Physiological adaptations in Lactobacillus paraplantarum CRL 1905 induced by differential concentrations of phosphate in the medium

ARAOZ, MARIO; GRILLO PUERTAS, MARIANA; HEBERT, ELVIRA MARIA; INTERDONATO, ROQUE; VILLEGAS, JOSEFINA MARÍA; RAPISARDA, VIVIANA ANDREA

Congreso; XXXV Jornadas Científicas Anuales-Asociación de biología de Tucuman; 2018

Asociación de Biología de Tucuman

Environmental phosphate (Pi) modulates in different bacteria the levels of intracellular polyphosphate (polyP), a molecule that plays important roles in microbial metabolism. Herbaspirillum seropedicae is a diazotrophic and endophytic bacterium associated with important agricultural crops, promoting plant growth and increasing productivity. Physiological response to prevailing levels of nutrients such as Pi is scarce. The aim of this work was to evaluate the molecular changes in H. seropedicae due to different intracellular polyP levels modified by the Pi media concentrations. Results show that H. seropedicae SmR1 cultures grown in high Pi (50 mM) medium maintained high polyP levels in stationary phase, while cells grown in sufficient Pi (5 mM) medium degraded it. By a RNA-seq approach, comparison of RNA profiles between high and low polyP conditions revealed that 620 genes were differentially expressed, being 53% repressed and 43% induced in high-polyP condition. In this condition, the genes responsible for energy production process, two component regulatory systems, amino acid transport and metabolism, chemotaxis and inorganic ion transport and metabolism and cellular homeostasis were up-regulated. Gene expression related with adhesion capacity, chemotaxis and motility, PBH production and colonization were phenotypically corroborated. Present findings provide, for the first time, a global picture of the cellular responses to environmental Pi concentration and give insights about signals triggered by intracellular polyP that could be critical for H. seropedicae fitness and applications