RNA-SEQ TRANSCRIPTIONAL PROFILING OF Herbaspirillum seropedicae IN RESPONSE TO SUFFICIENT AND HIGH PHOSPHATE CONCENTRATION

GRILLO PUERTAS, MARIANA; PANKIEVICZ, VANIA CARLA; TADRA-SFEIR, MICHELLE ; PEDRAZA, RAÚL O; RAPISARDA, VIVIANA ANDREA; SOUZA, EMANUEL MALTEMPI

Buenos Aires

Congreso; Reunión conjunta de sociedades de biociencias; 2017

SAIB

Herbaspirillum seropedicae is a diazotrophic and endophyticbacterium associated with important agricultural crops, promotingplant growth and increasing productivity. Its agricultural use requiresstudies on its physiological response to prevailing levels ofnutrients such as phosphate (Pi). It has been previously reportedin different bacteria that environmental Pi modulates the levels ofintracellular polyphosphate (polyP), a molecule that plays importantroles in microbial metabolism. The aim of this work was to evaluatethe intracellular polyP levels and the differentially expressedgenes in H. seropedicae grown in sufficient or high Pi conditions. H.seropedicae SmR1 was grown in NFbHN-malate medium modifiedwith 5 or 50 mM Pi; culture absorbance at 600nm and polyP levelswere measured at different times during 24 h. Results showedthat cultures grown in high Pi medium reached higher cell densitiesthan cultures grown in sufficient Pi media and maintained high polyPlevels in stationary phase. To analyze if these differences in polyP levels could generate changes in gene expression, mRNA fromcell grown in different media was purified and used for RNA-seqprofiling. Comparison of RNA profile between sufficient and high Piconditions revealed that 620 genes were differentially expressed,being 53 and 43% repressed and induced by high Pi, respectively.Most of the induced genes in the high Pi condition were involvedin energy production process, two component regulatory systems,amino acid transport and metabolism, chemotaxis and inorganic iontransport and metabolism. The ability to respond to environmentalsignals which modulates polyP production could be critical in diverseaspects of H. seropedicae.