Biotechnology Bulletin ›› 2023, Vol. 39 ›› Issue (10): 246-255.doi: 10.13560/j.cnki.biotech.bull.1985.2023-0590

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Identification, Biocontrol and Plant Growth-promoting Potential of Endophytic Bacterial Strain JY-3-1R from Aconitum carmichaelii Debx.

ZOU Lan1(), WANG Qian1, LI Mu-yi1, YE Kun-hao2, HUANG Jing1()   

  1. 1. School of Life Science and Engineering, Southwest University of Science and Technology, Mianyang 621010
    2. Institute of Traditional Medicinal Materials, Mianyang Academy of Agricultural Science, Mianyang 621023
  • Received:2023-06-21 Online:2023-10-26 Published:2023-11-28
  • Contact: HUANG Jing E-mail:zoulan@swust.edu.cn;huang.jing@swust.edu.cn

Abstract:

In order to provide promising microbial resource for the control of soil-borne diseases in Aconitum carmichaelii Debx., endophytic bacterial strains with biocontrol and plant growth promoting potential were isolated and screened from healthy A. carmichaelii plants. Pure culture method was used to isolate endophytic bacteria, and dual-culture method was to check the antagonistic activity of candidate strains against pathogens. Multi-locus housekeeping gene sequence analysis was to investigate phylogeny of the strain. Enzyme- and siderophore-producing capacities of bacterial strain were measured on plates. Salkowski method was applied to measure indoleacetic acid(IAA)-producing ability of the strain. Field experiment was employed to demonstrate plant growth promoting ability and biocontrol potential against southern blight in A. carmichaelii. One strain JY-3-1R screened from 111 A. carmichaelii endophytic bacteria showed significant antagonistic activity against Sclerotium rolfsii and Fusarium oxysporum in vitro. The JY-3-1R was identified as Bacillus amyloliquefaciens. Cell-free culture filtrate of JY-3-1R presented 100% inhibition on the hyphal growth and sclerotia germination of S. rolfsii. JY-3-1R was able to produce IAA, siderophore, protease, cellulase, glucanase, also had the functional genes of synthesizing iturin, fengyin, surfactin, bacillomycin, bacilysin, bacillaene, and macrolactin. Under field conditions, JY-3-1R inoculation reduced around 40% of southern blight occurrence, whose biocontrol rates ranged from 61.53% to 84.61%. This biocontrol efficiency lasted at least for 30 d. Meanwhile, JY-3-1R inoculation promoted 34.34%, 82.59% and 56.08% of stem, main root and lateral root dry weight, respectively of A. carmichaelii. Altogether, JY-3-1R demonstrated both plant growth promoting and biocontrol potential, and could be used as good candidate of biofertilizer and biocontrol agent of A. carmichaelii.

Key words: endophytic bacteria, biocontrol, plant growth promotion, southern blight