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Update:August 23, 2018

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An insect virus modulates host metamorphosis by encoding an enzyme that regulates juvenile hormone synthesis


Article title

A virus carrying the gene encoding juvenile hormone acid methyltransferase, a key regulatory enzyme in insect metamorphosis

Author (affiliation)

Jun Takatsuka(a), Madoka Nakai(b), Tetsuro Shinoda(c)

(a) Department of Forest Entomology, FFPRI, Tsukuba, Ibaraki, Japan.
(b) Tokyo University of Agriculture and Technology, Fuchu, Tokyo, Japan.

(c) National Agriculture and Research Organization, Tsukuba, Ibaraki, Japan.

Publication Journal

Scientific Reports, 7(1) 13522, October 2017, DOI: 10.1038/s41598-017-14059-8( External link )

Content introduction

The development of a serious forest pest necessitates the consideration of using pesticides that are safe for humans and the environment. Metamorphosis is defined as a set of changes that occur during insect growth—from larva to pupa and then to adult. The mechanism underlying these changes differs from that in vertebrates. Therefore, the discovery of a method for preventing insect-specific development may lead to the development of insect-specific chemicals. Hormones such as the juvenile hormone, which maintains the larval stage, are involved in insect metamorphosis. The juvenile hormone synthetic pathway(note 1) is present only in insects.

To the best of our knowledge, this is the first study to reveal that an entomopoxvirus(note 2) carries a gene encoding an enzyme that synthesizes juvenile hormone. This enzyme is produced within the infected larvae and synthesizes juvenile hormone using molecules derived from the juvenile hormone synthetic pathway of insects. The virus prevents normal insect metamorphosis by modulating the juvenile hormone synthetic pathway; the juvenile hormone level in the insects significantly increases, thus inhibiting the transition from larval to pupal stage. As a result, the insects die in the larval stage.

The results are useful in elucidating the fundamental structure of the juvenile hormone-synthesizing enzyme. This may lead to the development of novel chemicals, so called juvenile hormone synthesis inhibitors, which would be non-toxic to organisms other than insects.


Note 1) The juvenile hormone synthetic pathway: Pathway for synthesizing juvenile hormone using mevalonic acid as the starting compound. In the final step, juvenile hormone acid is modified for producing juvenile hormone.

Note 2) Entomopoxvirus: The virus belongs to the family Poxviridae, which infects insects. The viruses are isolated from various insects including butterflies, locusts, and beetles.


Photo 1 Entomopoxvirus
Photo 1 Entomopoxvirus


 Fig. 1 An overview of the study

Fig. 1 An overview of the study