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. 2022 Sep 2;11(9):1305.
doi: 10.3390/biology11091305.

Effects of Phenotypic Variation on Biological Properties of Endophytic Bacteria Bacillus mojavensis PS17

Roderic Gilles Claret Diabankana  1   2 , Shamil Zavdatovich Validov  1   3 , Alexandra Borisovna Vyshtakalyuk  4 , Amina Daminova  5 , Radik Ilyasovich Safin  2 , Daniel Mawuena Afordoanyi  1   3   6
Affiliations

Effects of Phenotypic Variation on Biological Properties of Endophytic Bacteria Bacillus mojavensis PS17

Roderic Gilles Claret Diabankana et al. Biology (Basel). .

Abstract

The use of microorganism-based products in agricultural practices is gaining more interest as an alternative to chemical methods due to their non-toxic bactericidal and fungicidal properties. Various factors influence the efficacy of the microorganisms used as biological control agents in infield conditions as compared to laboratory conditions due to ecological and physiological aspects. Abiotic factors have been shown to trigger phase variations in bacterial microorganisms as a mechanism for adapting to hostile environments. In this study, we investigated the stability of the morphotype and the effects of phenotypic variation on the biological properties of Bacillus mojavensis strain PS17. B. mojavensis PS17 generated two variants (opaque and translucent) that were given the names morphotype I and II, respectively. The partial sequence of the 16S rRNA gene revealed that both morphotypes belonged to B. mojavensis. BOX and ERIC fingerprinting PCR also showed the same DNA profiles in both morphotypes. The characteristics of morphotype I did not differ from the original strain, while morphotype II showed a lower hydrolytic enzyme activity, phytohormone production, and antagonistic ability against phytopathogenic fungi. Both morphotypes demonstrated endophytic ability in tomato plants. A low growth rate of the strain PS17(II) in a minimal medium was observed in comparison to the PS17(I) strain. Furthermore, the capacity for biocontrol of B. mojavensis PS17(II) was not effective in the suppression of root rot disease in the tomato plants caused by Fusarium oxysporum f. sp. radices-lycopersici stain ZUM2407, compared to B. mojavensis PS17(I), whose inhibition was almost 47.9 ± 1.03% effective.

Keywords: B. mojavensis; antagonistic activity; biological control; endophyte bacteria; phenotypic variation; plant colonization.

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Conflict of interest statement

The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.

Figures

Figure 1
Figure 1
The occurrence of phase variation in B. mojavensis PS17 (A). B. mojavensis PS17 morphotype I (B) and morphotype II (C) grown on 2×SG agar medium plate. Red circles show magnified colonies from specific sites on plates.
Figure 2
Figure 2
The 1.5% agarose gel electrophoresis of representative (A) BOX and (B) ERIC PCR patterns. M—DNA ladder; 1–2—B. mojavensis PS17(I); 3–4—B. mojavensis PS17(II); 5–6—the original strain of B. mojavensis PS17.
Figure 3
Figure 3
Transmission electron microscopy images of B. mojavensis PS17(I) (A,B) and B. mojavensis PS17(II) (C,D) under phenotypic variation. Red arrows—cell with electron-transparent inclusion cytoplasmic membrane (PA); Blue arrows—condensation of cell nucleoid (NC); green arrows—plasmolyzed cells (PO). Image scale: 5 µm (A,C); 2 µm (B,D).
Figure 4
Figure 4
Graph showing growth curve of B. mojavensis PS17 morphotypes I and II in M9 medium (A) and LB medium (B).
Figure 5
Figure 5
Cell lysis rate of B. mojavensis PS17 morphotypes.
Figure 6
Figure 6
Antifungal activity of the bacterial cell suspension against phytopathogenic V. dahliae (A), F. chlamydosporum (B), Fusarium spp. (C), F. solani (D), F. graminearum (E), and Forl ZUM2407 (F).
Figure 7
Figure 7
Antifungal activity of cell-free suspension (A) obtained from B. mojavensis PS17(I) and B. mojavensis PS17(II). Antifungal activity of lipopeptides extracted from (B) B. mojavensis PS17(I) and (C) B. mojavensis PS17(II) against phytopathogenic fungi Forl ZUM2407. Lipopeptide extracted with Diethyl ether (I), methanol/chloroform (II), toluene (III), and methanol (IV). Cotton wool discs amended with 50 μL of lipopeptide extracts diluted in (0.5%) DMSO were used for antifungal ability.
Figure 8
Figure 8
Effect of phenotypic variation on hydrolytic enzyme activity ((A) protease, (B) glucanase, (C) cellulase), and (D) Indole-3-acetic acid production (I-without tryptophan; II-with tryptophan) of B. mojavensis PS17. The experiment was performed in triplicates and repeated twice. Statistical differences at p-value < 0.05 between groups are indicated by different letters.
Figure 9
Figure 9
The endophytic ability of B. mojavensis P17 morphotypes I and II to colonize tomato plants. B. mojavensis P17(II) isolated from root (A) and shoot (B) surface-sterilized growth on LB medium. B. mojavensis PS17(I) isolated from root (C) and shoot (D) surface-sterilized growth on LB medium.
Figure 10
Figure 10
Plant growth-promoting activity of B. mojavensis PS17 morphotypes on (A) shoots, (B) roots, and (C) fresh weight of tomato plants. (D) Photo recording tomato plant growth 3 weeks after seed sowing. The experiment was performed in triplicate and repeated twice. Statistical differences at p-value < 0.05 between groups are indicated by different letters.
Figure 11
Figure 11
Biocontrol properties (A) and germination rates (B) of B. mojavensis PS17 morphotypes I and II on tomato plants against ForI ZUM2407, PS17(I), PS(II), and PCL1670. The experiment was performed in duplicate and repeated twice. Statistical differences between groups are indicated by different letters (a and b) to the least significant difference at a p-value < 0.05.
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References

    1. Hussain T., Singh S., Danish M., Pervez R., Hussain K., Husain R. Natural metabolites: An eco-friendly approach to manage plant diseases and for better agriculture farming. In: Singh J., Yadav A., editors. Natural Bioactive Products in Sustainable Agriculture. Springer; Singapore: 2020. pp. 1–13. - DOI
    1. Saunders N.J., Moxon E.R., Gravenor M.B. Mutation rates: Estimating phase variation rates when fitness differences are present and their impact on population structure. Microbiol. Soc. 2003;149:485–495. doi: 10.1099/mic.0.25807-0. - DOI - PubMed
    1. Wisniewski-Dyé F., Vial L. Phase and antigenic variation mediated by genome modifications. Antonie Leeuwenhoek. 2008;94:493–515. doi: 10.1007/s10482-008-9267-6. - DOI - PubMed
    1. Bayliss C.D. Determinants of phase variation rate and the fitness implications of differing rates for bacterial pathogens and commensals. FEMS Microbiol. Rev. 2009;33:504–520. doi: 10.1111/j.1574-6976.2009.00162.x. - DOI - PubMed
    1. Bayliss C.D., Bidmos F.A., Anjum A., Manchev V.T., Richards R.L., Grossier J.P., Tretyakov M.V. Phase variable genes of Campylobacter jejuni exhibit high mutation rates and specific mutational patterns but mutability is not the major determinant of population structure during host colonisation. Nucleic Acids Res. 2012;40:5876–5889. doi: 10.1093/nar/gks246. - DOI - PMC - PubMed

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