Virus infection mediates the effects of elevated CO2 on plants and vectors

Abstract

Atmospheric carbon dioxide (CO2) concentration has increased significantly and is projected to double by 2100. To increase current food production levels, understanding how pests and diseases respond to future climate driven by increasing CO2 is imperative. We investigated the effects of elevated CO2 (eCO2) on the interactions among wheat (cv. Yitpi), Barley yellow dwarf virus and an important pest and virus vector, the bird cherry-oat aphid (Rhopalosiphum padi), by examining aphid life history, feeding behavior and plant physiology and biochemistry. Our results showed for the first time that virus infection can mediate effects of eCO2 on plants and pathogen vectors. Changes in plant N concentration influenced aphid life history and behavior, and N concentration was affected by virus infection under eCO2. We observed a reduction in aphid population size and increased feeding damage on noninfected plants under eCO2 but no changes to population and feeding on virus-infected plants irrespective of CO2 treatment. We expect potentially lower future aphid populations on noninfected plants but no change or increased aphid populations on virus-infected plants therefore subsequent virus spread. Our findings underscore the complexity of interactions between plants, insects and viruses under future climate with implications for plant disease epidemiology and crop production.

The Contrasting Effects of Elevated CO2 on TYLCV Infection of Tomato Genotypes with and without the Resistance Gene, Mi-1.2

“…Previous research has demonstrated that vector-borne viruses can modify vector behavior and fitness and thereby enhance virus spread by altering the host plant traits. For example, the virus could increase the nutritional quality of infected host plants, decrease the resistance of infected host plants, or increase the attractiveness of infected plants to their vectors (Jiménez-Martínez et al, 2004; Luan et al, 2013; Trêbicki et al, 2016). Infection by TYLCCNV, for example, suppresses JA-induced defenses in tomato plants, which increases the feeding and the fitness of the whitefly vector, which in turn enhances the transmission of the virus (Zhang et al, 2012).…”

Insect–plant–pathogen interactions as shaped by future climate: effects on biology, distribution, and implications for agriculture

“…Elevated CO 2 also increased R. padi weight and growth rates on wheat (Sun et al ., ; Oehme et al ., ). On the contrary, a negative response was found in A. pisum abundance on Vicia faba L. and R. padi on Schedonorus arundinaceus Schreb (Hughes & Bazzaz, ; Ryan et al ., ) and wheat (Trębicki et al ., ). Results suggested that eCO 2 was also detrimental for M. persicae overall fitness and adult weight on brassicaceae and A. gossypii on Capsicum annuum L. (Stacey & Fellowes, ; Himanen et al ., ; Oehme et al ., ; Dáder et al ., ).…”

“…These changes can either facilitate or reduce insect outbreaks, which are often specific to a particular insect exposed to a particular host. Increases in insect numbers, particularly vectors of plant pathogens, would likely increase the spread of viruses or bacteria that they transmit (Trębicki et al ., , ; Jones, ). Predicting the direct effect of differential climate change scenarios on insect pests and plant diseases is complex.…”

“…The feeding behavior of insect vectors, particularly aphids, has been monitored under rising CO 2 by the electrical penetration graph (EPG) technique (Dáder et al ., ; Trębicki et al ., ), which provides a live real time visualization of plant penetration by insect mouthparts (Tjallingii, ; Trębicki et al ., ). Decreased salivation into sieve elements, increased phloem sap ingestion and shorter nonpathway phase are among the responses observed for the aphid A. pisum on M. truncatula and M. persicae on C. annuum (Guo et al ., ; Dáder et al ., ).…”

“…It is very likely that abiotic factors including temperature, CO 2 and rainfall will differentially affect insects, plants and pathogens under future climates. It is also reasonable to predict that the interactions between them may be altered, as was observed for aphids and virus in wheat (Trębicki et al ., ), leading to changes in the severity of both insects and pathogens on the host plant. Other pathogens (such as fungi), which are not necessarily transmitted by insects, but rather coinfect the host together with the insects, can also significantly impact the plant and/or the insect itself, however, these effects are not well understood.…”