Phosphorus solubilizing bacteria isolated from the rhizosphere of wild potato Solanum bulbocastanum enhance growth of modern potato varieties

Authors: PANTIGOSO, HUGO - Colorado State University; HE, YANHUI - Shihezi University; Manter, Daniel; FONTE, STEVEN - Colorado State University; VIVANCO, JORGE - Colorado State University

Submitted to: Genetics, Genomics and Breeding of Potatoes
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 7/7/2022
Publication Date: 7/28/2022
Citation: Pantigoso, H.A., He, Y., Manter, D.K., Fonte, S.J., Vivanco, J.M. 2022. Phosphorus solubilizing bacteria isolated from the rhizosphere of wild potato Solanum bulbocastanum enhance growth of modern potato varieties. Genetics, Genomics and Breeding of Potatoes. 46. Article e224. https://doi.org/10.1186/s42269-022-00913-x.
DOI: https://doi.org/10.1186/s42269-022-00913-x

Interpretive Summary: Phosphorus (P) is a fundamental element for all organisms and an essential nutrient for agricultural production. The availability of P in soils is limited by soil sorption and the formation of insoluble complexes of P requiring substantially higher P fertilizer rates than required by the crop for normal growth. Wild species of crops tend to have diverse mechanisms for acquiring P in their native habitats, including the recruitment of rhizosphere microbes involved in nutrient solubilization. In this study we isolated Enterobacter sp., Bacillus sp. and Pseudomonas sp. from the rhizosphere of the wild potato Solanum bulbocastanum grown under greenhouse conditions and characterized their P-solubilizing activities. Both individual bacterial species and the consortium of the three bacteria dissolved organic (i.e. phytin) and inorganic P (i.e. calcium phosphate) in vitro. Interestingly, the bacteria consortium increased dissolved P by 36-fold for calcium phosphate and 13-fold for phytin surpassing the effect of each individual P-solubilizing bacteria (PSB) strain. To further evaluate the effect of the PSB consortia on plant growth and P use efficiency, the bacteria were co-inoculated to a commercial potato cultivar and amended separately with phytin, calcium phosphate, commercial P fertilizer, or a combination of the three P sources. Our results showed an overall increase in plant dry biomass and shoot P content for plant available (i.e. triple super phosphate) and plant unavailable (i.e. calcium phosphate) P in treatments co-inoculated with all PSB. The effect of P sources and PSB consortia inoculation on shoot P uptake and utilization efficiencies revealed a clear treatment difference due to PSB application. In summary, these results demonstrate the ability of PSB isolated from wild plants to enhance crop P nutrition and their potential to increase availability of sparingly soluble forms of P in soils, thereby increasing crop yield and reducing P fertilizer inefficiencies.

Technical Abstract: Wild species of crops tend to have diverse mechanisms for acquiring P in their native habitats, including the recruitment of rhizosphere microbes involved in nutrient solubilization. In this study we isolated Enterobacter sp., Bacillus sp. and Pseudomonas sp. from the rhizosphere of the wild potato Solanum bulbocastanum grown under greenhouse conditions and characterized their P-solubilizing activities. Both, individual bacterial species and the consortium of the three bacteria, dissolved organic (i.e. phytin) and inorganic P (i.e. calcium phosphate) in vitro. Interestingly, the bacteria consortium increased dissolved P by 36-fold for calcium phosphate and 13-fold for phytin surpassing the effect of each individual P-solubilizing bacteria (PSB) strain. To further evaluate the effect of the PSB consortia on plant growth and P use efficiency, the bacteria were co-inoculated to a commercial potato cultivar and amended separately with phytin, calcium phosphate, commercial P fertilizer, or a combination of the three P sources. Our results showed an overall increase in plant dry biomass and shoot P content for plant available (i.e. triple super phosphate) and plant unavailable (i.e. calcium phosphate) P in treatments co-inoculated with all PSB. The effect of P sources and PSB consortia inoculation on shoot P uptake and utilization efficiencies revealed a clear treatment difference due to PSB application. In summary, these results demonstrate the ability of PSB isolated from wild plants to enhance crop P nutrition and their potential to increase availability of sparingly soluble forms of P in soils, thereby increasing crop yield and reducing P fertilizer inefficiencies.