Hexose-1P partitioning in Rhodococcus: a comparative analysis between two different rhodococcal species

ASENCION DIEZ, MATÍAS D.; CEREIJO, ANTONELA E.; IGLESIAS, ALBERTO A. ; ALVAREZ, HÉCTOR M.

Paraná, Entre Rios

Congreso; LIV Reunión Anual de la Sociedad Argentina de Investigaciones en Bioquímica y Biología Molecular; 2018

The study of enzymes related to carbon partitioning between different storage compounds is critical for a better understanding of the physiology and metabolism of biotechnological microorganisms. The oleaginous Rhodococcus jostii and the phytopathogenic R. fascians are two actinobacteria capable of accumulate lipids and glycogen with differential metabolic features. Then, we comparatively analyzed the growth of both rhodococcal species in different carbon sources and the production of glycogen and TAGs. Results show different behavior regarding carbon source utilization between both species: while R. fascians reach the stationary phase in hours, R. jostii take almost 12 days when both are grown in glycerol; and the opposite occurs when growth on glucose. Furthermore, glycogen accumulation significantly differs depending on the carbon source, nitrogen availability and growth phase. The expression analysis of two key enzymes involved in hexose-1P partition, ADP-glucose pyrophosphorylase and UDP-glucose pyrophosphorylase, in the different culture conditions showed a differential expression pattern for the latter whilst ADP-Glc PPase remained constant. Then, UDP-Glc PPase could be subjected to protein turn-over regulatory mechanisms while the activity of ADP-Glc PPase (and consequently glycogen accumulation) is allosterically regulated, according to dynamic metabolic scenarios. In this regard, our results reinforce the importance of deepen the study of the carbon metabolism to identify the major physiologic differences between these rhodococcal species for future metabolic engineer and biotechnological applications