AUTHOR=Lu Ming-Xing , Pan Dan-Dan , Xu Jing , Liu Yang , Wang Gui-Rong , Du Yu-Zhou 

TITLE=Identification and Functional Analysis of the First Aquaporin from Striped Stem Borer, Chilo suppressalis

JOURNAL=Frontiers in Physiology

VOLUME=9

YEAR=2018

URL=https://www.frontiersin.org/journals/physiology/articles/10.3389/fphys.2018.00057

DOI=10.3389/fphys.2018.00057

ISSN=1664-042X

ABSTRACT=<p>Aquaporins are integral membrane proteins some of which form high capacity water-selective channels, promoting water permeation across cell membranes. In this study, we isolated the aquaporin transcript (<italic>Cs</italic>Drip1) of <italic>Chilo suppressalis</italic>, one of the important rice pests. <italic>Cs</italic>Drip1 included two variants, <italic>Cs</italic>Drip1_v1 and <italic>Cs</italic>Drip1_v2. Although <italic>Cs</italic>Drip1_v2 sequence (&gt;409 bp) was longer than <italic>Cs</italic>Drip1_v1, they possessed the same open reading frame (ORF). Protein structure and topology of <italic>Cs</italic>Drip1 was analyzed using a predicted model, and the results demonstrated the conserved properties of insect water-specific aquaporins, including 6 transmembrane domains, 2 NPA motifs, ar/R constriction region (Phe<sup>69</sup>, His<sup>194</sup>, Ser<sup>203</sup>, and Arg<sup>209</sup>) and the C-terminal peptide sequence ending in “SYDF.” Our data revealed that the <italic>Xenopus</italic> oocytes expressing <italic>Cs</italic>Drip1 indicated <italic>Cs</italic>Drip1 could transport water instead of glycerol, trehalose and urea. Further, the transcript of <italic>Cs</italic>Drip1 expressed ubiquitously but differentially in different tissues or organs and developmental stages of <italic>C. suppressalis. Cs</italic>Drip1 mRNA exhibited the highest level of expression within hindgut and the third instar larvae. Regardless of pupae and adults, there were significantly different expression levels of <italic>Cs</italic>Drip1 gene between male and female. Different from at low temperature, the transcript of <italic>Cs</italic>Drip1 in larvae exposed to high temperature was increased significantly. Moreover, the mRNA levels of <italic>Cs</italic>Drip1 in the third instar larvae, the fifth instar larvae, pupae (male and female), and adults (male and female) under different humidities were investigated. However, the mRNA levels of <italic>Cs</italic>Drip1 of only female and male adults were changed remarkably. In conclusions, <italic>Cs</italic>Drip1 plays important roles in maintaining water homeostasis in this important rice pest.</p>