Molecular characterization of a ryanodine receptor gene from Spodoptera exigua and its upregulation by chlorantraniliprole

• The full-length RyR cDNA from Spodoptera exigua (SeRyR) was cloned and characterized.
• Chlorantraniliprole can up-regulate the Se RyR expression.
• SeRyR expression was correlated with the log concentration of chlorantraniliprole.

Chlorantraniliprole is a novel diamide insecticide that targets the insect ryanodine receptor, a Ca2+ release channel. Spodoptera exigua is a significant insect pest, and chlorantraniliprole is the most popular diamide insecticide used against this pest. To better understand the effects of diamides on RyR expression and [Ca2+], we isolated the SeRyR cDNA and investigated changes in SeRyR expression as a result of the application of chlorantraniliprole. The full-length cDNAs of SeRyR contain an open reading frame (ORF) of 15,357 bp with a predicted protein consisting of 5118 amino acids. SeRyR shares 77–92% identity with other insect RyR isoforms and 45–47% identity with vertebrate RyR isoforms. Furthermore, the relative expression abundances of RyR mRNA extracted from S. exigua fat body cells after 24 h of culture in 0.1, 1, 10, 100 nM, 1 µM and 100 µM of chlorantraniliprole changed 1.04-, 0.89-, 1.83-, 2.58-, 4.03- and 3.12-fold compared to blank control, respectively. The regression equation for the relative expression levels of SeRyR after 24 h as a function of the chlorantraniliprole concentration was Y = 0.6455 + 0.8188LgX, R2 = 0.97093 for the cell line IOZCAS-Spex-II. These results outline the effects of chlorantraniliprole on the expression of SeRyR and provide a basis for the discovery of a compound that may exhibit selective insect activity.

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