|SAWERS, RUAIRIDH - Centro De Investigacion
|SVANE, SIMON - University Of Copenhagen
|QUAN, CLEMENT - University Of Copenhagen
|GRONLUND, METTE - University Of Copenhagen
|WOZNIAK, BARBARA - University Of Lausanne
|GEBRESELASSIE, MESFIN - University Of Lausanne
|GONZALEZ-MUNOZ, ELIECER - Centro De Investigacion
|CHAVEZ MONTES, RICARDO - Centro De Investigacion
|GOUDET, JEROME - University Of Lausanne
|JAKOBSEN, IVER - University Of Copenhagen
|PASZKOWSKI, UTE - University Of Cambridge
Submitted to: New Phytologist
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 11/21/2016
Publication Date: 1/18/2017
Citation: Sawers, R., Svane, S., Quan, C., Gronlund, M., Wozniak, B., Gebreselassie, M.N., Gonzalez-Munoz, E., Chavez Montes, R., Baxter, I.R., Goudet, J., Jakobsen, I., Paszkowski, U. 2017. Phosphorus acquisition efficiency in arbuscular mycorrhizal maize is correlated with the abundance of root-external hyphae and the accumulation of transcripts encoding PHT1 phosphate transporters. New Phytologist. 214(2):632-643. doi:10.1111/nph.14403.
Interpretive Summary: Symbiosis with microbes is a key, but poorly understood, process for most plants to acquire nutrients from the soil. In this work, a panel of maize inbred lines, selected to maximize genetic diversity, was evaluated with and without inoculation with mycorrhizal fungi, one of the key symbiotic organisms. We measured multiple outputs to evaluate the effect of the fungus on the lines: plant growth, fungal morphology, transfer of phosphorus to the plant, plant element profiles and accumulation of transcripts plant phosphate transporters. The relative performance of lines changed between non-inoculated and inoculated plants which suggests that genetic factors in the plant contribute to symbiosis. Understanding these factors could allow the improvement of nutrient efficiency in a broad range of crops.
Technical Abstract: In light of the rising cost and often limited access to agricultural fertilizers, arbuscular mycorrhizas are attracting ever greater interest for their potential to promote more efficient use of the world's mineral resources. This potential remains largely unrealized, in part because of a lack of understanding of the factors determining the outcome of the symbiosis in any given context, and it remains to be demonstrated to what extent host genetic variation can drive the symbiosis in the direction of greater plant benefit under agricultural conditions. In this work, a panel of maize inbred lines, selected to maximize genetic diversity, was evaluated with and without inoculation with mycorrhizal fungi. In addition to measuring plant growth, fungal morphology, transfer of phosphorus to the plant, plant element profiles and accumulation of transcripts encoding the PHT1 family of plant phosphate transporters were also characterized. The relative performance of lines changed between non-inoculated and inoculated plants and it is proposed that such genotype x inoculation interaction is indicative of variation in host capacity to profit from symbiosis per se, and not only the result of differences in tolerance of low phosphate availability. The greatest growth response, observed in the line Oh43, was correlated with low arbuscule abundance but extensive development of extra-radical mycelium and fungal P transfer. The data suggest that host genetic factors influence fungal growth strategy with subsequent impact on the outcome of the symbiosis.