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Role of rhizosphere bacteria and root exudates on the assimilation of phosphorus

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dc.contributor.authorPantigoso Guevara, Hugo A., author
dc.contributor.authorVivanco, Jorge M., advisor
dc.contributor.authorFonte, Steven, committee member
dc.contributor.authorDavis, Jessica, committee member
dc.contributor.authorManter, Daniel, committee member
dc.date.accessioned2022-05-30T10:22:25Z
dc.date.available2022-05-30T10:22:25Z
dc.date.issued2022
dc.description.abstractDeficient phosphorus (P) bioavailability in soils is a major challenge for sustainable food production as effective strategies to access unavailable P are limited. Solubilizing-bacteria and root exudate metabolites that solubilize P are promising approaches to increase available P for plants. We hypothesized that compounds in root exudates could elicit the P-solubilization activity of bacteria. To test this hypothesis, the root exudates of Arabidopsis grown in vitro under sufficient and deficient P conditions were characterized using GC-MS. We tested the ability of previously screened root exudates to solubilize plant-unavailable P in vitro. In parallel, potential P-solubilizing bacteria were isolated from the rhizosphere of wild potatoes using conventional microbiology techniques. The bacteria strains were tested, both individually and in consortia, for their ability to solubilize organic (phytin) and inorganic (calcium) P sources in vitro and in planta. Lastly, selected root exudate compounds were incubated together with P-solubilizing bacteria, and bacterial growth, P solubilization activity, and plant growth were evaluated. Our results demonstrate that malic, nicotinic, and 3-hydroxypropionic acids improved solubilization of P as compared to a control. Likewise, the bacterial strains E. cloacae, P. pseudoalcaligenes, and B. thuringiensis enhanced plant growth and P content with additions of plant-unavailable P. Furthermore, we found that threonine and 4-hydroxybutyric acid elicit P solubilization in all bacteria, under both organic and inorganic sources, independent of bacterial growth. Subsequent exogenous application of threonine to soils improved plant root growth, enhanced nitrogen and phosphorus content in roots and increased available levels of potassium, calcium, and magnesium in soils. Altogether, our findings expand on the function of exuded specialized compounds and suggest approaches to effectively recover residual P from soil, improving crop growth and nutrition.
dc.format.mediumborn digital
dc.format.mediumdoctoral dissertations
dc.identifierPantigosoGuevara_colostate_0053A_17024.pdf
dc.identifier.urihttps://hdl.handle.net/10217/235267
dc.languageEnglish
dc.language.isoeng
dc.publisherColorado State University. Libraries
dc.relation.ispartof2020-
dc.rightsCopyright and other restrictions may apply. User is responsible for compliance with all applicable laws. For information about copyright law, please see https://libguides.colostate.edu/copyright.
dc.subjectplant
dc.subjectrhizosphere
dc.subjectsoil
dc.subjectrhizobacteria
dc.subjectphosphorus
dc.subjectroot exudates
dc.titleRole of rhizosphere bacteria and root exudates on the assimilation of phosphorus
dc.typeText
dcterms.rights.dplaThis Item is protected by copyright and/or related rights (https://rightsstatements.org/vocab/InC/1.0/). You are free to use this Item in any way that is permitted by the copyright and related rights legislation that applies to your use. For other uses you need to obtain permission from the rights-holder(s).
thesis.degree.disciplineHorticulture & Landscape Architecture
thesis.degree.grantorColorado State University
thesis.degree.levelDoctoral
thesis.degree.nameDoctor of Philosophy (Ph.D.)

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