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Ait Bessai S, Cruz J, Carril P, Melo J, Santana MM, Mouazen AM, Cruz C, Yadav AN, Dias T, Nabti EH. The Plant Growth-Promoting Potential of Halotolerant Bacteria Is Not Phylogenetically Determined: Evidence from Two Bacillus megaterium Strains Isolated from Saline Soils Used to Grow Wheat. Microorganisms 2023; 11:1687. [PMID: 37512860 PMCID: PMC10384442 DOI: 10.3390/microorganisms11071687] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2023] [Revised: 06/21/2023] [Accepted: 06/26/2023] [Indexed: 07/30/2023] Open
Abstract
(1) Background: Increasing salinity, further potentiated by climate change and soil degradation, will jeopardize food security even more. Therefore, there is an urgent need for sustainable agricultural practices capable of maintaining high crop yields despite adverse conditions. Here, we tested if wheat, a salt-sensitive crop, could be a good reservoir for halotolerant bacteria with plant growth-promoting (PGP) capabilities. (2) Methods: We used two agricultural soils from Algeria, which differ in salinity but are both used to grow wheat. Soil halotolerant bacterial strains were isolated and screened for 12 PGP traits related to phytohormone production, improved nitrogen and phosphorus availability, nutrient cycling, and plant defence. The four 'most promising' halotolerant PGPB strains were tested hydroponically on wheat by measuring their effect on germination, survival, and biomass along a salinity gradient. (3) Results: Two halotolerant bacterial strains with PGP traits were isolated from the non-saline soil and were identified as Bacillus subtilis and Pseudomonas fluorescens, and another two halotolerant bacterial strains with PGP traits were isolated from the saline soil and identified as B. megaterium. When grown under 250 mM of NaCl, only the inoculated wheat seedlings survived. The halotolerant bacterial strain that displayed all 12 PGP traits and promoted seed germination and plant growth the most was one of the B. megaterium strains isolated from the saline soil. Although they both belonged to the B. megaterium clade and displayed a remarkable halotolerance, the two bacterial strains isolated from the saline soil differed in two PGP traits and had different effects on plant performance, which clearly shows that PGP potential is not phylogenetically determined. (4) Conclusions: Our data highlight that salt-sensitive plants and non-saline soils can be reservoirs for halotolerant microbes with the potential to become effective and sustainable strategies to improve plant tolerance to salinity. However, these strains need to be tested under field conditions and with more crops before being considered biofertilizer candidates.
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Affiliation(s)
- Sylia Ait Bessai
- Laboratoire de Maitrise des Energies Renouvelables, Faculté des Sciences de la Nature et de la Vie, Université de Bejaia, Bejaia 06000, Algeria
| | - Joana Cruz
- cE3c-Centre for Ecology, Evolution and Environmental Changes and CHANGE-Global Change and Sustainability Institute, Faculdade de Ciências, Universidade de Lisboa, Campo Grande, 1749-016 Lisboa, Portugal
- Competence Centre for Molecular Biology, SGS Molecular, Polo Tecnológico de Lisboa, Rua Cesina Adães Bermudes, Lt 11, 1600-604 Lisboa, Portugal
| | - Pablo Carril
- cE3c-Centre for Ecology, Evolution and Environmental Changes and CHANGE-Global Change and Sustainability Institute, Faculdade de Ciências, Universidade de Lisboa, Campo Grande, 1749-016 Lisboa, Portugal
| | - Juliana Melo
- cE3c-Centre for Ecology, Evolution and Environmental Changes and CHANGE-Global Change and Sustainability Institute, Faculdade de Ciências, Universidade de Lisboa, Campo Grande, 1749-016 Lisboa, Portugal
| | - Margarida M Santana
- cE3c-Centre for Ecology, Evolution and Environmental Changes and CHANGE-Global Change and Sustainability Institute, Faculdade de Ciências, Universidade de Lisboa, Campo Grande, 1749-016 Lisboa, Portugal
| | - Abdul M Mouazen
- Department of Environment, Faculty of Bioscience Engineering, Ghent University, 9000 Gent, Belgium
| | - Cristina Cruz
- cE3c-Centre for Ecology, Evolution and Environmental Changes and CHANGE-Global Change and Sustainability Institute, Faculdade de Ciências, Universidade de Lisboa, Campo Grande, 1749-016 Lisboa, Portugal
