Li Li

Shandong Agricultural University, China

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Publications (6)8.77 Total impact

  • Biodiversity Science 01/2015; 23(1):68-78. DOI:10.17520/biods.2014148
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    ABSTRACT: Competitiveness for nodulation is one of the major restrictive factors in symbiotic nitrogen fixation between rhizobia and their host legumes. Soybean root exudates that include a variety of compounds are thought to act as signals to trigger the early symbiotic events between Bradyrhizobium diazoefficiens and soybeans, and thus they act as a key determinant of the competitiveness for nodulation. To gain a better understanding of the molecular mechanism of competitiveness at the level of protein expression, we compared the proteomic responses of two B. diazoefficiens strains that demonstrated completely different nodulation abilities, strain 4534 being the most competitive and strain 4222 being the least competitive in nodulation. In the proteomic analysis, 40 of the 65 and 22 of the 29 differential proteins were identified in response to soybean root exudates in strain 4534 and strain 4222, respectively. Compared to strain 4222, a higher amount and a number of differential proteins were detected in strain 4534, including S-adenosylmethionine synthetase (SAMS), PhyR-sigma(EcfG) regulon, ABC-type transporters, flagellar proteins, molecular chaperones, and proteins involved in redox state maintenance as well as several unknown proteins. Noteworthy was the induction of the PhyR-sigma(EcfG) regulon and flagellar proteins, recently demonstrated to be involved in the competitiveness for nodulation in Bradyrhizobium japonicum. Our results indicate that the role of root exudates can go far beyond inducing the expression of nodulation genes in B. diazoefficiens. Many other proteins/enzymes involved in the metabolism and environmental fitness were also upregulated when exposed to root exudates. More proteins were upregulated by the high nodulation competitive strain than that by the low, and the reasons for this need further investigation. The outcome of such study may contribute to our understanding of molecular mechanisms of different competitiveness in B. diazoefficiens as well as specific adaptation in the legume host.
    Biology and Fertility of Soils 02/2014; 51(2):251-260. DOI:10.1007/s00374-014-0969-9 · 3.40 Impact Factor
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    ABSTRACT: Paenibacillus mucilaginosus is a ubiquitous functional bacterium in microbial fertilizer. Here we report the complete sequence of P. mucilaginosus 3016. Multiple sets of functional genes have been found in the genome. To the best of our knowledge, this is the first announcement about the complete genome sequence of a P. mucilaginosus strain.
    Journal of bacteriology 05/2012; 194(10):2777-8. DOI:10.1128/JB.00323-12 · 2.69 Impact Factor
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    ABSTRACT: Paenibacillus mucilaginosus is widely used as microbial fertilizers, therefore, rapid identification of this species by Polymerase Chain Reaction (PCR) is necessary for detection and ecological evaluation of microbial fertilizer. A species-specific primer pair of P. mucilaginosus, orf06701-F(5'-ATGGAGGAAACATGGGGTGA-3')/orf06701-R (5'-TCAGGAATGAAGGCCCCCTT-3') was designed. Optimization of PCR, specificity and sensitivity determination were followed and the rapid identification was established. A single band with 333 bp was consistently amplified from all the strains of P. mucilaginosus tested and negative results were obtained from all the reference strains, such as other strains of Paenibacillus and Bacillus. The PCR detection limitation was 400 - 1000 cells per assay, indicating the sensitivity of the rapid culture-PCR method. To verify the rapid identification, soil was sampled and cultured. Five of 11 soil isolates were rapidly identified as P. mucilaginosus by the method, and the similarity of 333bp sequences were 100%. The methods can be used in the rapid identification of P. mucilaginosus and the results will provide technical supports for the detection and ecological evaluation of microbial fertilizer.
    ACTA MICROBIOLOGICA SINICA 11/2011; 51(11):1485-93.
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    ABSTRACT: Paenibacillus polymyxa SC2 is an important plant growth-promoting rhizobacterium (PGPR). Here, we report the complete genome sequence of P. polymyxa SC2. Multiple sets of functional genes have been found in the genome. As far as we know, this is the first complete genome sequence of Paenibacillus polymyxa.
    Journal of bacteriology 10/2010; 193(1):311-2. DOI:10.1128/JB.01234-10 · 2.69 Impact Factor
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    ABSTRACT: To discriminate the strains of Bacillus subtilis group including B. subtilis, B. amyloliquefaciens, B. licheniformis, and B. pumilus, a rapid and accurate distinguishing method is essential for the identification of the target strains to ensure the quality and safety of microbial fertilizers. By analyzing unique nucleotide sequences of the rpoA, gyrA and 16S rDNA genes, 4 pairs of species-specific primers were optimized and the multiplex PCR was developed to discriminate and identify B. subtilis, B. amyloliquefaciens, B. licheniformis and B. pumilus. Thirty-three reference strains belonging to three genera of Bacillus, Paenibacillus and Brevibacillus were tested and the anticipated results appeared except for four species with cross amplification results with the primers of B. pumilus. However, the four species can be easily discriminated by morphology characters. In addition, the multiplex-PCR results of 23 strains of B. subtilis group isolated from MF products were identical with the biochemical assay. The newly constructed multiplex-PCR assay is species-specific and effective. This method can be used to detect and identify the strains of B. subtilis group from microbial fertilizers products.
    ACTA MICROBIOLOGICA SINICA 05/2008; 48(5):651-6.