RNA interference‐mediated knockdown of the transcription factor Krüppel homologue 1 suppresses vitellogenesis in Chilo suppressalis

Abstract

Vitellogenesis in holometabolous insects involves the production and secretion of vitellogenin (Vg) and other yolk protein precursors in developing oocyte by the fat body, all of which is predominantly orchestrated by juvenile hormone (JH). Krüppel homologue 1 (Kr‐h1) is a zinc finger transcription factor that has been demonstrated to be a JH‐early inducible gene and to contribute to reproduction. However, the exact molecular function of Kr‐h1 in insect reproduction is poorly understood. In the current study, we used the notorious pest Chilo suppressalis as a model system to investigate the role of Kr‐h1 in female reproduction. Cloning and sequencing C. suppressalis Kr‐h1 revealed that it shares high identity with its homologues from other lepidopteran insects. Moreover, RNA interference‐mediated knockdown of CsKr‐h1 substantially reduced the transcription of Vg in the fat body, dramatically decreased yolk protein deposition and also impaired oocyte maturation and ovarian development, indicating that Kr‐h1 is indispensable for normal vitellogenesis in C. suppressalis. Based on these results, we conclude that Kr‐h1 is crucial to reproduction in insects and that targeting this gene could potentially be a new way to suppress rice pests.

Regulatory Mechanisms of Vitellogenesis in Insects

“…The role of Kr-h1 in insect vitellogenesis varies among insect species. In L. migratoria, B. dorsalis, and the rice stem borer Chilo suppressalis, Kr-h1 mediates JH action to promote vitellogenesis and oocyte maturation (Song et al, 2014;Yue et al, 2018;Tang et al, 2020). In Ae.…”

RNAi‐based gene silencing in Phenacoccus solenopsis and its validation by in planta expression of a double‐stranded RNA

“…43,49 In previous studies, Kr-h1 has been extensively used in a wide range of hemimetabolous and holometabolous insects. [43][44][45][49][50][51][52][53][54][55][56] It appears to exert antimetamorphic action in these insects which protects them from precocious molting. 44,45,53,54 qRT-PCR data based on previous studies have shown that its expression varies with species and life stage.…”

“…It was first identified in Drosophila melanogaster as a homolog to a segmentation gene Krüppel , with homology in the zinc‐finger motifs 43,49 . In previous studies, Kr‐h1 has been extensively used in a wide range of hemimetabolous and holometabolous insects 43–45,49–56 . It appears to exert anti‐metamorphic action in these insects which protects them from precocious molting 44,45,53,54 .…”

Precocious Downregulation of Krüppel-Homolog 1 in the Migratory Locust, Locusta migratoria, Gives Rise to An Adultoid Phenotype with Accelerated Ovarian Development but Disturbed Mating and Oviposition

“…Moreover, in adult insects, JH transduces its signal via Met and Kr-h1. Multiple studies have confirmed the involvement of JH in vitellogenin synthesis in the fat body, lipid accumulation in the primary oocyte, regulation of mating and sex pheromone production in several insects [22][23][24][25][26][27][28][29][30][31][32][33][34][35][36]. Moreover, an effect on the number of eggs deposited could be attributed to JH as well, since a reduced number of eggs laid was observed upon silencing Met or Kr-h1 in the brown planthopper, N. lugens [22].…”