| | - Ajar Nath Yadav
- Department of Biotechnology, Dr. Khem Singh Gill Akal College of Agriculture, Eternal University, Baru Sahib, Sirmour 173101, India
| | - Teresa Dias
- cE3c-Centre for Ecology, Evolution and Environmental Changes and CHANGE-Global Change and Sustainability Institute, Faculdade de Ciências, Universidade de Lisboa, Campo Grande, 1749-016 Lisboa, Portugal
| | - El-Hafid Nabti
- Laboratoire de Maitrise des Energies Renouvelables, Faculté des Sciences de la Nature et de la Vie, Université de Bejaia, Bejaia 06000, Algeria
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Ganugi P, Fiorini A, Rocchetti G, Bonini P, Tabaglio V, Lucini L. A response surface methodology approach to improve nitrogen use efficiency in maize by an optimal mycorrhiza-to- Bacillus co-inoculation rate. FRONTIERS IN PLANT SCIENCE 2022; 13:956391. [PMID: 36035726 PMCID: PMC9404334 DOI: 10.3389/fpls.2022.956391] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 05/30/2022] [Accepted: 07/11/2022] [Indexed: 06/15/2023]
Abstract
Co-inoculation of arbuscular mycorrhizal fungi (AMF) and bacteria can synergically and potentially increase nitrogen use efficiency (NUE) in plants, thus, reducing nitrogen (N) fertilizers use and their environmental impact. However, limited research is available on AMF-bacteria interaction, and the definition of synergisms or antagonistic effects is unexplored. In this study, we adopted a response surface methodology (RSM) to assess the optimal combination of AMF (Rhizoglomus irregulare and Funneliformis mosseae) and Bacillus megaterium (a PGPR-plant growth promoting rhizobacteria) formulations to maximize agronomical and chemical parameters linked to N utilization in maize (Zea mays L.). The fitted mathematical models, and also 3D response surface and contour plots, allowed us to determine the optimal AMF and bacterial doses, which are approximately accorded to 2.1 kg ha-1 of both formulations. These levels provided the maximum values of SPAD, aspartate, and glutamate. On the contrary, agronomic parameters were not affected, except for the nitrogen harvest index (NHI), which was slightly affected (p-value of < 0.10) and indicated a higher N accumulation in grain following inoculation with 4.1 and 0.1 kg ha-1 of AMF and B. megaterium, respectively. Nonetheless, the identification of the saddle points for asparagine and the tendency to differently allocate N when AMF or PGPR were used alone, pointed out the complexity of microorganism interaction and suggests the need for further investigations aimed at unraveling the mechanisms underlying this symbiosis.
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Affiliation(s)
- Paola Ganugi
- Department for Sustainable Food Process, Università Cattolica del Sacro Cuore, Piacenza, Italy
| | - Andrea Fiorini
- Department of Sustainable Crop Production, Università Cattolica del Sacro Cuore, Piacenza, Italy
| | - Gabriele Rocchetti
- Department of Animal Science, Food and Nutrition, Università Cattolica del Sacro Cuore, Piacenza, Italy
| | | | - Vincenzo Tabaglio
- Department of Sustainable Crop Production, Università Cattolica del Sacro Cuore, Piacenza, Italy
| | - Luigi Lucini
- Department for Sustainable Food Process, Università Cattolica del Sacro Cuore, Piacenza, Italy
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Omomowo OI, Babalola OO. Constraints and Prospects of Improving Cowpea Productivity to Ensure Food, Nutritional Security and Environmental Sustainability. FRONTIERS IN PLANT SCIENCE 2021; 12:751731. [PMID: 34745184 PMCID: PMC8570086 DOI: 10.3389/fpls.2021.751731] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/01/2021] [Accepted: 09/30/2021] [Indexed: 05/23/2023]
Abstract
