Identification of rhizobial strains nodulating Pisum Sativum in northern spain soils by MALDI-TOF MS (matrix-assisted laser desorption ionization time-of-flight mass spectrometry) analysis

Abstract

In this work, we used MALDI-TOF MS for identification of strains nodulating Pisum sativum L. (peas) in soils from Valladolid, Salamanca and León where the 30 % of the total Spanish production of peas is located. The results obtained showed a correct identification, with score values higher than 2.0, of strains isolated in the soil from León as Rhizobium leguminosarum and those isolated in soils from Valladolid and Salamanca as Rhizobium laguerreae. These results confirmed that MALDI-TOF MS is a reliable technique for identification at species level of fast-growing rhizobia. They also showed that this methodology is able to differentiate between sister species, not distinguishable on the basis of 16S rRNA gene analysis, as occurs in the case of R. leguminosarum and R. laguerreae.