Role of protein PQQ in phosphate solubilizing ability and levels of pqqE gene expression in the native peanut bacterium Serratia sp S119

LUDUEÑA, L.,; FABRA, A.; TAURIAN, T

Avances en estudios básicos y aplicados sobre PGPR en Latinoamérica

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Año: 2014; p. 1 - 136

The mineral phosphate solubilization (MSP) phenotype observed in some microorganisms is attributed predominantly to the secretion of organic acids such as gluconic and 2-cetogluconic acid. Glucose dehydrogenase (GDH) enzyme catalyzes the oxidation of glucose to gluconic acid and requires pyrroloquinoline quinone protein (PQQ) for its activity. This study analyses the role of PQQ protein on the mineral phosphate solubilizing activity of Serratia sp S119 and the expression of pqqE gene under P-limiting conditions. A PQQ mutant, Serratia sp RSLpqqE-, deficient in its phosphate solubilizing ability was obtained. Complementation of mutant´s phenotype was performed by adding synthetic PQQ to the bacterium growth medium. To evaluate pqqE gene expression in bacterium growing under phosphate starvation or soluble P supplemented conditions, RT PCR qualitative analysis and quantitative real-time PCR were performed. The 16s rDNA and rpoB gene were used as housekeeping genes and pqqE gene as the target one. The results suggest that PQQ protein is involved in the phosphate solubilizing ability of Serratia sp S119 and that pqqE gene expression seems to be constitutive in this bacterium. KEY WORDS: Phosphate solubilization, pyrroloquinoline quinone (PQQ), pqqE gene, Serratia sp