Prospección y caracterización de microorganismos psicrófilos y psicrotolerantes promotores del crecimiento vegetal aislados del volcán xinantécatl

Abstract. With the goal of finding sustainable solutions for the use of agrochemicals, we devoted to the isolation of psychrophile and psychrotolerant Plant Growth Promoting Microorganisms (PGPM). Eighth yeast and four bacterial strains were isolated from soil collected at the glacier of the Xinantécatl volcano in Mexico and characterized for Plant Growth Promoting characteristics. Most of the yeast produced Indole Acetic Acid and hydrolytic enzymes (CMCases, xilanases, and chitinases), but none of them produced siderophores, in contrast with their bacterial counterparts. Inorganic phosphate solubilization was detected for all the bacterial strains and for in two yeast strains. The microorganisms were identified to the genera level using ribotyping techniques and phylogenetic analysis. Bacterial strains belonged to the genus Pseudomonas, while the yeast strains were Rhodotorula sp (4), Mrakiella sp. (3), and Naganishia sp (1). Plant growth promoting activity on Solanum lycopersicum plants was detected for yeast strains with respect to a control in MS media only. This study opens the possibility to use these strains as an additive to improve the culture conditions of S. lycopersicum in a more environmental friendly way.