Biotechnology Bulletin ›› 2025, Vol. 41 ›› Issue (7): 299-311.doi: 10.13560/j.cnki.biotech.bull.1985.2025-0070

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Isolation and Identification of Endophytic Bacteria from Saposhnikovia divaricata and Analysis of Its Growth-promoting Characteristics

SUN Meng-xue1(), ZHANG Yi-ying1, Xu Peng2, SUN Zhuo1, WANG Yun-he1(), HAN Zhong-ming1,3()   

  1. 1.Jilin Agricultural University, College of Chinese Medicinal Materias, Key Laboratory of Ecosystem and Ecological Restoration of Jilin Province, Changchun 130118
    2.Chengde Chinese Herbal Medicine Green Planting Technical Service Centre, Chengde 067000
    3.Jilin Jilong Northeast Seabuckthorn Industry Co. , Ltd. , Da’an 131300
  • Received:2025-01-21 Online:2025-07-26 Published:2025-07-22
  • Contact: WANG Yun-he, HAN Zhong-ming E-mail:17860368861@163.com;wangyunhe2015@163.com;hanzm2008@126.com

Abstract:

Objective The growth-promoting strains were isolated and screened from the healthy roots of Saposhnikovia divaricata, and their growth-promoting effects on S. divaricata were investigated. The potential of endophytic bacteria for development and utilization was mined. Method Endophytic bacteria were isolated from healthy S. divaricata roots by dilution coating method and growth-promoting bacteria with nitrogen fixation, phosphorus solubilization, IAA production and siderophore production were screened by selective medium. The growth-promoting strains were classified by morphological, physiological and biochemical identification and 16S rRNA analysis. The colonization ability of endophytic bacteria in soil and its effect on the growth of S. divaricata were investigated based on antibiotic labeling method and pot experiment. Result A total of 202 endophytic bacteria were isolated from the roots of S. divaricata, 26 strains had the ability of nitrogen fixation, 21 strains had the ability to dissolve phosphorus, 24 strains had the ability to produce IAA, and 27 strains had the ability to produce siderophores. Two strains of endophytic bacteria MX-56 and MX-31 had three or more different growth-promoting functions, were identified as Klebsiella michiganensis and Pseudomonas koreensis. Two rifampicin-resistant strains stably colonized in the rhizosphere soil of S. divaricata. In the pot experiment, compared with CK, MX-56 had the most significant effect on plant height, root length, root diameter, aboveground fresh weight, root fresh weight and root dry weight of S. divaricata, increased 13.47%, 43.04%, 42.75%, 31.43%, 63.21% and 77.12% (P<0.05). Compared to CK, the total contents of two chromones in S. divaricata plants treated with strain MX-31 and MX-56 respectively increased by 33.72% and 30.23%. Conclusion In this study, two strains of P. koreaensis MX-31 and K. michiganensis MX-56 with good growth-promoting effect are isolated and screened from healthy S. divaricata, it may significantly increase the biomass and the content of effective components of S. divaricata.

Key words: Saposhnikovia divaricata, endophytic bacteria, Klebsiella michiganensis, Pseudomonas koreensis, growth promotion