Elevated CO and temperature under future climate change increase severity of rice sheath blight.

Sheath blight (ShB), caused by , is one of the major threats to rice ( L.) production. However, it is not clear how the risk of rice ShB will respond to elevated CO and temperature under future climate change. Here, we conducted, field experiments of inoculated under combinations of two CO levels (ambient and enriched up to 590 μmol mol) and two temperature levels (ambient and increased by 2.0°C) in temperature by free-air CO enrichment (T-FACE) system for two cultivars (a susceptible cultivar, Lemont and a resistant cultivar, YSBR1). Results indicate that for the inoculation of plants with , the vertical length of ShB lesions for cv. Lemont was significantly longer than that for cv. YSBR1 under four CO and temperature treatments. The vertical length of ShB lesions was significantly increased by elevated temperature, but not by elevated CO, for both cultivars. The vertical length of ShB lesions under the combination of elevated CO and elevated temperature was increased by 21-38% for cv. Lemont and by -1-6% for cv. YSBR1. A significant increase in MDA level was related to a significant increase in the vertical length of ShB lesions under the combination of elevated CO and elevated temperature. Elevated CO could not compensate for the negative effect of elevated temperature on yield of both cultivars under future climate change. Rice yield and biomass were further decreased by 2.0-2.5% and 2.9-4.2% by an increase in the severity of ShB under the combination of elevated CO and elevated temperature. Thus, reasonable agronomic management practices are required to improve both resistance to ShB disease and grain yield for rice under future climate change.