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Bakki M, Banane B, Marhane O, Esmaeel Q, Hatimi A, Barka EA, Azim K, Bouizgarne B. Phosphate solubilizing Pseudomonas and Bacillus combined with rock phosphates promoting tomato growth and reducing bacterial canker disease. Front Microbiol 2024; 15:1289466. [PMID: 38765677 PMCID: PMC11100333 DOI: 10.3389/fmicb.2024.1289466] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2023] [Accepted: 02/26/2024] [Indexed: 05/22/2024] Open
Abstract
Nowadays, sustainable agriculture approaches are based on the use of biofertilizers and biopesticides. Tomato (Solanum lycopersicum L.) rhizosphere could provide rhizobacteria with biofertilizing and biopesticide properties. In this study, bacteria from the rhizosphere of tomato were evaluated in vitro for plant growth promotion (PGP) properties. Five Pseudomonas isolates (PsT-04c, PsT-94s, PsT-116, PsT-124, and PsT-130) and one Bacillus isolate (BaT-68s), with the highest ability to solubilize tricalcium phosphate (TCP) were selected for further molecular identification and characterization. Isolates showed phosphate solubilization up to 195.42 μg mL-1. All isolates showed phosphate solubilization by organic acid production. The six isolates improved seed germination and showed effective root colonization when tomato seeds were coated with isolates at 106 cfu g-1 in axenic soil conditions. Furthermore, the selected isolates were tested for beneficial effects on tomato growth and nutrient status in greenhouse experiments with natural rock phosphate (RP). The results showed that inoculated tomato plants in the presence of RP have a higher shoot and root lengths and weights compared with the control. After 60 days, significant increases in plant Ca, Na, P, protein, and sugar contents were also observed in inoculated seedlings. In addition, inoculated tomato seedlings showed an increase in foliar chlorophyll a and b and total chlorophyll, while no significant changes were observed in chlorophyll fluorescence. In greenhouse, two Pseudomonas isolates, PsT-04c and PsT-130, showed ability to trigger induced systemic resistance in inoculated tomato seedlings when subsequently challenged by Clavibacter michiganensis subsp. michiganensis, the causal agent of tomato bacterial canker. High protection rate (75%) was concomitant to an increase in the resistance indicators: total soluble phenolic compounds, phenylalanine-ammonia lyase, and H2O2. The results strongly demonstrated the effectiveness of phosphate-solubilizing bacteria adapted to rhizosphere as biofertilizers for tomato crops and biopesticides by inducing systemic resistance to the causal agent of tomato bacterial canker disease.
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Affiliation(s)
- Mohamed Bakki
- Laboratory of Plant Biotechnology “Biotechnologies Végétales”, Faculty of Sciences, University Ibn Zohr (UIZ), Agadir, Morocco
| | - Badra Banane
- Laboratory of Plant Biotechnology “Biotechnologies Végétales”, Faculty of Sciences, University Ibn Zohr (UIZ), Agadir, Morocco
| | - Omaima Marhane
- Laboratory of Plant Biotechnology “Biotechnologies Végétales”, Faculty of Sciences, University Ibn Zohr (UIZ), Agadir, Morocco
| | - Qassim Esmaeel
- Unité de Recherche Résistance Induite et Bio Protection des Plantes, EA 4707 – USC INRAe1488, UFR Sciences Exactes et Naturelles, Moulin de la Housse, University of Reims Champagne-Ardenne, Reims, France
| | - Abdelhakim Hatimi
- Laboratory of Plant Biotechnology “Biotechnologies Végétales”, Faculty of Sciences, University Ibn Zohr (UIZ), Agadir, Morocco
| | - Essaid Ait Barka
- Unité de Recherche Résistance Induite et Bio Protection des Plantes, EA 4707 – USC INRAe1488, UFR Sciences Exactes et Naturelles, Moulin de la Housse, University of Reims Champagne-Ardenne, Reims, France
| | - Khalid Azim
- Integrated Crop Production Research Unit, Regional Center of Agricultural Research of Agadir, National Institute of Agricultural Research, Rabat, Morocco
| | - Brahim Bouizgarne
- Laboratory of Plant Biotechnology “Biotechnologies Végétales”, Faculty of Sciences, University Ibn Zohr (UIZ), Agadir, Morocco
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Zboralski A, Filion M. Genetic factors involved in rhizosphere colonization by phytobeneficial Pseudomonas spp. Comput Struct Biotechnol J 2020; 18:3539-3554. [PMID: 33304453 PMCID: PMC7711191 DOI: 10.1016/j.csbj.2020.11.025] [Citation(s) in RCA: 45] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2020] [Revised: 11/10/2020] [Accepted: 11/12/2020] [Indexed: 12/13/2022] Open
Abstract
Plant growth-promoting rhizobacteria (PGPR) actively colonize the soil portion under the influence of plant roots, called the rhizosphere. Many plant-beneficial Pseudomonas spp. have been characterized as PGPR. They are ubiquitous rod-shaped motile Gram-negative bacteria displaying a high metabolic versatility. Their capacity to protect plants from pathogens and improve plant growth closely depends on their rhizosphere colonization abilities. Various molecular and cellular mechanisms are involved in this complex process, such as chemotaxis, biofilm formation, secondary metabolites biosynthesis, metabolic versatility, and evasion of plant immunity. The burst in Pseudomonas spp. genome sequencing in recent years has been crucial to better understand how they colonize the rhizosphere. In this review, we discuss the recent advances regarding these mechanisms and the underlying bacterial genetic factors required for successful rhizosphere colonization.
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Affiliation(s)
- Antoine Zboralski
- Department of Biology, Université de Moncton, Moncton, NB E1A 3E9, Canada
| | - Martin Filion
- Research and Development Centre, Agriculture and Agri-Food Canada, Saint-Jean-sur-Richelieu, QC J3B 3E6, Canada
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