Identification of ecdysteroidogenic enzyme genes and their expression during pupal diapause in the cabbage armyworm, Mamestra brassicae

Abstract

In this study, we identified ecdysteroidogenic enzymes in the cabbage armyworm, Mamestra brassicae, and demonstrated reduced expression of these genes during diapause. Some insects employ a temporary developmental arrest, diapause, to survive in severe environments. The titres of the moulting hormone ecdysteroid were reduced in diapause pupae of M. brassicae; therefore, ecdysteroidogenesis might be suppressed by a diapause-specific mechanism. To clarify expression changes of ecdysteroidogenic enzyme genes during diapause in M. brassicae, we first identified the genes for seven ecdysteroidogenic enzymes: Neverland, Non-molting glossy (Nm-g), CYP307A1 (Spook), CYP306A1 (Phantom), CYP302A1 (Disembodied), CYP315A1 (Shadow) and CYP314A1 (Shade). Enzymatic assays using heterologous expression in Drosophila Schneider 2 (S2) cells and analysis of mRNA distribution indicated that the identified genes were ecdysteroidogenic enzymes of M. brassicae. Expression levels of these ecdysteroidogenic enzyme genes were compared between prothoracic glands in different pupal stages throughout diapause. Immediately after pupation, diapause-destined pupae showed similar expression levels of ecdysteroidogenic enzyme genes to those of nondiapause pupae. All of these genes showed reduced gene expression after diapause initiation. Expression was immediately increased in diapause-destined pupae at the postdiapause quiescence phase. These results indicate that reduced expression of ecdysteroidogenic enzyme genes suppresses ecdysteroidogenesis and maintains developmental arrest during diapause.

Identification and expression analysis of cytochrome P450 genes in Plecoptera oculata (Lepidoptera: Noctuidae)

“…Furthermore, CYP18A1 was tandemly repeated alongside CYP306A1 , which is one of the “Halloween genes” involved in the synthesis of ecdysone (Feyereisen ), and both PoCYP306A1 and PoCYP18A1 were highly expressed in the fat body. Shade ( PoCYP314A1 ), another Halloween gene that was identified in the present study, was also highly expressed in the fat body, consistent with the results of previous studies in Mamestra brassicae (Ogihara et al ) and Drosophila melanogaster larvae (Petryk et al ). The expression of Shade was down‐regulated by exposure to lambda‐cyhalothrin.…”

Quantitative transcriptomic and proteomic analyses reveal the potential maintenance mechanism of female adult reproductive diapause in Chrysoperla nipponensis

“…Knockdown of ECR in non‐diapause female adults had a reproductive defect, and juvenile hormone analog (JHA) application can rescue this defect 57 . Consistent with our results, lower expression of Phm was observed during diapause in Colaphellus bowringi , Chymomyza costata , and Mamestra brassicae 57–59 . These results indicated that a short photoperiod might induce reproductive diapause in C. nipponensis by altering the expression of genes in the JH and 20E signaling pathways.…”

Changes in expressions of ecdysteroidogenic enzyme and ecdysteroid signaling genes in relation to Bombyx embryonic development

“…These results clearly indicated that the observed differential changes in gene expression levels were indeed related to the embryonic diapause process, and are thus potentially involved in the diapause process. Previous study showed that in Mamestra brassicae , reduced expressions of ecdysteroidogenic enzyme genes suppress ecdysteroidogenesis and maintain developmental arrest during pupal diapause (Ogihara et al, 2017). Our present study provides useful insights into upstream and downstream regulation of ecdysteroid signaling during the embryonic diapause process.…”