Endosymbionts Differentially Alter Exploratory Probing Behavior of a Nonpersistent Plant Virus Vector

Area of Science:

• Plant pathology
• Insect-microbe interactions
• Epidemiology

Background:

• Insect endosymbionts can alter vector physiology and behavior, influencing plant virus epidemiology.
• The role of symbionts in nonpersistent plant virus transmission, which relies on transient mouthpart contamination, is largely unknown.
• Nonpersistent virus transmission occurs during exploratory feeding probes.

Purpose of the Study:

• To investigate the effect of facultative intracellular symbionts on the probing behavior of the cowpea aphid, Aphis craccivora, a vector of cucurbit viruses.
• To determine how symbiont infection influences exploratory intracellular punctures during host plant assessment.
• To assess the impact of symbionts on aphid probing in the context of nonpersistent virus transmission.

Main Methods:

• Utilized electrical penetration graphing (EPG) to monitor aphid probing behavior.
• Compared probing frequency and initiation speed in four A. craccivora isolines: two infected with symbionts (Arsenophonus sp. and Hamiltonella defensa) and their cured counterparts.
• Evaluated probing on both healthy and watermelon mosaic virus-infected pumpkin plants.

Main Results:

• Symbiont infection differentially affected aphid probing behavior: H. defensa reduced probing, while Arsenophonus increased it.
• Aphids exhibited increased probing on virus-infected plants, suggesting a virus-induced manipulation of vector behavior.
• Exploratory intracellular puncture frequency was significantly modified by symbiont presence.

Conclusions:

• Facultative symbionts differentially influence plant-host exploration behaviors in insect vectors.
• Symbiont-mediated changes in probing behavior may impact the transmission efficiency of nonpersistent plant viruses.
• Plant viruses may manipulate vector probing to enhance their acquisition and transmission rates, irrespective of symbiont infection.