Importance of the Host Phenotype on the Preservation of the Genetic Diversity in Codling Moth Granulovirus.

Graillot Graillot,Siegwart Siegwart,Besse Besse,López-Ferber López-Ferber,Blachere-López Blachere-López

doi:10.3390/v11070621

Graillot Graillot, Siegwart Siegwart + Show 3 more

Open Access

https://doi.org/10.3390/v11070621

Copy DOI

Abstract

To test the importance of the host genotype in maintaining virus genetic diversity, five experimental populations were constructed by mixing two Cydia pomonella granulovirus isolates, the Mexican isolate CpGV-M and the CpGV-R5, in ratios of 99% M + 1% R, 95% M + 5% R, 90% M + 10% R, 50% M + 50% R, and 10% M + 90% R. CpGV-M and CpGV-R5 differ in their ability to replicate in codling moth larvae carrying the type I resistance. This ability is associated with a genetic marker located in the virus pe38 gene. Six successive cycles of replication were carried out with each virus population on a fully-permissive codling moth colony (CpNPP), as well as on a host colony (RGV) that carries the type I resistance, and thus blocks CpGV-M replication. The infectivity of offspring viruses was tested on both hosts. Replication on the CpNPP leads to virus lineages preserving the pe38 markers characteristic of both isolates, while replication on the RGV colony drastically reduces the frequency of the CpGV-M pe38 marker. Virus progeny obtained after replication on CpNPP show consistently higher pathogenicity than that of progeny viruses obtained by replication on RGV, independently of the host used for testing.

Highlights

Codling moth, the main insect pest for apple and pear production [1], is widely distributed around the world
We have investigated the ability of mixes of Cydia pomonella granulovirus (CpGV)
Larvae were reared on media containing 100 occlusion body (OB)/μL of CpGV-M until pupation; adults that emerged were allowed to mate, the eggs collected, and the new generation of larvae submitted to the same process

Summary

Introduction

The main insect pest for apple and pear production [1], is widely distributed around the world. Most apple production areas suffer damages caused by this insect [2]. The necessity of alternative methods becomes evident. Baculoviruses are authorized as biological control agents in field conditions because they are specific to one or few insect species and harmless for beneficial insects [4]. The first Cydia pomonella granulovirus (CpGV) isolate originates from Mexico (CpGV-M) [5]. This isolate is one of the most widely-used GV for biological control; it is considered as the reference isolate, and a representative clone of this isolate has been completely sequenced [6]. In Europe, all commercial formulations of CpGV before 2008 were derived from it [7]

Methods

Results

Conclusion