Sustainable Food Production Systems for Climate Change Mitigation: Indigenous Rhizobacteria for Potato Bio-fertilization in Tanzania (original) (raw)
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Using Plant Growth Promoting Rhizobacteria to Improve Potato Production and Plant Health
Plant Growth Promoting Rhizobacteria (PGPR) have shown their potential in various crops to improve yield and plant health. In this respect PGPR could be developed into an alternative inexpensive bio-fertilizer to increase potato yields of small scale subsistence farmers and/or to improve organic crop production systems in the Central Andean Highlands of Peru. In 2005/06 commercially available PGPR were applied in field trails with potatoes, resulting in yield increases of 20-30% and partial control of Rhizoctonia solani. Increased yields were due to greater sink size and sink strength of the inoculated potato crop. Populations of Azotobacter and Bacillus subtilis in the rhizosphere of the potato were greater during the entire growth period as compared with non-inoculated control potato plants. Based on these results PGPR research will be continued and native bacteria in the major potatogrowing regions of Peru will be sampled, identified, tested and selected. PGPR shows a clear potential to increase nutrient use efficiency of potato that could be developed as an important element in low and high input crop production systems.
Evaluating soil rhizobacteria for their ability to enhance plant growth and tuber yield in potato
Annals of Applied Biology, 2010
The objectives of this study were to identify promising microorganisms to improve potato productivity in low-input systems of tropical highlands and to compare results from in vitro, greenhouse and field experiments to advance the development of a screening method for rhizobacteria and develop an efficient assessment of their effect on plant growth in field conditions. A total of 150 bacterial strains were screened in vitro, in greenhouse and field trials. The series of experiments confirmed the plant growth-promoting ability of a range of rhizobacteria. Although in vitro and greenhouse results were promising, the field experiment showed variability and the results require further verification. The in vitro tests might have limited value for screening as no correlation could be found between in vitro tests and pot trial results. However, trials in controlled conditions produced insights into the mechanisms causing better plant growth in potato, such as early tuberisation, fast development of leaf area and probably greater photosynthetic rates.
Rhizobacteria-Based Technology for Sustainable Cropping of Potato (Solanum tuberosum L.)
Potato Research, 2019
Potato (Solanum tuberosum L.) is one of the most important food crops worldwide but its cultivation is affected by numerous challenges including pests, diseases and high fertiliser requirements which have associated environmental problems. The exploitation of plant rhizospheres and their associated rhizobacterial interactions has gathered momentum worldwide in search of environmentally-friendly approaches to crop cultivation. A lot of literature exists on rhizobacterial associations and their biofertilisation or bioprotection roles in many plants. However, very scanty information is available on rhizobacterial functions and communities of the potato, an indication that they are still understudied. In this regard, more research is needed to understand and exploit them for the successful application of rhizobacteria-based technology in potato cropping. This review updates our knowledge of the beneficial rhizobacteria of the potato and documents their roles in its bioprotection, phytostimulation and biofertilisation while highlighting their potential in enhancing its production and productivity. The future prospects regarding the research on these important potato microflora are further discussed as a guide and a baseline for future research on them. This review shows that rhizobacteria-based technology is a viable option for potato biofertilisation and bioprotection and could be the missing link in its sustainable cropping. The adoption and full exploitation of this technology can be fast-tracked if we increase our understanding of the subject matter.
Frontiers in plant science, 2016
Rhizosphere engineering with beneficial plant growth promoting bacteria offers great promise for sustainable crop yield. Potato is an important food commodity that needs large inputs of nitrogen and phosphorus fertilizers. To overcome high fertilizer demand (especially nitrogen), five bacteria, i.e., Azospirillum sp. TN10, Agrobacterium sp. TN14, Pseudomonas sp. TN36, Enterobacter sp. TN38 and Rhizobium sp. TN42 were isolated from the potato rhizosphere on nitrogen-free malate medium and identified based on their 16S rRNA gene sequences. Three strains, i.e., TN10, TN38, and TN42 showed nitrogen fixation (92.67-134.54 nmol h(-1)mg(-1) protein), while all showed the production of indole-3-acetic acid (IAA), which was significantly increased by the addition of L-tryptophan. Azospirillum sp. TN10 produced the highest amount of IAA, as measured by spectrophotometry (312.14 μg mL(-1)) and HPLC (18.3 μg mL(-1)). Inoculation with these bacteria under axenic conditions resulted in differenti...
Effect of Rhizobacterial Strain Enterobacter Cloacae Strain Pglo 9 on Potato Plant Growth and Yield
2018
To assess functional potentialities of rhizobacteria in relation to plant growth promoting activities, rhizobacterial strain Enterobacter cloacae PGLO9 was obtained from rhizosphere soil of potato plant (Solanum tuberosum L.) root. The result of in vitro assays showed that strain PGLO9 solubilize phosphate as well as produce siderophore and amylase. This strain having abilities for phosphate solubilization, siderophores and amylase production, were tested as bioinoculant to potato tubers via pot trail experiment. The results of inoculated potato plants showed significant increase in vegetative growth parameters such as root length, shoot length, root biomass and shoot biomass, compared with control and found better response in potato plant growth and yield against uninoculated control. Whereas potatoes harvested was healthy as well as not infected with any pathogen. Strain PGLO9 can be recommended as biofertilizer for reducing the dependence on chemical fertilizers and providing a s...
