Effects of P limitation and molecules from peanut root exudates on pqqE gene expression and pqq promoter activity in the phosphate-solubilizing Q6 strain Serratia sp. S119

LILIANA LUDUEÑA; MARÍA SOLEDAD ANZUAY; MAGALLANES-NOGUERA, CYNTHIA; M. LAURA TONELLI; IBÁÑEZ FERNANDO; ANGELINI JORGE; ADRIANA FABRA; MATTHEW MCINTOSH; TANIA TAURIAN

RESEARCH IN MICROBIOLOGY

ELSEVIER SCIENCE BV

Lugar: Amsterdam; Año: 2017

0923-2508

The mineral phosphate-solubilizing phenotype in bacteria is attributed predominantly to secretion of gluconic acid produced by oxidation ofglucose by the glucose dehydrogenase enzyme and its cofactor, pyrroloquinoline quinone. This study analyzes pqqE gene expression and pqqpromoter activity in the native phosphate-solubilizing bacterium Serratia sp S119 growing under P-limitation, and in the presence of rootexudates obtained from peanut plants, also growing under P-limitation. Results indicated that Serratia sp. S119 contains a pqq operon composedof six genes ( pqqA,B,C,D,E,F) and two promoters, one upstream of pqqA and other between pqqA and pqqB. PqqE gene expression and pqqpromoter activity increased under P-limiting growth conditions and not under N-deficient conditions. In the plantebacteria interaction assay, theactivity of the bacterial pqq promoter region varied depending on the concentration and type of root exudates and on the bacterial growth phase.Root exudates from peanut plants growing under P-available and P-limiting conditions showed differences in their composition. It is concludedfrom this study that the response of Serratia sp. S119 to phosphorus limitation involves an increase in expression of pqq genes, and thatmolecules exuded by peanut roots modify expression of these phosphate-solubilizing bacterial genes during plantebacteria interactions.© 2017 Institut Pasteur. Published by Elsevier Masson SAS. All rights reserved.