Dataset Information

Characterization of Phosphate Solubilizing Bacterial Endophytes and Plant Growth Promotion In Vitro and in Greenhouse.

ABSTRACT: Phosphate is one of the most important nutrients for plant growth and development, and only 0.1% of the phosphate in soils is available to plants. Currently, the use of excess phosphate fertilizer has caused surface and ground water pollution and water eutrophication, resulting in algal blooms in lakes and oceans. Therefore, it is imperative to explore alternative ways to solve these problems for sustainable agricultural production and improvement of soil fertility, while protecting the environment. Microorganisms from the rhizosphere and within plants are able to solubilize insoluble soil phosphate, making it available to plants. Five high phosphate solubilizing bacteria from our bacterial endophyte library were chosen for this study and identified as Pantoea vagans IALR611, Pseudomonas psychrotolerans IALR632, Bacillus subtilis IALR1033, Bacillus safensis IALR1035 and Pantoea agglomerans IALR1325. All five bacteria significantly promoted tall fescue growth in vitro. Greenhouse experiments showed that IALR1325 significantly promoted pepper and tomato growth, and IALR632 was the best in promoting tomato growth. In addition, all these bacteria had extracellular acid phosphatase and phytase activities. One of the mechanisms for phosphate solubilization by bacteria is pH reduction caused by gluconic acid production. Our results indicate that P. agglomerans IALR1325 is a promising bacterium for future applications.

SUBMITTER: Mei C

PROVIDER: S-EPMC8469958 | biostudies-literature |

REPOSITORIES: biostudies-literature

ACCESS DATA

Similar Datasets

Project description:Most agricultural soils are facing limited phosphorus availability that challenges modern agriculture. Phosphate solubilizing microbia (PSM) has been explored extensively as potential biofertilizers for plant growth and nutrition, and harnessing phosphate rich areas could provide such beneficial microorganisms. Isolation of PSM from Moroccan rock phosphate led to the selection of two bacterial isolates, Bg22c and Bg32c, showing high solubilization potential. The two isolates were also tested for other in vitro PGPR effects and compared to a non-phosphate solubilizing bacterium Bg15d. In addition to phosphates, Bg22c and Bg32c were able to solubilize insoluble potassium and zinc forms (P, K, and Zn solubilizers) and produce indole-acetic acid (IAA). Mechanisms of solubilization involved production of organic acids as demonstrated by HPLC. In vitro, the isolates Bg22c and Bg15d were able to antagonize the phytopathogenic bacteria Clavibacter michiganensis subsp. michiganensis, causal agent of tomato bacterial canker disease. Phenotypic and molecular identification by 16S rDNA sequencing demonstrated delineation of Bg32c and Bg15d as members of the genus Pseudomonas and Bg22c as member of the genus Serratia. The two isolates Bg22c and Bg32c were further tested either alone or in a consortium and compared to the non-P, K, and Zn solubilizing Pseudomonas strain Bg15d for their efficacy to promote tomato growth and yield. They were also compared to treatment with a conventional NPK fertilizer. Under greenhouse conditions, Pseudomonas strain Bg32c remarkably improved the growth of whole plant height, root length, shoot and root weight, number of leaves and fruits, as well as fruit fresh weight. This strain also induced stomatal conductance enhancement. The strain also improved total soluble phenolic compounds, total sugars, protein, phosphorus and phenolic compounds contents compared to the negative control. All increases were more pronounced in plants inoculated with strain Bg32c in comparison with control and strain Bg15d. The strain Bg32c could be considered a potential candidate for formulation of a biofertilizer in order to improve tomato growth.

