اثر القای دیاپوز بر میزان قندها و پلی ال ها و بیان ژن های مرتبط با دیاپوز در کرم خوشه خوار انگور Lobesia botrana (Lepidoptera: Tortricidae)

The European grapevine moth, Lobesia botrana (Denis and Schiffermueller) (Lepidoptera: Tortricidae), damage to grapes is of significant economic importance in the country. In spring, the young larvae feed on the flowering buds and cover them with webs; as a result, they cause the flowers and buds to dry up and fall off. Larvae of the second-generation feed on unripe grapes and larvae of the third-generation feed on ripe grapes. The aim of this study was to investigate the induction of diapause and its effects on sugar and polyol content, as well as the expression of several genes related to diapause. The larvae were reared on an artificial diet under non-diapause conditions for six generations, maintaining a constant temperature of 23 ± 0.5 ºC, relative humidity of 75%, and a light-dark cycle of 16:8 h (L:D). Subsequently, one-day-old eggs were exposed to a photoperiod of 12:12 h (L:D) under the same temperature and humidity conditions to induce diapause. The experiment was conducted in 3 replications and each replication included five pupae. Six compounds, trehalose, glucose, myo-inositol, iso-erythritol, mannitol, and glycerol, were identified in the whole-body extract of L. botrana pupae reared in the laboratory in both diapause and non-diapause states. The results showed that the increase in glucose, glycerol, trehalose, and myo-inositol in the diapause treatment was significant compared to that in the non-diapause treatment. Furthermore, glucose, glycerol, and trehalose were present in higher quantities in diapausing pupae, exhibiting 3.8-fold, 2.3-fold, and 2.1-fold increases, respectively, compared to non-diapausing pupae. The expression levels of six genes, including heat shock protein 70 (HSP70), heat shock protein 90 (HSP90), trehalose phosphate synthase (TPS), glycerol kinase (GK), glycerol-3-phosphate dehydrogenase (GPDH), and DNA methyltransferase 1 (DNMT1), were significantly higher in diapausing pupae. These findings suggest that diapause in this insect is primarily regulated by the expression of diapause-associated genes and the accumulation of essential reserves during the cold season.