Improved resistance to stress and absorption of phosphate through symbiosis | Umweltbundesamt

The agriculture of the future is facing great challenges, as already noticeable and possibly increasing climate changes lead to an accumulation of unfavorable weather events, which affect the growth and yield of crops. At the same time, artificial fertilizers have to be saved as the phosphate contained is scarce worldwide and the leaching of phosphates from farmland pollutes the environment. Sustainable, promising agriculture requires the cultivation of cultivars that are both stress-resistant and nutrient-rich.

The arbuscular mycorrhiza (AM) is a widespread symbiosis between land plants and special soil fungi. This symbiosis improves nutrient uptake and stress resistance - especially against drought stress - of plants. Arbuscular mycorrhiza increases grain yield in some maize lines under drought stress and phosphate hunger. Investigations show that the extent of the AM-dependent increase in performance of the plant, the so-called "AM-responsiveness", depends on the plant variety. The genetic basis of AM responsiveness is currently unknown.

The project aimed to use the relatively well-researched genetic diversity of maize to contribute to the selection and breeding of AM-optimized crop varieties. For this purpose, the AM-mediated drought resistance, phosphate uptake and performance of 16 European maize inbred lines and control varieties were tested in field trials and in the field trials Greenhouse compared. Individual differences in AM-responsiveness between the investigated lines as well as between the environments were found and optimal AM-responsive maize varieties could be identified for the different site conditions tested. The lines benefited significantly from the treatment with AM fungi, especially under drought and low phosphate conditions. These differences in AM responsiveness will be used in the future to identify genomic regions responsible for the quantitative differences in AM responsiveness. The knowledge of these genome regions can be used for the targeted marker-based breeding of symbiosis-optimized plants. Arbuscular mycorrhiza increases grain yield in some maize lines under drought stress and phosphate hunger. The response to mycorrhiza depends on the corn genotype. The variation in the mycorrhiza response promises possibilities for breeding optimization. The experiment in the LemnaTec facility showed differences between the lines in the mycorrhiza-activated growth dynamics.