Fig. 6

Asc-C9 acts as a cold signal to promote beetle’s cold acclimation. a The effect of asc-C9 on the supercooling points (SCPs) of the larval beetles (n = 20). b Probit regression between mortality rate and temperature of asc-C9-fed and control beetles (n = 10 for each treatment). c Distribution of Gene Ontology (GO) terms with > 1% of annotated genes in the category of biological process enriched from the DETs between asc-C9-fed and control beetles. d Simplified schematic diagram of the synthesis and metabolism of these three cryoprotectants modified from Barth et al. [33]. The genes in red are significantly upregulated and those in blue are significantly downregulated, and those in black have no changes in expression after treatment of asc-C9. Genes legends: Tpp, trehalose-phosphate phosphatase; Gp, glycogen phosphorylase; A1e, aldose-1-epimerase; Akr, aldo-keto reductase; Gpi, glucose-6-phosphate isomerase; Pfk, 6-phospho-fructokinase; Suc, succinyl-CoA ligase; Eno, enolase; Idh, isocitrate dehydrogenase; FBPase, fructose-1,6-bisphosphatase; Pgm, phosphoglycerate mutase. G1P, glucose-1-phosphate; GAP, glyceraldehyde-3-phosphate. The data were shown as mean ± s.e.m. Two-tailed Student’s t test was used to test significant differences. *P < 0.05; **P < 0.01; ***P < 0.001. C9, asc-C9-fed beetles (4 °C); Control beetles (25 °C). The last larval beetles in a and b were collected at 6–8 Oct. 2018 and 20–25 Oct. 2019, respectively