Characterization of Durum Wheat Resistance against Septoria Tritici Blotch under Climate Change Conditions of Increasing Temperature and CO2 Concentration

Abstract

Wheat interactions against fungal pathogens, such as Zymoseptoria tritici, are affected by changes in abiotic factors resulting from global climate change. This situation demands in-depth knowledge of how predicted increases in temperature and CO2 concentration ([CO2]) will affect wheat—Z. tritici interactions, especially in durum wheat, which is mainly grown in areas considered to be hotspots of climate change. Therefore, we characterized the response of one susceptible and two resistant durum wheat accessions against Z. tritici under different environments in greenhouse assays, simulating the predicted conditions of elevated temperature and [CO2] in the far future period of 2070–2099 for the wheat-growing region of Córdoba, Spain. The exposure of the wheat—Z. tritici pathosystem to elevated temperature reduced disease incidence compared with the baseline weather conditions, mainly affecting pathogen virulence, especially at the stages of host penetration and pycnidia formation and maturation. Interestingly, simultaneous exposure to elevated temperature and [CO2] slightly increased Z. tritici leaf tissue colonization compared with elevated temperature weather conditions, although this fungal growth did not occur in comparison with baseline conditions, suggesting that temperature was the main abiotic factor modulating the response of this pathosystem, in which elevated [CO2] slightly favored fungal development.