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. 2023 Apr 18:14:1180319.
doi: 10.3389/fmicb.2023.1180319. eCollection 2023.

Isolation and identification of mycorrhizal helper bacteria of Vaccinium uliginosum and their interaction with mycorrhizal fungi

Zhiyu Yang  1   2 , Hui Dong  1   2 , Sai Zhang  1   2 , Jing Jiang  1   2 , Haifeng Zhu  1   2 , Hongyi Yang  1   2 , Lili Li  3
Affiliations

Isolation and identification of mycorrhizal helper bacteria of Vaccinium uliginosum and their interaction with mycorrhizal fungi

Zhiyu Yang et al. Front Microbiol. .

Abstract

Mycorrhizal helper bacteria (MHB) can promote mycorrhizal fungal colonization and form mycorrhizal symbiosis structures. To investigate the effect of interactions between mycorrhizal beneficial microorganisms on the growth of blueberry, 45 strains of bacteria isolated from the rhizosphere soil of Vaccinium uliginosum were screened for potential MHB strains using the dry-plate confrontation assay and the bacterial extracellular metabolite promotion method. The results showed that the growth rate of mycelium of Oidiodendron maius 143, an ericoid mycorrhizal fungal strain, was increased by 33.33 and 77.77% for bacterial strains L6 and LM3, respectively, compared with the control in the dry-plate confrontation assay. In addition, the extracellular metabolites of L6 and LM3 significantly promoted the growth of O. maius 143 mycelium with an average growth rate of 40.9 and 57.1%, respectively, the cell wall-degrading enzyme activities and genes of O. maius 143 was significantly increased. Therefore, L6 and LM3 were preliminarily identified as potential MHB strains. In addition, the co-inoculated treatments significantly increased blueberry growth; increased the nitrate reductase, glutamate dehydrogenase, glutamine synthetase, and glutamate synthase activities in the leaves; and promoted nutrient uptake in blueberry. Based on the physiological, and 16S rDNA gene molecular analyses, we initially identified strain L6 as Paenarthrobacter nicotinovorans and LM3 as Bacillus circulans. Metabolomic analysis revealed that mycelial exudates contain large amounts of sugars, organic acids and amino acids, which can be used as substrates to stimulate the growth of MHB. In conclusion, L6 and LM3 and O. maius 143 promote each other's growth, while co-inoculation of L6 and LM3 with O. maius 143 can promote the growth of blueberry seedlings, providing a theoretical basis for further studies on the mechanism of ericoid mycorrhizal fungi-MHB-blueberry interactions. It laid the technical foundation for the exploitation of biocontrol strain resources and the development of biological fertilizer.

Keywords: blueberry; ericoid mycorrhizal fungi; interactions; mycorrhiza; mycorrhizal helper bacteria.

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Conflict of interest statement

The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.

Figures

Figure 1
Figure 1
Effects of the fermented product of L6 or LM3 on Oidiodendron maius 143 growth. Mycelial dry weight of 143 in YPD liquid media supplemented with the fermentation broth of L6 or the fermentation broth of LM3. 143 is O. maius 143; 143 + L6 is the co-inoculation of the O. maius 143 and L6 isolates; and 143 + LM3 is the co-inoculation of the O. maius 143 and LM3 isolates. The treatments labeled with different letters are significantly different according to Tukey’s HSD at p < 0.05. Bars represent the standard deviations of the means.
Figure 2
Figure 2
Effects of the fermented product of L6 or LM3 on the enzyme activities and gene expression of O. maius 143. (A) Effects of the fermented product of L6 or LM3 on the enzyme activities of O. maius 143. (B) Effects of L6 or LM3 on the expression of the mycorrhizal formation–related genes of O. maius 143. Treatments labeled with different letters are significantly different according to Tukey’s HSD at p < 0.05. Bars represent the standard deviations of the means.
Figure 3
Figure 3
Microscopic observation of blueberry roots inoculated with O. maius 143. (A) Blueberry alone, roots of control seedlings (without inoculation) with no mycorrhizal colonization. (B) Blueberry with the mycorrhizal fungus O. maius 143. (C) Blueberry with the mycorrhizal fungus O. maius 143 and L6 isolates. (D) Blueberry with the mycorrhizal fungus O. maius 143 and LM3 isolate. Hyphal growth inside the epidermal cells of roots from inoculated plants is shown in B, C, and D. The red arrows are mycelial coils.
Figure 4
Figure 4
Effects of potential MHB strains and O. maius 143 on the enzyme activities of blueberry leaves. (A) Effect of potential MHB strains and O. maius 143 on the GOGAT activity of blueberry. (B) Effect of potential MHB strains and O. maius 143 on the GDH dismutase activity of blueberry. (C) Effect of potential MHB strains and O. maius 143 on the GS activity of blueberry. (D) Effect of potential MHB strains and O. maius 143 on the NR activity of blueberry. CK is the control without any inoculums. The treatments labeled with different letters are significantly different according to Tukey’s HSD at p < 0.05. Bars represent the standard deviations of the means.
Figure 5
Figure 5
Neighbor-joining phylogenetic tree based on the 16S rDNA sequence data of potential MHB strains L6 and LM3 isolated from Vaccinium uliginosum rhizosphere soil. Numerical values above the branches indicate the bootstrap percentiles from 1,000 replicates. Bootstrap numbers higher than 50% are indicated. Horizontal branch lengths are proportional to the scale of the substitutions.
Figure 6
Figure 6
A proposed model illustrating the mechanism through which mycorrhizal helper bacterium P. nicotinovorans L6 or B. circulans LM3 improve the growth of blueberry.
See this image and copyright information in PMC

References

    1. Abbà S., Vallino M., Daghino S., Di V. L., Borriello R., Perotto S. A. (2011). PLAC8-containing protein from an endomycorrhizal fungus confers cadmium resistance to yeast cells by interacting with Mlh3p. Nucleic Acids Res. 39, 7548–7563. doi: 10.1093/nar/gkr336 - DOI - PMC - PubMed
    1. Adeleke R., Dames J. F. (2014). Kalaharituber pfeilii and associated bacterial interactions. S. Afr. J. Bot. 90, 68–73. doi: 10.1016/j.sajb.2013.10.003 - DOI
    1. Ansari F. A., Ahmad I. (2019). Fluorescent pseudomonas-FAP2 and bacillus licheniformis interact positively in biofilm mode enhancing plant growth and photosynthetic attributes. Sci. Rep. 9:4547. doi: 10.1038/s41598-019-40864-4, PMID: - DOI - PMC - PubMed
    1. Aspray T. J., Jones E. E., Davies M. W., Shipman M., Bending G. D. (2013). Increased hyphal branching and growth of ectomycorrhizal fungus Lactarius rufus by the helper bacterium Paenibacillus sp. Mycorrhiza 23, 403–410. doi: 10.1007/s00572-013-0483-1, PMID: - DOI - PubMed
    1. Bharadwaj D. P., Alström S., Lundquist P. O. (2012). Interactions among Glomus irregulare, arbuscular mycorrhizal spore-associated bacteria, and plant pathogens under in vitro conditions. Mycorrhiza 22, 437–447. doi: 10.1007/s00572-011-0418-7, PMID: - DOI - PubMed

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