Phosphorus Nutrition and Growth of Cotton Plants Inoculated With Growth-Promoting Bacteria Under Low Phosphate Availability

Felipe Romero-Perdomo,Jonathan Mendoza-Labrador,Ruth Bonilla,Isidro Beltrán,German Estrada-Bonilla

doi:10.3389/fsufs.2020.618425

Felipe Romero-Perdomo, Jonathan Mendoza-Labrador + Show 3 more

Open Access

https://doi.org/10.3389/fsufs.2020.618425

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Abstract

The low availability of phosphorus (P) in the soil drastically limits the world productivity of crops such as cotton. In order to contribute sustainably to the solution of this problem, the current study aimed to evaluate the capacity of phosphate-solubilising bacteria to improve plant growth and its relationship with physiological parameters, as well as the shoot P content in cotton plants in a soil with low P availability amended with rock phosphate. The results showed that, of the six plant growth-promoting bacteria strains evaluated under greenhouse conditions, the Rhizobium strain B02 significantly promoted growth, shoot P content and photosynthetic rate. This strain also improved the transpiration rate and the relative content of chlorophyll but without significant differences. Remarkably, Rhizobium sp. B02 had a more significant effect on plant growth compared to the P nutrition. Furthermore, the effect of its inoculation was more pronounced on the roots' growth compared to the shoot. Finally, application of Rhizobium strain B02 showed the capacity to optimize the use of low-solubility fertilizer as the rock phosphate. These findings could be associated with the metabolic activities of plant growth promotion exhibited by phosphate-solubilising strains, such as phosphate solubilisation, production of indole compounds and siderophores synthesis. In conclusion, this research provides evidence of the biotechnological potential of the Rhizobium genus as phosphate-solubilising bacteria with multiple plant growth-promoting activities capable of improving the plant growth and phosphate nutrition of non-leguminous crops such as cotton in soil with low P availability amended with rock phosphate.

Highlights

Phosphorus (P) is an essential element for various plant metabolic processes and contributes to the formation of cellular biomolecules such as adenosine triphosphate (ATP), nucleic acids and proteins (Heuer et al, 2017)
P is derived from finite resources such as P-rich rock in the form of plant growth-promoting bacteria (PGPB) in Cotton Phosphorus Nutrition phosphate, which has been 83% exploited in its world reserves (Magallon-Servín et al, 2019)
The application of the diammonium phosphate (DAP) fertilizer had a more positive impact on all the parameters measured in cotton plants than rock phosphate (RP) in the absence of PGPB inoculation

Summary

Introduction

Phosphorus (P) is an essential element for various plant metabolic processes and contributes to the formation of cellular biomolecules such as adenosine triphosphate (ATP), nucleic acids and proteins (Heuer et al, 2017). P is derived from finite resources such as P-rich rock in the form of PGPB in Cotton Phosphorus Nutrition phosphate, which has been 83% exploited in its world reserves (Magallon-Servín et al, 2019). Despite this problem, regular applications of phosphate fertilizers are required to maintain crop yields; its application is increasing rapidly— around 2.5% per year under intensified agriculture due to the growing demand for food (Bashan et al, 2013). New strategies to improve the efficiency of the use of phosphate fertilizers and reduce their application, while maintaining high cotton crop yields, have become one of the greatest challenges in Colombia

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