Reciprocal plant-mediated interactions between a virus and a non-vector herbivore

Area of Science:

• Plant pathology
• Insect-plant interactions
• Ecology

Background:

• Vector-borne plant viruses alter host traits, influencing vector behavior and transmission.
• The impact of plant viruses on non-vector herbivores and vice-versa is less understood.
• Plant-mediated interactions are crucial in pathogen and vector dynamics within diverse communities.

Purpose of the Study:

• To investigate the reciprocal interactions between Pea enation mosaic virus (PEMV) and the non-vector weevil, Sitona lineatus.
• To determine if PEMV influences S. lineatus behavior and fitness.
• To assess if S. lineatus herbivory affects PEMV infection dynamics and transmission.

Main Methods:

• Field observations of plant defoliation by S. lineatus on PEMV-infected and uninfected plants.
• Behavioral assays to assess S. lineatus feeding preferences.
• Quantification of PEMV titer in plants subjected to different herbivory and virus treatments.
• Measurement of plant phytohormone levels (jasmonic acid, salicylic acid, abscisic acid).

Main Results:

• PEMV-infected plants experienced greater defoliation by S. lineatus.
• S. lineatus adults showed a preference for feeding on PEMV-infected plants.
• Aphid vector (Acyrthosiphon pisum) preference increased for plants damaged by S. lineatus.
• S. lineatus herbivory led to elevated PEMV titers.
• Distinct phytohormone responses were observed: S. lineatus induced jasmonic acid, PEMV induced salicylic acid, and both together elevated abscisic acid.

Conclusions:

• Non-vector herbivores can be influenced by plant viruses, potentially increasing virus spread.
• Herbivore damage can enhance virus levels and vector attraction, creating a positive feedback loop.
• Phytohormone signaling plays a role in mediating these complex plant-virus-herbivore interactions.
• Understanding these multi-trophic interactions is vital for managing plant pathogens and their vectors.