Biofilm Producing Rhizobacteria With Multiple Plant Growth-Promoting Traits Promote Growth of Tomato Under Water-Deficit Stress
Plant growth-promoting rhizobacteria (PGPR) not only enhance plant growth but also control phytopathogens and mitigate abiotic stresses, including water-deficit stress. In this study, 21 (26.9%) rhizobacterial strains isolated from drought-prone ecosystems of Bangladesh were able to form air–liquid...
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| Vydané v: | Frontiers in microbiology Ročník 11; s. 542053 |
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| Hlavní autori: | , , , , , , , , , , |
| Médium: | Journal Article |
| Jazyk: | English |
| Vydavateľské údaje: |
Switzerland
Frontiers Media S.A
26.11.2020
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| Predmet: | |
| ISSN: | 1664-302X, 1664-302X |
| On-line prístup: | Získať plný text |
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| Shrnutí: | Plant growth-promoting rhizobacteria (PGPR) not only enhance plant growth but also control phytopathogens and mitigate abiotic stresses, including water-deficit stress. In this study, 21 (26.9%) rhizobacterial strains isolated from drought-prone ecosystems of Bangladesh were able to form air–liquid (AL) biofilms in the glass test tubes containing salt-optimized broth plus glycerol (SOBG) medium. Based on 16S rRNA gene sequencing,
Pseudomonas chlororaphis
(ESR3 and ESR15),
P. azotoformans
ESR4,
P. poae
ESR6,
P. fluorescens
(ESR7 and ESR25),
P. gessardii
ESR9,
P. cedrina
(ESR12, ESR16, and ESR23),
P. veronii
(ESR13 and ESR21),
P. parafulva
ESB18,
Stenotrophomonas maltophilia
ESR20,
Bacillus cereus
(ESD3, ESD21, and ESB22),
B. horikoshii
ESD16,
B. aryabhattai
ESB6,
B. megaterium
ESB9, and
Staphylococcus saprophyticus
ESD8 were identified. Fourier transform infrared spectroscopy studies showed that the biofilm matrices contain proteins, polysaccharides, nucleic acids, and lipids. Congo red binding results indicated that these bacteria produced curli fimbriae and nanocellulose-rich polysaccharides. Expression of nanocellulose was also confirmed by Calcofluor binding assays and scanning electron microscopy.
In vitro
studies revealed that all these rhizobacterial strains expressed multiple plant growth-promoting traits including N
2
fixation, production of indole-3-acetic acid, solubilization of nutrients (P, K, and Zn), and production of ammonia, siderophores, ACC deaminase, catalases, lipases, cellulases, and proteases. Several bacteria were also tolerant to multifarious stresses such as drought, high temperature, extreme pH, and salinity. Among these rhizobacteria,
P. cedrina
ESR12,
P. chlororaphis
ESR15, and
B. cereus
ESD3 impeded the growth of
Xanthomonas campestris
pv.
campestris
ATCC 33913, while
P. chlororaphis
ESR15 and
B. cereus
ESD21 prevented the progression of
Ralstonia solanacearum
ATCC
®
11696
TM
. In a pot experiment, tomato plants inoculated with
P. azotoformans
ESR4,
P. poae
ESR6,
P. gessardii
ESR9,
P. cedrina
ESR12,
P. chlororaphis
ESR15,
S. maltophilia
ESR20,
P. veronii
ESR21, and
B. aryabhattai
ESB6 exhibited an increased plant growth compared to the non-inoculated plants under water deficit-stressed conditions. Accordingly, the bacterial-treated plants showed a higher antioxidant defense system and a fewer tissue damages than non-inoculated plants under water-limiting conditions. Therefore, biofilm-producing PGPR can be utilized as plant growth promoters, suppressors of plant pathogens, and alleviators of water-deficit stress. |
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| Bibliografia: | ObjectType-Article-1 SourceType-Scholarly Journals-1 ObjectType-Feature-2 content type line 23 These authors have contributed equally to this work This article was submitted to Microbial Symbioses, a section of the journal Frontiers in Microbiology Edited by: Alok Kumar Srivastava, National Bureau of Agriculturally Important Microorganisms (ICAR), India Reviewed by: Valeria Ventorino, University of Naples Federico II, Italy; Puneet Singh Chauhan, National Botanical Research Institute (CSIR), India |
| ISSN: | 1664-302X 1664-302X |
| DOI: | 10.3389/fmicb.2020.542053 |