EVALUATION OF mRNA AND THERMAL STRESS IN UNFERTILIZED EGGS OF RED CUSK-EEL Genypterus chilensis

The red cusk-eel (Genypterus chilensis) is a native species with high potential to Chilean aquaculture diversification. For a successful establishment of a new aquaculture industry, understand the biology of the gametes and how environmental factors such as temperature affect them is key. In the unfertilized egg, maternal mRNAs play a key role in early embryonic development until activation of zygotic transcription. The objective of this work was to evaluate the effect of high temperature (HT) and low temperature (LT) stress and their relation with maternal mRNA in unfertilized eggs of G. chilensis.

The eggs of G. chilensis were collected from CIMARQ and separated in control (19°C), HT stress group (26°C) and LT stress group (7°C). The groups were maintained for 6 hours (T6) to their respective temperature treatment. In each experimental group, 5 pools (30~ eggs each) were collected for RNA and DNA purification.

Low and high temperature produces a significant change in AP sites (Fig. 1A), evidencing the DNA damage generated by this type of stressor, with a higher effect in the LT stress group. Respect to the mRNA levels, significant differences were observed for ddit4, gpx1, hsp60, and igf-1 (Fig 1B to 1E), with no significant differences in the expression of npm2 (Fig 1F). The changes observed in mRNA levels could be related to the activation/degradation of maternal dormant transcripts by thermal stress. This effect of thermal stress could affect the quality and developmental competence of the eggs, information that could be considered for a successful establishment of G. chilensis industry. Funding: CONICYT FONDECYT Postdoctorado 3180283.