Cucumber Mosaic Virus Degrades Pepper Fruit Production, Marketability and Organoleptic Quality, With Isolate-Specific Effects

Over the past decade, recurrent epidemics of cucumber mosaic virus (CMV) have damaged Espelette pepper crops, a product from the French Basque Country with a Protected Designation of Origin (PDO). Of the three main CMV phylogenetic groups, isolates from Subgroup IB seem to be responsible for these epidemics, while Group II is only sporadically present and Subgroup IA is completely absent, although common elsewhere in France. This study quantifies the impact of three CMV isolates belonging to (Sub)groups IA, IB, and II on the production and quality of Espelette pepper (Capsicum annuum 'Gorria'). The CMV-susceptible inbred line Yolo Wonder was also included as a reference. First, we monitored fruit production dynamics (number and weight) and found that infection by the IA isolate significantly reduced total yield in both cultivars, while infections by the IB and II isolates had milder or nonsignificant effects. Secondly, we assessed the marketability of Gorria fruits under the PDO label by monitoring defects in size, shape and colour. Infected plants produced significantly shorter, more misshapen and discoloured fruits, especially with infection by isolate IA. Finally, we evaluated the organoleptic properties of infected Gorria fruits thanks to a jury trained in PDO quality standards. Peppers infected with the IA isolate were significantly more likely to be rejected compared to healthy controls. Our results underline that CMV infection degrades both pepper yield and quality, with severity depending on pepper cultivar and CMV isolate. In Espelette, managing current epidemics and preventing the introduction of IA isolates is thus crucial.