Involvement of a putative allatostatin in regulation of juvenile hormone titer and the larval development in Leptinotarsa decemlineata (Say)

• Published in: Gene Vol. 554; no. 1; pp. 105 - 113
• Main Authors: Meng, Qing-Wei, Liu, Xin-Ping, Lü, Feng-Gong, Fu, Kai-Yun, Guo, Wen-Chao, Li, Guo-Qing
• Format: Journal Article
• Language: English
• Published: Netherlands Elsevier B.V 01.01.2015
• Subjects: Allatostatin gene; Amino Acid Sequence; Animals; Cloning, Molecular; Coleoptera - growth & development; Development; Expressed Sequence Tags; Gene Expression Profiling; Gene Expression Regulation, Developmental; Growth; Hemolymph - metabolism; Juvenile hormone titer; Juvenile Hormones - metabolism; Larva - growth & development; Leptinotarsa decemlineata; Molecular Sequence Data; Neuropeptides - physiology; Phylogeny; RNA interference; RNA, Double-Stranded - metabolism; RNA, Messenger - metabolism; Sequence Homology, Amino Acid; Solanum tuberosum; dsRNA; RNAi; RNA interference; Growth; LC–MS; AS; ANOVA; Leptinotarsa decemlineata; Development; Allatostatin gene; CYP; JH; JHAMT; Juvenile hormone titer
• ISSN: 0378-1119; 1879-0038
• DOI: 10.1016/j.gene.2014.10.033

Juvenile hormone III (JH III) plays primary roles in regulation of metamorphosis, reproduction and diapause in Leptinotarsa decemlineata, a notorious defoliator of potato. The neurosecretory cell-borne substance(s) negatively affects the final two steps in JH biosynthesis, catalyzed respectively by an epoxidase CYP15A1 and a juvenile hormone acid methyltransferase (JHAMT). In a few insect species other than L. decemlineata, the inhibitory substance is allatostatin (AS) neuropeptide. In this study, two putative AS genes encoding LdAS-C and LdAS-B precursors were cloned. Both LdAS-C and LdAS-B were expressed in the egg, larvae, pupae and adults, and highly expressed in the brain and the gut. Dietary introduction of double-stranded RNAs (dsRNAs) targeting LdAS-C and LdAS-B successfully knocked down respective target genes. Ingestion during 3 and 6 consecutive days of dsLdAS-C significantly increased the LdJHAMT mRNA levels by 3.8 and 9.9 fold respectively. In contrast, ingestion of dsLdAS-B only slightly increased the LdJHAMT expression level by 1.1 and 1.7 fold. Moreover, after one, two and three days' ingestion of dsLdAS-C, the relative JH levels in the hemolymph of treated larvae were 2.5, 4.2 and 1.9 fold higher than those in control beetles. Furthermore, ingestion of dsLdAS-C and dsLdAS-B significantly affected larval growth and delayed larval development. Thus, we provide a line of experimental evidence in L. decemlineata to support the concept that AS-C acts as an allatostatin and inhibit JH biosynthesis. [Display omitted] •LdAS-C and LdAS-B were highly expressed in the head and the gut.•Ingestion of dsLdAS-C significantly increased the LdJHAMT mRNA level.•LdAS-C knockdown significantly increased hemolymph JH level.•Knockdown LdAS-C and LdAS-B affected larval development.