CONICET | Buscador de Institutos y Recursos Humanos

riatoma infestans present rhythms in diverse biological processes. Previous studies in the expression of three cytochromes P450 genes and the NADPH cytochrome P450 reductase (CPR) gene revealed that P450 genes would be involved in the development of resistance to insecticides in T. infestans. To investigate the presence of rhythms in the expression of genes related to insecticide resistance, we explored the daily expression at mRNA level of CPR gene and a P450 gene (CYP4EM7) in fat body of groups of T. infestans maintained under light/dark cycle (LD), constant light (LL), and constant dark (DD). In LD, the CPR gene expression profile of females showed two peaks, conserved in DD and lost in LL, that suggest the CPR expression is under endogenous clock regulation. In contrast, in males was not observed a rhythmic profile in the expression of the CPR gene. In LD, the expression of CYP4EM7 gene showed daily significant variations. Females presented a peak at dawn and males showed two peaks, one at dawn and other at sunset. On the other hand, to better understand the molecular bases of the biological clock, we analysed the expression at mRNA level of the clock genes period (per) and timeless (tim) in LD, LL, and DD conditions. The per and tim genes expression in nervous tissue of adults T. infestans varies with a daily rhythm in LD, showing a significant peak at sunset. These rhythms agrees with those described in Drosophila melanogaster and would promote a peak of PER and TIM protein levels at night. As expected, in LL no daily increase was detected in per and tim transcript levels. Besides, the presence of per transcript in different tissues of adult individuals and in nervous tissue of nymphs evidenced activity of peripheral clocks in adults and activity of the central clock in nymphs of T. infestans. Further studies will help to clarify the relationship between the endogenous clock and the expression of genes involved in the insecticide metabolisms.