pqqE gene as a molecular marker of phosphate solubilizing bacteria associated to peanut plant

ANZUAY MARIA SOLEDAD; CHIATTI, MARIO; LILIANA MERCEDES LUDUEÑA; DALMASSO, ROMINA; FERNÁNDEZ VALDÉS, PILAR; - ANGELINI, JORGE,; TANIA TAURIAN

Congreso; XVII Congreso Argentino de Microbiología General; 2022

In Argentinian peanut agricultural area, low values of soil phosphorus (P) were detected. Within soilbacteria, some are capable of exercise beneficial effects for plants growth, for example thesolubilization of insoluble phosphates that providing P to plants. This nutrient can be released frominorganic phosphorous compounds by the synthesis of organic acids such as gluconic acid (GA). The production of GA is the main mechanism by which Gram-negative bacteria solubilize insolubleinorganic soil P sources. This organic acid is produced by phosphate solubilizing bacteria (PBS) by the action of glucose dehydrogenase (GDH)-PQQ holoenzyme. The role of PQQ cofactor in this oxidative pathway is essential. Previous results from our laboratory indicated that a large number of Gramnegative PSB contain in their genome the pqqE gene, one of the essential genes involved in PQQ biosynthesis. Besides, the presence of this gene was detected in PSB from mixed samples of bacterial cultures. The objective of this study was to analyze the presence of pqqE gene in rhizospheric soil samples in presence and absence of peanut plants and inoculated or not with PSB. DNA was isolated from samples of rhizospheric soil associated to fields of peanut plants from Río Cuarto (SRRC), San Severo (SRSS), La Carlota (SRLC), Reducción (SRR), Gigena (SRG), San Ambrosio (SRSA). Also, rhizospheric soil samples obtained from a microcosms assay with peanut plants growing in SRRC inoculated (SRPI) or not (SRPNI) with SS-ER-24 strain were analyzed. SRRC without plants and inoculated with SS-ER-24 strain (SRI) and non-rhizospheric soil were also analyzed (SNR). PCRs-pqqE were performed using two pairs of primers designed in our laboratory. The pair pqqEF-317/1019 that amplify pqqE gene from several bacteria of different genera and the specific pair pqqEPS1/pqqEPS2