Inability of the brown citrus aphid (Toxoptera citricida) to transmit citrus psorosis virus under controlled conditions

Lester Hernandez-Rodriguez,Diego Maeso,Ana Bertalmio,Leticia Rubio,Rodolfo Roque,Fernando Rivas

doi:10.5070/c471045702

Abstract

Might Toxoptera citricida (BrCA) be a citrus psorosis virus (CPsV) vector? We examined CPsV transmission by the BrCA throughout two experiments. In experiment 1, 4 CPsV-infected plants bearing BrCA colonies were introduced in separated cages with 12 healthy 'Madame Vinous' sweet orange (MV) seedlings in each one (48 in total). In experiment 2, 5 BrCAs collected from each CPsV-infected plant were transferred into 3 MV seedlings for each one (12 in total) and left for a 72-h inoculation period. Both experiments were replicated once. No psorosis symptoms or CPsV detection evidences a BrCA inability for CPsV transmission under our controlled conditions.

Highlights

Citrus psorosis virus (CPsV; Aspiviridae, Ophiovirus) is the causal agent of citrus psorosis, an ancient citrus disease (García et al 2017)
All CPsV source plants showed shock reaction consisting in leaf shedding and necrosis of the new shoots at the beginning and during the experiments; distinctive symptoms of psorosis disease in sweet oranges (Figure 2 A) (Moreno et al 2015)
CPsV was not detected in RT-PCR assays in any of the aphid-inoculated Madame Vinous' sweet orange (MV) seedlings in either experiments

Summary

Introduction

Citrus psorosis virus (CPsV; Aspiviridae, Ophiovirus) is the causal agent of citrus psorosis, an ancient citrus disease (García et al 2017). The dispersion of CPsV has been mediated by the vegetative propagation of infected tissues, a natural dispersal of the virus has been presumed (García 2012; Moreno et al 2015). It is well known that some ophioviruses are soil-transmitted by a root-infecting oomycete of the Olpidium genus (García et al 2017). In the case of CPsV, RT-PCR analysis showed the presence of CPsV RNA1 sequences in zoospores from an Olpidiumlike fungus, infecting the roots of healthy or CPsV-infected grapefruit trees in Texas (Palle et al 2005). Some trials adding viruliferous zoospores to healthy seedlings failed to transmit CPsV (Palle et al 2005)

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