Project description:BackgroundRice (Oryza sativa L. ssp. indica) seeds as plant microbiome present both an opportunity and a challenge to colonizing bacterial community living in close association with plants. Nevertheless, the roles and activities of bacterial endophytes remain largely unexplored and insights into plant-microbe interaction are compounded by its complexity. In this study, putative functions or physiological properties associated with bacterial endophytic nature were assessed. Also, endophytic roles in plant growth and germination that may allow them to be selectively chosen by plants were also studied.ResultsThe cultivable seed endophytes were dominated by Proteobacteria particularly class Gammaproteobacteria. Highly identical type strains were isolated from the seed endosphere regardless of the rice host's physiological tolerance to salinity. Among the type strains, Flavobacterium sp., Microbacterium sp. and Xanthomonas sp. were isolated from the salt-sensitive and salt-tolerant cultivars. PCA-Biplot ordination also showed that specific type strains isolated from different rice cultivars have distinguishing similar characteristics. Flavobacterium sp. strains are phosphate solubilizers and indole-3-acetic acid producers with high tolerance to salinity and osmotic stress. Pseudomonas strains are characterized as high siderophore producers while Microbacterium sp. and Xanthomonas sp. strains have very high pectinase and cellulase activity. Among the physiological traits of the seed endophytes, bacterial pectinase and cellulase activity are positively correlated as well as salt and osmotic tolerance. Overall characterization shows that majority of the isolates could survive in 4-8% salt concentration as well as in 0.6 M and 1.2 M sucrose solution. The activities of catalase, pectinase and cellulase were also observed in almost all of the isolates indicating the importance of these characteristics for survival and colonization into the seed endosphere. Seed bacterial endophytes also showed promising plant growth promoting activities including hormone modulation, nitrogen fixation, siderophore production and phosphate solubilization.ConclusionThough many of the isolates possess similar PGP and endophytic physiological traits, this study shows some prominent and distinguishing traits among bacterial groups indicating key determinants for their success as endophytes in the rice seed endosphere. Rice seeds are also inhabited by bacterial endophytes that promote growth during early seedling development.

Project description:Recently, the application of endophytes in the alleviation of different types of stresses has received considerable attention, but their role in drought stress alleviation and growth promotion in soybean is not well-stated. In this study, twenty bacterial endophytes were isolated from soybean root tissues and screened for plant growth-promoting (PGP) traits, biocontrol potential, and drought stress alleviation. Out of them, 80% showed PGP traits, and 20% showed antagonistic activity against Fusarium oxysporum (ITCC 2389), Macrophomina phaseolina (ITCC 1800), and Alternaria alternata (ITCC 3467), and only three of them showed drought tolerance up to 15% (-0.3 MPa). Results indicated that drought-tolerant PGP endophytic bacteria enhanced soybean seedling growth under drought stress conditions. Morphological, biochemical, and molecular characterization (16S rRNA) revealed that these three bacterial isolates, AKAD A1-1, AKAD A1-2, and AKAD A1-16, closely resemble Bacillus cereus (GenBank accession No. MN079048), Pseudomonas otitidis (MW301101), and Pseudomonas sp. (MN079074), respectively. We observed that the soybean seedlings were grown in well-watered and drought-stressed soil showed the adverse effect of drought stress on morphological (stem length, root length, plant fresh and dry weight) as well as on biochemical parameters (a decline of photosynthetic pigments, membrane damage, etc.). However, soybean seedlings inoculated with these endophytes have improved the biomass significantly (p ? 0.05) under normal as well as in drought stress conditions over control treatments by influencing several biochemical changes. Among these three endophytes, AKAD A1-16 performed better than AKAD A1-2 and AKAD A1-1, which was further validated by the ability to produce the enzyme 1-aminocyclopropane-1-carboxylate (ACC) deaminase in the following order: AKAD A1-16 > AKAD A1-2 > AKAD A1-1. Scanning electron microscopy images also showed a bacterial presence inside the roots of soybean seedlings. These findings supported the application of bacterial root endophytes as a potential tool to mitigate the effect of drought as well as of fungal diseases on the early seedling growth of soybean.

Dataset Information

Characterization of Phosphate Solubilizing Bacterial Endophytes and Plant Growth Promotion In Vitro and in Greenhouse.

Similar Datasets

OmicsDI is part of the ELIXIR infrastructure

Tweets