overcome the obstacles of soybean continuous cropping. We selected soybean cultivars, including Kenfeng 16 (an intermediate cultivar), Heinong 44 (a high-fat cultivar) and Heinong 48 (a high-protein cultivar), and sowed in the soybean continuous cropping soil under different treatments. The infection status of the soybean roots during the branching period by Fu. mosseae and F. oxysporum was estimated using the standard polymerase chain reaction method, as well as their colonisation status in rhizosphere soil. The AM fungal colonisation rates and F. oxysporum disease incidence of soybean roots were determined, respectively. Quantitative polymerase chain reaction was applied to analyse the DNA content of Fu. mosseae and F. oxysporum to investigate the relationship between Fu. mosseae and F. oxysporum. The results show that both Fu. mosseae and F. oxysporum can infect the soybean roots during the branching period and colonise the rhizosphere. However, the DNA content of F. oxysporum clearly decreased in soybean root and rhizosphere samples after the inoculation with Fu. mosseae. In addition, the disease incidence of F. oxysporum significantly decreased after inoculation with Fu. mosseae, which might indicate inhibitive effects of Fu. mosseae over F. oxysporum. © 2015, Taylor & Francis.

Ge J.,Heilongjiang University | Ge J.,Key Laboratory of Microbiology | Chai Y.,Heilongjiang University | Chai Y.,Key Laboratory of Microbiology | And 4 more authors.
Shengtai Xuebao/ Acta Ecologica Sinica | Year: 2012

Soybean paste, soy sauce, preserved bean curd and lobster sauce are the four traditional fermentation foods in China. Microorganisms, especially bacterial varieties play an active role during the process of soybean paste fermentation. The bacteria are closely related to the flavor and quality of the soybean paste. In the fermentation of traditional soybean paste, monitoring different stages of the fermentation process and the dynamics of bacteria diversity, as well as controlling the bacteria succession will provide a theoretical basis for strain selection and improvement of the process for industrial production. At present, denaturing gradient gel electrophoresis (DGGE) is widely accepted as a molecular biology tool for studying complex microbial community and behavior. In this study, we used the natural fermented soybean paste as material, extracted bacteria genomic DNA, amplified the V3 region of 16SrRNA genes by PCR, and analyzed the dynamics of bacteria community structure and the dominant population during the fermentation of soybean paste using DGGE. Our results showed that the V3 region of 16SrDNA of the complex microbial community in the fermentation of traditional soybean paste were around 230 bp, containing 19 different gel bands. Sequencing of the DGGE bands revealed the 19 microorganisms, which are Aeromonas, Weissella viridescens, Staphylococcus xylosus, Lactobacillus brevis, Aeromonas media, Staphylococcus saprophyticus, Leuconostoc lactis, listeria grayi, Bacillus subtilis, Staphylococcus succinu, Bacillus firmus, Tetragenococcus halophilus and six unculturable bacteria. This result clearly reflects the diversity of the bacteria in the fermentation process. Through monitoring the abundance value and degree of dominance during the fermentation process, we found the growth of some initial populations and depression of other initial populations, in addition to the growth and evolution of some subpopulations. The application of PCR-DGGE method in the detection of bacteria diversity has led to valuable information. In addition, the succession of bacteria population displayed the following pattern in the fermentation process based on the Shannon-Weiner index, i. e. the variation of the bacteria population showed "low-high-low" pattern, while the dominant bacteria population showed a succession pattern from D8 (Uncultured Staphylococcus sp., Accession Number FJ542940. 1) to D18 (Uncultured bacterium, Accession Number EU873643. 1) and then to D6 (Staphylococcus saprophyticus, Accession Number EU855228. 1). At the initial and final stages of the fermentation process, unculturable bacteria population were dominant population, the succession speed was rapid at the initial stage of fermentation. The diversity index of the bacteria population reached peak values at 42 d and 56 d in the fermentation, which were 3.77 and 3. 65, respectively. These results have provided important knowledge towards understanding the dynamic changes of bacteria populations in the soybean paste fermentation.

Qian L.,Heilongjiang University | Qian L.,Heilongjiang East University | Qian L.,Key Laboratory of Microbiology | Yu W.J.,Heilongjiang University | And 7 more authors.
Acta Agriculturae Scandinavica Section B: Soil and Plant Science | Year: 2015

We analyzed the relationship between the dominant arbuscular mycorrhizal (AM) fungus Funneliformis mosseae and the dominant soybean root rot pathogen Fusarium oxysporum through the pot trials to help overcome obstacles to continuous cropping of soybean and to provide theoretical evidence that can be used to help prevent the reduced production induced by soybean root rot. Using qRT-PCR, we amplified the specific rDNA sequences of F. mosseae and F. oxysporum in soybean roots and rhizosphere soil and quantified the DNA contents of these fungi to determine the relationship between the dominant AM fungus F. mosseae and F. oxysporum. The DNA contents of F. oxysporum differed significantly depending on the presence of F. mosseae in both soybean roots and rhizosphere soil. Specifically, the DNA contents of F. oxysporum were reduced after inoculation with F. mosseae, suggesting that F. mosseae has a negative effect on the growth of F. oxysporum. © 2015, © 2015 Taylor & Francis.

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