Manipulation of Aphid Behavior by a Persistent Plant Virus

Area of Science:

• Plant pathology
• Virology
• Entomology
• Chemical ecology

Background:

• Persistent, asymptomatic plant viruses are vertically transmitted and spread via host cell division.
• Jalapeño peppers (Capsicum annuum) are universally infected with Pepper cryptic virus 1 (PCV-1).
• Aphids (Myzus persicae) are vectors for acute plant viruses, often attracted by virus-induced volatile emissions.

Purpose of the Study:

• To investigate the effect of PCV-1 on aphid (Myzus persicae) behavior and host plant quality.
• To compare the behavioral manipulation of aphids by a persistent virus (PCV-1) versus an acute virus (Cucumber mosaic virus, CMV).

Main Methods:

• Pairwise preference experiments using odor cues from PCV-1-infected (J+) and virus-free (J-) jalapeño peppers.
• Inoculation of J+ and J- plants with CMV to assess aphid attraction to volatiles.
• Measurement of aphid reproduction on J+ and J- plants.

Main Results:

• PCV-1-infected plants deterred aphids, contrasting with acute virus-infected plants that attract vectors.
• While CMV-infected plants attracted aphids, aphids preferred virus-free plants when offered a choice between J+ CMV- and J- CMV-infected plants.
• Aphid reproduction was over twofold lower on PCV-1-infected plants compared to virus-free plants.

Conclusions:

• Persistent plant viruses, like PCV-1, can manipulate aphid behavior to deter them, offering plant protection.
• This contrasts with acute viruses that manipulate hosts to attract vectors, facilitating transmission.
• PCV-1 confers a benefit to Capsicum annuum by reducing aphid herbivory and protecting against other virus vectors, with implications for agricultural pest management.