Probiotic activities of Rhizobium laguerreae on growth and quality of spinach

10 páginas, 4 figuras y 2 tablas

The growing interest in a healthy lifestyle and in environmental protection is changing habits regarding food consumption and agricultural practices. Good agricultural practice is indispensable, particularly for raw vegetables, and can include the use of plant probiotic bacteria for the purpose of biofertilization. In this work we analysed the probiotic potential of the rhizobial strain PEPV40, identified as Rhizobium laguerreae through the analysis of the recA and atpD genes, on the growth of spinach plants. This strain presents several in vitro plant growth promotion mechanisms, such as phosphate solubilisation and the production of indole acetic acid and siderophores. The strain PEPV40 produces cellulose and forms biofilms on abiotic surfaces. GFP labelling of this strain showed that PEPV40 colonizes the roots of spinach plants, forming microcolonies typical of biofilm initiation. Inoculation with this strain significantly increases several vegetative parameters such as leaf number, size and weight, as well as chlorophyll and nitrogen contents. Therefore, our findings indicate, for the first time, that Rhizobium laguerreae is an excellent plant probiotic, which increases the yield and quality of spinach, a vegetable that is increasingly being consumed raw worldwide.

This work was supported by Grants SA169U14 and SA058U16 from the Regional Government of Castile and Leon, and AGL2015–70510-R from MINECO (Spanish Ministry of Economy, Industry and Competitiveness). AJG is the recipient of a FPU predoctoral fellowship from the Central Spanish Government, JDFF is the recipient of a predoctoral fellowship from Salamanca University. PGF receives funding from the European Union’s Horizon 2020 research and innovation programme under grant agreement No. 750795. The authors also thank Emma Keck, translator at the Language Centre of the University of Salamanca.

Peer reviewed