Effect of Elevated CO2 Concentration on the Disease Severity of Compatible and Incompatible Interactions of Brassica napus–Leptosphaeria maculans Pathosystem

摘要

Global warming by increased atmospheric CO concentration has been widely accepted. Yet, there has not been any consistent conclusion on the doubled CO concentration that in the future will affect plant disease incidence and severity. Blackleg disease, mainly caused by , is a major disease on canola production globally. and have a gene-for-gene interaction, which causes an incompatible reaction between canola plants carrying resistance genes and isolates carrying corresponding avirulence genes. In this study, varieties and lines inoculated with different isolates were subjected to simulated growth conditions, namely, growth chambers with normal environments and with controlled CO concentrations of 400, 600, and 800 ppm. The results indicated that the elevated CO concentrations have no noticeable effect on the inferred phenotypes of the canola–blackleg interactions. However, the disease severity decreased in most of the – interactions at extremely high CO concentration (800 ppm). The varied pathogenicity changes of the pathosystem under elevated CO concentrations at 400 or 600 ppm may be due to the genetic background or physiological differences in plants and pathogenicity differences in isolates having different gene profiles. The mechanisms by which elevated CO concentrations affect the pathosystem will help us understand how climate change will impact crops and diseases.