GLUT2 gene from Penaeus monodon: Molecular characterization, expression and association with tolerance to low salinity stress

The full-length cDNA sequence of Penaeus monodon glucose transporter-2 (PmGLUT2) was cloned in this study using the RACE method. Quantitative real-time PCR was used to analyze the differential expression of PmGLUT2 during the development of P. monodon larvae in different tissues and under low salinity stress. The PmGLUT2 cDNA exhibited a total length of 2018 base pairs, with 94 base pairs located in the 5' untranslated region (UTR) and 352 base pairs in the 3' UTR. Additionally, the sequence contained 29 base poly (A) tails and 1572 base pairs within the open reading frame (ORF), capable of encoding 523 amino acids. Through a comparative analysis of the amino acid sequences of PmGLUT2 and LvGLUT2, it was determined that PmGLUT2 had 94.77% homology with Tret1 gene of Litopenaeus vannamei, and 60.54% homology with GLUT2 gene of L. vannamei. The results indicated that there was a fluctuation in PmGLUT2 expression levels from zygote to postlarva development, with initial reduction followed by an increase, although the difference was not statistically significant. According to the molting analysis, the highest expression level of PmGLUT2 was observed in the hepatopancreas during the premolt period, while the gill and gut exhibited peak expression levels during the intermolt period. PmGLUT2 was found to be most abundant in lymph tissue, followed by gill tissue, and least abundant in ootheca, according to the tissue expression analyses. Following 96 hours of acute salt stress, there was a notable inhibition in the expression of PmGLUT2 in the hepatopancreas and gills. Additionally, the expression level in the gills at 96 hours was significantly lower compared to the baseline level at 0 hours.