Microbial Ecology

, Volume 77, Issue 3, pp 651–663 | Cite as

Genomic and Functional Characterization of the Endophytic Bacillus subtilis 7PJ-16 Strain, a Potential Biocontrol Agent of Mulberry Fruit Sclerotiniose

  • Wei-fang Xu
  • Hui-shuang Ren
  • Ting Ou
  • Ting Lei
  • Jun-hong Wei
  • Chuan-shu Huang
  • Tian Li
  • Gary Strobel
  • Ze-yang ZhouEmail author
  • Jie XieEmail author
Plant Microbe Interactions


Bacillus sp. 7PJ-16, an endophytic bacterium isolated from a healthy mulberry stem and previously identified as Bacillus tequilensis 7PJ-16, exhibits strong antifungal activity and has the capacity to promote plant growth. This strain was studied for its effectiveness as a biocontrol agent to reduce mulberry fruit sclerotiniose in the field and as a growth-promoting agent for mulberry in the greenhouse. In field studies, the cell suspension and supernatant of strain 7PJ-16 exhibited biocontrol efficacy and the lowest disease incidence was reduced down to only 0.80%. In greenhouse experiments, the cell suspension (1.0 × 106 and 1.0 × 105 CFU/mL) and the cell-free supernatant (100-fold and 1000-fold dilution) stimulated mulberry seed germination and promoted mulberry seedling growth. In addition, to accurately identify the 7PJ-16 strain and further explore the mechanisms of its antifungal and growth-promoting properties, the complete genome of this strain was sequenced and annotated. The 7PJ-16 genome is comprised of two circular plasmids and a 4,209,045-bp circular chromosome, containing 4492 protein-coding genes and 116 RNA genes. This strain was ultimately designed as Bacillus subtilis based on core genome sequence analyses using a phylogenomic approach. In this genome, we identified a series of gene clusters that function in the synthesis of non-ribosomal peptides (surfactin, fengycin, bacillibactin, and bacilysin) as well as the ribosome-dependent synthesis of tasA and bacteriocins (subtilin, subtilosin A), which are responsible for the biosynthesis of numerous antimicrobial metabolites. Additionally, several genes with function that promote plant growth, such as indole-3-acetic acid biosynthesis, the production of volatile substances, and siderophores synthesis, were also identified. The information described in this study has established a good foundation for understanding the beneficial interactions between endophytes and host plants, and facilitates the further application of B. subtilis 7PJ-16 as an agricultural biofertilizer and biocontrol agent.


Bacillus subtilis Control efficiency Plant growth promotion Genome sequence Antimicrobial metabolites 



The authors acknowledge the financial support of the National Natural Science Foundation of China (31601678) to Jie Xie, the Fundamental Research Funds for the Central Universities (XDJK2018D020) to Ting Ou, and the Natural Science Foundation of Chongqing (cstc2015jcyjys80001) to Jie Xie.

Supplementary material

248_2018_1247_MOESM1_ESM.docx (4.6 mb)
ESM 1 (DOCX 4714 kb)


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Copyright information

© Springer Science+Business Media, LLC, part of Springer Nature 2018

Authors and Affiliations

  • Wei-fang Xu
    • 1
    • 2
  • Hui-shuang Ren
    • 1
    • 2
  • Ting Ou
    • 1
    • 2
  • Ting Lei
    • 3
  • Jun-hong Wei
    • 1
    • 2
  • Chuan-shu Huang
    • 3
  • Tian Li
    • 1
    • 2
  • Gary Strobel
    • 4
  • Ze-yang Zhou
    • 1
    • 2
    • 5
    Email author
  • Jie Xie
    • 1
    • 2
    Email author
  1. 1.State Key Laboratory of Silkworm Genome Biology, College of BiotechnologySouthwest UniversityChongqingPeople’s Republic of China
  2. 2.Key Laboratory of Sericultural Biology and Genetic Breeding, Ministry of Agriculture, College of BiotechnologySouthwest UniversityChongqingPeople’s Republic of China
  3. 3.Institute of Sericulture Science and Technology ResearchChongqingPeople’s Republic of China
  4. 4.Department of Plant SciencesMontana State UniversityBozemanUSA
  5. 5.College of Life ScienceChongqing Normal UniversityChongqingPeople’s Republic of China

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