Biotechnology Bulletin ›› 2022, Vol. 38 ›› Issue (12): 223-232.doi: 10.13560/j.cnki.biotech.bull.1985.2022-0078

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Isolation and Screening of Endophytes Producing Indole Acetic Acid from Polygonatum cyrtonema Hua. and Its Effect on Seed Germination of Polygonatum

DU Jia-hui1(), XU Wei-fang1(), YANG Xiao-dong1, TAN Song1, YIN Deng-ke1,2,3, LIU Yuan-xu1,2()   

  1. 1. School of Pharmacy,Anhui University of Chinese Medicine,Hefei 230012
    2. Institute of Pharmaceutics in Anhui Academy of Chinese Medicine,Hefei 230012
    3. Anhui Province Key Laboratory of Research & Development of Chinese Medicine,Hefei 230012
  • Received:2022-01-19 Online:2022-12-26 Published:2022-12-29
  • Contact: XU Wei-fang,LIU Yuan-xu E-mail:1650268474@qq.com;xuweifang@ahtcm.edu.cn;yuanxliu@ahtcm.edu.cn

Abstract:

The endophytic bacteria that can promote the seed germination of Polygonatum were isolated and screened from the healthy roots of Polygonatum cyrtonema Hua.,in order to lay a theoretical foundation for solving the shortage of Polygonatum resources. The endophytes were isolated and purified by the traditional tissue culture method,and the IAA-producing bacteria were screened by the Salkowski reaction(Salkowski method). The taxonomic status of the target strains was determined by morphological observation,physiological and biochemical characterization,and 16S rDNA sequence analysis. The germination-promoting effect of the target strains on the seeds of Polygonatum was verified by greenhouse paper-bed experiments. The results showed that 34 endophytes were isolated and purified from Polygonatum cyrtonema Hua.,including 25 endophytic bacteria and 9 endophytic fungi. Two endophytic bacteria HNC2 and HPB1 with stable and high content of IAA were screened out,and their IAA production capacity was as high as 4.833 mg/L and 4.608 mg/L,respectively. The results of bacterial identification showed that strains HNC2 and HPB1 were Bacillus sp. and Staphylococcus sp.,respectively. The experimental results regarding the effect of the strains on seed germination showed that both of the growth-promoting bacteria Bacillus sp. HNC2 and Staphylococcus sp. HPB1 significantly increased the germination potential and germination rate of Polygonatum seeds compared to the sterile water and medium controls,and had different degrees of growth-promoting effects on the growth of seedlings. Polygonatum cyrtonema Hua. harbors abundant endophytic bacteria,of which Bacillus sp. HNC2 and Staphylococcus sp. HPB1 are expected to be further developed as microbial fertilizer to increase the germination rate of Polygonatum seeds.

Key words: Polygonatum cyrtonema Hua., endophytes, screening, indole acetic acid, plant-growth-promoting effect