Synchronous vitellogenin expression and sexual maturation during migration are negatively correlated with juvenile hormone levels in Mythimna separata.

Hai-Jun Xiao,Xiao-Wei Fu,Kong-Ming Wu,Yong-Qiang Liu

doi:10.1038/srep33309

Hai-Jun Xiao, Xiao-Wei Fu + Show 2 more

Open Access

https://doi.org/10.1038/srep33309

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Abstract

Annual migration of pests between different seasonal habitats can lead to serious crop damage. Reproductive immaturity is generally associated with the migratory process (oogenesis-flight syndrome), but the mechanism of reproductive development during migration varies unpredictably. Here, the vitellogenin gene (MsVg) and three key regulatory enzyme genes (MsJhamt, MsJheh and MsJhe) related to juvenile hormone (JH) synthesis and degradation were identified and characterized in Mythimna separata. The relative expression of MsVg varied significantly in response to seasonal changes and was significantly correlated with stages of ovarian development. The relatively low levels of JH titer did not differ significantly in male moths but slightly increased in female adults during the migratory season, which was consistent with changes in mRNA levels for MsJhamt, MsJheh and MsJhe. JH titer was negatively associated with relative seasonal levels of vitellogenin mRNA transcripts and with ovarian development in migrating M. separata. The synchrony of MsVg expression with sexual maturation highlighted the potential of MsVg transcript levels to serve as an index to monitor the adult reproductive status. In addition, the level of JH and sexual maturity were correlated with the extent of JH in regulating the MsVg expression and reproduction during seasonal northern and southern migration.

Highlights

Annual migration of pests between different seasonal habitats can lead to serious crop damage
Linear regression analyses revealed that the seasonal juvenile hormone (JH) titer was positively correlated with mRNA transcript levels for Jhamt, Jheh and Jhe, except for Jhe in female moths (Figure S5)
In a linear regression analysis between the monthly JH titer as the dependent variable and the transcript level of Jhamt, Jheh or Jhe as an independent variable, the seasonal JH titer was positively correlated with mRNA transcript levels for Jhamt, Jheh and Jhe (Figure S6), except for Jhe in female moths

Summary

Introduction

Annual migration of pests between different seasonal habitats can lead to serious crop damage. The oriental armyworm Mythimna separata (Walker) (Lepidoptera: Noctuidae) is a serious migratory insect pest in Asia[1] on Poaceae species such as Zea mays (maize), Triticum aestivum (wheat), and Oryza sativa (rice), and its outbreaks have caused large-scale crop losses in China over the last three years[2]. Seasonal outbreaks of this pest often occurs in northern and northeastern areas in warm climates. Juvenile hormone is of great importance throughout the lifespan of www.nature.com/scientificreports/

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