Potato's little helpers

One of the objectives of SolACE is to evaluate the efficiency of water and nutrient acquisition of different potato genotypes by defining the relevant below-ground traits. Important traits that should not be overlooked are related to the rhizosphere and root microbiome. Their large number of bacteria and fungi are major drivers for both nutrient cycling in the soil and the formation of good soil structure. 
By evaluating the diversity and functional potential of the soil microbiome in the rhizosphere of potatoes, the Austrian Institute of Technology (AIT) and the Research Institute of Organic Agriculture (FiBL) aim to improve the selection of potato genotypes able to cope with combined water and nutrient limitations. 
We evaluated the performance of ten potato genotypes grown either with or without the combined stresses of nutrient and water deficit in a field trial at the James Hutton Institute in Dundee, Scotland. Using amplicon sequencing of phylogenetic marker genes and shotgun metagenomics, we analysed how plant genotype, plant phenotype and the different stress scenarios affected bacterial and fungal microbiota in the root environment. We observed that selected bacterial groups, as well as the diversity and richness in general, were reduced in the rhizosphere of potatoes grown under stressed conditions. We found that the bacterial community changed greatly within the root under stress. However, the fungal community did not change as substantially. Shared, unique and differently abundant microbial amplicon sequencing variants (“microbial taxa”) indicated a stress- and genotype-specific recruitment of microbes by potato plants. The results of this trial will help to identify below-ground traits and select efficient potato genotypes which are best suited to cope with combined stress scenarios, whilst simultaneously supporting beneficial functions of the soil microbiome.