Trehalose‐6‐phosphate phosphatases are involved in trehalose synthesis and metamorphosis in Bactrocera minax

Abstract

Trehalose is the principal sugar circulating in the hemolymph of insects, and trehalose synthesis is catalyzed by trehalose-6-phosphate synthase (TPS) and trehalose-6-phosphate phosphatase (TPP). Insect TPS is a fused enzyme containing both TPS domain and TPP domain. Thus, many insects do not possess TPP genes as TPSs have replaced the function of TPPs. However, TPPs are widely distributed across the dipteran insects, while the roles they play remain largely unknown. In this study, 3 TPP genes from notorious dipteran pest Bactrocera minax (BmiTPPB, BmiTPPC1, and BmiTPPC2) were identified and characterized. The different temporal-spatial expression patterns of 3 BmiTPPs implied that they exert different functions in B. minax. Recombinant BmiTPPs were heterologously expressed in yeast cells, and all purified proteins exhibited enzymatic activities, despite the remarkable disparity in performance between BmiTPPB and BmiTPPCs. RNA interference revealed that all BmiTPPs were successfully downregulated after double-stranded RNA injection, leading to decreased trehalose content and increased glucose content. Also, suppression of BmiTPPs significantly affected expression of downstream genes and increased the mortality and malformation rate. Collectively, these results indicated that all 3 BmiTPPs in B. minax are involved in trehalose synthesis and metamorphosis. Thus, these genes could be evaluated as insecticidal targets for managing B. minax, and even for other dipteran pests.

Validamycin Inhibits the Synthesis and Metabolism of Trehalose and Chitin in the Oriental Fruit Fly, Bactrocera dorsalis (Hendel)

“…Nevertheless, its inhibitory effect on trehalose formation is possibly overwhelmed by the inhibitory effect on trehalose hydrolysis, leading to trehalose accumulation in validamycin-injected insects ( Figure 1 ). Noteworthy, a lot of insect species lack TPPs, in that TPSs have incorporated an active TPP domain over a long history of evolution to become fuse proteins and function as both TPS and TPP [ 61 ]. However, dipteran insects, especially tephritidae species, possess abundant independent active TPPs [ 61 ].…”

“…Noteworthy, a lot of insect species lack TPPs, in that TPSs have incorporated an active TPP domain over a long history of evolution to become fuse proteins and function as both TPS and TPP [ 61 ]. However, dipteran insects, especially tephritidae species, possess abundant independent active TPPs [ 61 ]. We suppose that the other TPPs of B. dorsalis can also be affected by validamycin.…”

Trehalose-6-Phosphate Synthase Contributes to Rapid Cold Hardening in the Invasive Insect Lissorhoptrus oryzophilus (Coleoptera: Curculionidae) by Regulating Trehalose Metabolism

“…TPS genes have been identified from different insect species [19][20][21][22][23][24]. However, TPP genes have only been found in certain insect species, predominantly in dipteran insects [25][26][27]. Three categories of TPS genes (TPS1, TPS2, and TPS3) have been discovered in insects to date [28,29].…”