Characteristics of Halloween genes and RNA interference‐mediated functional analysis of LmCYP307a2 in Locusta migratoria

Abstract

Halloween genes are involved in the biosynthesis of the molting hormone, which plays a key role in insect ecdysis, development, metamorphosis, and reproduction. Our previous work identified five Halloween genes from Locusta migratoria, but their functions are currently unknown. In this study, the sequences of these five Halloween genes were analyzed and characterized. LmCYP307a2, LmCYP306a1, LmCYP302a1, and LmCYP315a1 were primarily expressed in the prothoracic glands, while LmCYP314a1 was universally expressed in peripheral tissues, especially in the ovaries and Malpighian tubules. All five Halloween genes were mainly expressed from the 5th to the 7th d in 5th-instar nymphs. RNA interference (RNAi) silencing of LmCYP307a2 resulted in severe molting delays and molting failure, which could be rescued by supplementary 20hydroxyecdysone. A hematoxylin and eosin staining analysis suggested that the RNAi of LmCYP307a2 inhibited the ecdysis process by inhibiting the apolysis and degradation of the old cuticle, and by promoting the synthesis of a new cuticle. Quantitative reverse transcription polymerase chain reaction results showed that the expressions of LmE74, LmCht5, and LmCht10 were dramatically down-regulated, while that of LmChsI was substantially up-regulated, after knockdown of LmCYP307a2. The results suggest that LmCYP307a2 is related to the molt process via regulation of chitin synthesis and degradation.

RNAi-Mediated Silencing of Putative Halloween Gene Phantom Affects the Performance of Rice Striped Stem Borer, Chilo suppressalis

“…RNAi knockdown significantly downregulated the relative transcript level in the ds C s -Phm -injected group which led to a significantly reduced ecdysteroid titer. Similar findings have also been reported of reduced ecdysteroid titers with the loss of Halloween enzymes [ 17 , 18 , 24 , 35 , 36 , 37 , 49 , 50 ]. We also noted that negative effects in immature stages, such as mortality and delayed larval development, were observed in ds Cs-Phm -injected insects because of the reduced ecdysteroid titer.…”

“…In this report, we demonstrated the characterization and the relative transcript levels of Halloween gene Cs-Phm in the rice striped stem borer, C. suppressalis . It has been identified in several insects species that Halloween genes are involved in ecdysteroidogenesis [ 8 , 19 , 24 , 42 ]. Helix-C, Helix-I, Helix-K, PERF motif, and heme-binding domain are well-conserved typical cytochrome P450 motifs [ 43 ].…”

“…In contrast, two additional paralogs exist for spook , spookier (CYP307a2), and spookiest (CYP307B1) [ 23 ]. Mutant embryos of the Halloween genes show a similar phenotype characterized by low ecdysteroid titers, dorsal closure, failure of head involution, hindgut abnormality, failure to induce ecdysteroid receptor genes, and lethality [ 18 , 19 , 24 ].…”

Effects of transgenic cotton lines expressing dsAgCYP6CY3‐P1 on the growth and detoxification ability of Aphis gossypii glover

“…Successful RNAi-mediated pest management depends not only on effective target gene screening, but also on effective and feasible dsRNA delivery methods. 18,42 dsRNA delivery methods for RNAi in insects mainly include injection, 43 feeding, 44 spraying 18,30 and/or transgenic plants. 19 Injection delivers an exact amount of dsRNA to target tissues, which is obviously impossible to apply to crop protection in the field.…”

Lethal giant larvae gene is required for normal nymphal development and midgut morphogenesis in Locusta migratoria

“…Locusta migratoria (Orthoptera: Acrididae) is an important agricultural insect pest worldwide, as well as a good model organism for the study of insect physiology and behavior (Zhang et al ., 2021). In this study, we identified a single Lgl gene from a transcriptome sequencing project in L. migratoria (Zhang et al ., 2018) and characterized its expression patterns in selected developmental stages and tissue types.…”