Abiotic Factors Affecting Vector-Borne Plant Pathogen Complexes: Elevated CO₂ and the Barley Yellow Dwarf Pathosystem

Area of Science:

• Plant Science
• Agronomy
• Environmental Science

Background:

• Atmospheric CO₂ changes affect plant physiology and interactions with biotic factors.
• Barley yellow dwarf virus (BYDV), transmitted by the cereal aphid Rhopalosiphum padi, is a significant pathogen of small grains.
• Cultivated and uncultivated Poaceae species serve as hosts for BYDV and its aphid vector.

Purpose of the Study:

• To investigate the impact of elevated CO₂ on plant physiology, Rhopalosiphum padi performance, and BYDV accumulation.
• To assess these effects across different host plants: winter wheat, foxtail barley, and green foxtail.
• To understand the role of elevated CO₂ in virus dynamics and host-pathogen interactions.

Main Methods:

• A controlled growth chamber experiment was conducted using ambient (420 ppm) and elevated (700 ppm) CO₂ conditions.
• Plants were subjected to aphid infestation (Rhopalosiphum padi) to monitor BYDV (strain BYDV-PAV) accumulation.
• Measurements included plant biomass, aphid survival and reproduction, transpiration rates, carbohydrate concentration, and virus titers.

Main Results:

• Elevated CO₂ significantly increased total plant biomass in all tested species.
• Aphid survival and reproduction were not affected by elevated CO₂ levels.
• BYDV-PAV accumulation increased under elevated CO₂ across all host plant species, with winter wheat showing the highest virus titer.

Conclusions:

• Elevated CO₂ enhances BYDV accumulation in small grains and grasses, potentially increasing disease pressure.
• Uncultivated grasses act as crucial reservoirs for BYDV and its vector, Rhopalosiphum padi.
• Future management strategies and predictions for BYDV dynamics must consider the influence of elevated CO₂ and non-crop host plants.