Effect of Site and Phenological Status on the Potato Bacterial Rhizomicrobiota
Microorganisms
The potato is the fourth major food crop in the world. Its cultivation can encounter problems, resulting in poor growth and reduced yield. Plant microbiota has shown an ability to increase growth and resistance. However, in the development of effective microbiota manipulation strategies, it is essential to know the effect of environmental variables on microbiota composition and function. Here, we aimed to identify the differential impact of the site of cultivation and plant growth stage on potato rhizosphere microbiota. We performed a 16S rRNA gene amplicon sequencing analysis of rhizospheric soil collected from potato plants grown at four sites in central Italy during two phenological stages. Rhizomicrobiota was mainly composed of members of phyla Acidobacteriota, Actinobacteriota, Chloroflexi, and Proteobacteria and was affected by both the site of cultivation and the plant stages. However, cultivation sites overcome the effect of plant phenological stages. The PiCRUST analysis su...
Food security (a pressing issue for all nations) faces a threat due to population growth, land availability for growing crops, a changing climate (leading to increases in both abiotic and biotic stresses), heightened consumer awareness of the risks related to the use of agrichemicals, and also the reliance on depleting fossil fuel reserves for their production. Legislative changes in Europe mean that fewer agrichemicals will be available in the future for the control of crop pests and pathogens. The need for the implementation of a more sustainable agricultural system globally, incorporating an integrated approach to disease management, has never been more urgent. To that end, the Valorizing Andean Microbial Diversity (VALORAM) project (http://valoram.ucc.ie), funded under FP7, examined the role of microbial communities in crop production and protection to improve the sustainability, food security, environmental protection, and productivity for rural Andean farmers. During this work, microbial volatile organic compounds (mVOCs) of 27 rhizobacterial isolates were identified using gas chromatography/mass spectrometry (GC/MS), and their antifungal activity against Rhizoctonia solani was determined in vitro and compared to the activity of a selection of pure volatile compounds. Five of these isolates, Pseudomonas palleroniana R43631, Bacillus sp. R47065, R47131, Paenibacillus sp. B3a R49541, and Bacillus simplex M3-4 R49538 trialled in the field in their respective countries of origin, i.e., Bolivia, Peru, and Ecuador, showed significant increase in the yield of potato. The strategy followed in the VALORAM project may offer a template for the future isolation and determination of putative biocontrol and plant growth-promoting agents, useful as part of a low-input integrated pest management system.
Microbiotic biodiversity and their functionality in roots and rhizosphere of potato plants
ISTRC Tropical Roots and …, 2009
Soil microbiotic biodiversity plays an important role and fulfills diverse functions for the growth and development of plants and crops. Its beneficial effects include among others the control of soil pathogens, the supply and utilization of nutrients and/or soil moisture. In 2008 rhizosphere populations of bacteria and fungi of 12 different potato fields in 4 provinces in the Andean highlands of Peru were analyzed and possible PGPR (promoting growth rhizobacteria) genera were isolated from the root surface, the root interior (endophytic) and the rhizosphere. Total bacteria counts in the rhizosphere seemed to be influenced by altitude and soil electric conductivity. The rhizosphere populations of microorganism seems to be adapted to this micro-enviorenment so, even though the external conditions are extreme the rhizosphere acts like a support zone for the microbial development. We found the active presence of bacteria form the Azospirillum, Azotobacter, Pseudomonas and Actinomycetes genera even in low pH and temperature conditions and different inputs levels. We isolated a total of 62 Azotobacter strains, 45 Actinomycetes, 68 Pseudomonas and 55 Azospirillum from the surface of roots, their interior or the rhizosphere soil. The active presence of total bacteria and potential PGPR genera in the potato rhizosphere represents an important part to understand the influence of microorganism in this microenvironment and the possible relation with the plant development.
American Journal of Potato Research, 2012
The objective of this study was to isolate and characterize genera of bacteria that had been identified as being the most common residents in the rhizosphere of potato using cpn60 pyrosequencing analysis. Using various semiselective media targeted to specific genera of interest, 200 isolates of bacteria were collected from rhizosphere soil and the rhizoplane of potatoes grown in soils obtained from a potato farm in Prince Edward Island and Ontario. The procedures employed were successful in selecting out representative bacteria suggested by pyrosequencing to be common in the potato rhizoplane. Results of 16S rRNA sequencing showed that 44 % of the isolates represented new species. All isolates were tested for biological and biochemical activities including phosphate solubilization, phytohormone metabolism, nitrogen fixation, antibiosis, exoenzyme production, and production of acyl-homoserine lactones. Massilia spp. and Chryseobacterium spp. showed the strongest exoenzyme activities. A greater proportion of Agrobacterium tumefaciens rhizosphere strains produced acyl-homoserine lactones compared to rhizoplane strains. Pseudomonas spp. and Lysobacter capsici had the greatest antagonistic activity on laboratory media towards six potato pathogens, and also significantly decreased disease in plants grown in pathogen-infested soil. Four isolates significantly increased growth of potato nodal explants in tissue culture. By using preliminary results derived from next generation sequencing technology and a targeted cultural technique, we were able to gain a better understanding of the biological activities of the most abundant bacterial species in the rhizosphere and rhizoplane of a cultivated crop.