Virus disease in wheat predicted to increase with a changing climate

Abstract

Current atmospheric CO 2 levels are about 400 lmol mol À1 and are predicted to rise to 650 lmol mol À1 later this century. Although the positive and negative impacts of CO 2 on plants are well documented, little is known about interactions with pests and diseases. If disease severity increases under future environmental conditions, then it becomes imperative to understand the impacts of pathogens on crop production in order to minimize crop losses and maximize food production. Barley yellow dwarf virus (BYDV) adversely affects the yield and quality of economically important crops including wheat, barley and oats. It is transmitted by numerous aphid species and causes a serious disease of cereal crops worldwide. This study examined the effects of ambient (aCO 2 ; 400 lmol mol À1 ) and elevated CO 2 (eCO 2 ; 650 lmol mol À1 ) on noninfected and BYDV-infected wheat. Using a RT-qPCR technique, we measured virus titre from aCO 2 and eCO 2 treatments. BYDV titre increased significantly by 36.8% in leaves of wheat grown under eCO 2 conditions compared to aCO 2 . Plant growth parameters including height, tiller number, leaf area and biomass were generally higher in plants exposed to higher CO 2 levels but increased growth did not explain the increase in BYDV titre in these plants. High virus titre in plants has been shown to have a significant negative effect on plant yield and causes earlier and more pronounced symptom expression increasing the probability of virus spread by insects. The combination of these factors could negatively impact food production in Australia and worldwide under future climate conditions. This is the first quantitative evidence that BYDV titre increases in plants grown under elevated CO 2 levels.

Vector population growth and condition‐dependent movement drive the spread of plant pathogens

“…Although studies are beginning to emerge assessing the effect of climate change on viruses and vectors (e.g., Trębicki et al. ), additional studies with other pathosystems are merited. Data from such studies will in turn enhance future modeling exercises like ours.…”

Water deficit enhances the transmission of plant viruses by insect vectors

“…Among these studies, those concerning viruses have long focused either on the vector biology (e.g. developmental time, longevity, fecundity, migration) and ecology [12–14], or on the virus accumulation and symptom expression in planta [15–17]. While most of these studies speculate on a possible impact of environmental changes on the rate of virus transmission, direct experimental support was totally lacking, or not statistically tested [18], until very recently [19, 20].…”

Challenges and Responses to Ongoing and Projected Climate Change for Dryland Cereal Production Systems throughout the World

“…For cropping in areas of higher precipitation, the management of pests and disease will likely be an added burden especially as the atmospheric CO 2 levels rise. For example, Trebicki et al found that under these conditions barley yellow dwarf virus will spread more quickly in infected wheat crops [99]. Globally, research on insect pests of wheat under climate change remains limited despite the potential of pests to reduce yields and increase yield variability [100].…”