Submitted to: New Phytologist
Publication Type: Other
Publication Acceptance Date: 8/13/2003
Publication Date: 9/20/2003
Citation: RUNION, G.B. EFFECTS OF ELEVATED ATMOSPHERIC CARBON DIOXIDE ON PLANT PATHOSYSTEMS. NEW PHYTOLOGIST. 2003. Volume 159. Pgs. 531-538
Technical Abstract: This manuscript represents an invited commentary on a full-length article entitled, "How will plant pathogens adapt to host plant resistance at elevated CO2 under a changing climate?" written by Sukumar Chakraborty and Somnath Datta to be published in the journal New Phytologist. The manner in which increasing levels of atmospheric CO2 will affect crop diseases remains virtually unstudied. Chakraborty and Datta investigated the effects of ambient and twice-ambient levels of atmospheric CO2 on changes in aggressiveness, fecundity, and genotype of the anthracnose fungus, Colletotrichum gloeosporioides, when grown for 25 successive infection cycles on cultivars of the pasture legume, Stylosanthes scabra, varying in genetic resistance to the disease. The authors noted that aggressiveness of two isolates of the pathogen was initially reduced on both resistant and susceptible cultivars when grown under high CO2; however, following an initial lag phase of 10 infection cycles, aggressiveness increased on both cultivars, suggesting that enhanced resistance at elevated CO2 may not result in reduced host damage in the long term. The authors also observed an increase in fecundity (spores produced/lesion area) under elevated CO2 and noted that this increase could lead to an increase in the spread and severity of disease and has important implications for the functional duration of resistance in crop plants. Interestingly, while genotypic alterations occurred in both C. gloeosporioides isolates on the susceptible cultivar at twice-ambient CO2, these were not related to increased aggressiveness of the fungus. While this report represents one of only a few studies on the complex changes in plant pathosystems resulting from rising atmospheric CO2 concentration, it does provide evidence suggesting that elevated atmospheric CO2 can impact important crop pathosystems.