Arachis hypogaea PGPR FROM ARGENTINE SOIL MODIFIES ITS LIPIDS COMPONENTS IN RESPONSE TO TEMPERATURE

REGUERA Y; CESARI A; KILMURRAY C; PAULUCCI N; DARDANELLI M

Mar del Plata

Congreso; . LI Annual Meeting of the Argentine Society for Biochemistry and Molecular Biology Research.; 2015

A Gram-negative, aerobic, motile by subpolar flagella, rod shaped bacterium was isolated from Arachis hypogaearhizosphera from a Río Cuarto soil. L115 strain was identified as Ochrobactrum intermedium (16S rRNA geneanalysis). Mechanism related to plant growth promotion were analyzed. L115 synthesize siderophores (ChromeAzurol S agar), produce indol acetic acid (Salkowski colorimetric method) and presented 1-aminocyclopropane-1-carboxylic acid (ACC) deaminase activity (medium supplemented with ACC). L115 increased the peanut shootlength and root dry weight (plant growth chamber inoculation test) indicating a PGPR role. Considering that thepeanut seeding temperature range of soil varies from 16-18°C, we evaluated the effects of 18°C on bacterial growthin respect to 28°C. A decrease in viability was observed, although L115 was able to adapt. To understand themechanisms of adaptation, after 24 h of incubation in medium YEM, total fatty acids (FA) were extracted andanalyzed by GC. Phospholipids (PL) were separated by TLC after incorporating [1-14C] sodium acetate to culture. At18°C, it was observed an increase of 18:1Δ11 FA and a decrease of 16:0 and 18:0 FA. The most important change inPL was an increase in phosphatidylcholine and a decrease in phosphatidylethanolamine. The results suggest thatL115 adapt to low grown temperature by modifying FA and PL membrane composition.