Providing safe and secure food for an increasing number of people globally is challenging. Coping with such a human population by merely applying the conventional agricultural production system has not proved to be agro-ecologically friendly; nor is it sustainable. Cowpea (Vigna unguiculata (L) Walp) is a multi-purpose legume. It consists of high-quality protein for human consumption, and it is rich in protein for livestock fodder. It enriches the soil in that it recycles nutrients through the fixation of nitrogen in association with nodulating bacteria. However, the productivity of this multi-functional, indigenous legume that is of great value to African smallholder farmers and the rural populace, and also to urban consumers and entrepreneurs, is limited. Because cowpea is of strategic importance in Africa, there is a need to improve on its productivity. Such endeavors in Africa are wrought with challenges that include drought, salinity, the excessive demand among farmers for synthetic chemicals, the repercussions of climate change, declining soil nutrients, microbial infestations, pest issues, and so forth. Nevertheless, giant strides have already been made and there have already been improvements in adopting sustainable and smart biotechnological approaches that are favorably influencing the production costs of cowpea and its availability. As such, the prospects for a leap in cowpea productivity in Africa and in the enhancement of its genetic gain are good. Potential and viable means for overcoming some of the above-mentioned production constraints would be to focus on the key cowpea producer nations in Africa and to encourage them to embrace biotechnological techniques in an integrated approach to enhance for sustainable productivity. This review highlights the spectrum of constraints that limit the cowpea yield, but looks ahead of the constraints and seeks a way forward to improve cowpea productivity in Africa. More importantly, this review investigates applications and insights concerning mechanisms of action for implementing eco-friendly biotechnological techniques, such as the deployment of bio inoculants, applying climate-smart agricultural (CSA) practices, agricultural conservation techniques, and multi-omics smart technology in the spheres of genomics, transcriptomics, proteomics, and metabolomics, for improving cowpea yields and productivity to achieve sustainable agro-ecosystems, and ensuring their stability.
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Saini I, Kaushik P, Al-Huqail AA, Khan F, Siddiqui MH. Effect of the diverse combinations of useful microbes and chemical fertilizers on important traits of potato. Saudi J Biol Sci 2021; 28:2641-2648. [PMID: 34025148 PMCID: PMC8117242 DOI: 10.1016/j.sjbs.2021.02.070] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2021] [Revised: 02/18/2021] [Accepted: 02/21/2021] [Indexed: 11/16/2022] Open
Abstract
The belowground soil environment is an active space for microbes, particularly Arbuscular Mycorrhizal Fungi (AMF) and P hosphate Solubilizing Bacteria (PSB) that can colonize with roots of higher plants. In the present experiment, we evaluated the combination of microbial inoculants with the different doses of urea and superphosphate in a complete randomized block design (CRBD). Three different doses of urea and superphosphate were tested, i.e., recommended dose, 75% of the recommended dose and 125% of the recommended dose, independently and in combination with three microbial groups viz. Glomus mosseae (AMF), Bacillus subtilis (PSB) and Nitrifying microorganisms (Nitrosomonas + Nitrobacter, NN). Overall, there were 16 treatment combinations used, and studied the number of tubers per plant, the weight of tubers, moisture content, and the number of nodes per tubers which were best in treatment comprising of AMF + PSB + NN + 75% of urea + superphosphate. From our results, it is suggested for the growers to use a lesser quantity of fertilizers from the recommended dose along with some bioinoculants to maintain the soil fertility and also to achieve the yield targets by decreasing the cost of chemical fertilizers.
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Affiliation(s)
- Ishan Saini
- Department of Botany, Kurukshetra University Kurukshetra, Kurukshetra 136119, India
| | - Prashant Kaushik
- Instituto de Conservación y Mejora de la Agrodiversidad Valenciana, Universitat Politècnica de València, 46022 Valencia, Spain
| | - Asma A Al-Huqail
- Department of Botany and Microbiology, College of Science, King Saud University, Riyadh 11451, Saudi Arabia
| | - Faheema Khan
- Department of Botany and Microbiology, College of Science, King Saud University, Riyadh 11451, Saudi Arabia
| | - Manzer H Siddiqui
- Department of Botany and Microbiology, College of Science, King Saud University, Riyadh 11451, Saudi Arabia
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