Changes in leaf microbiome linked to disease susceptibility

Plant pathogens cause significant losses to crop production, but they represent only a small fraction of the microbiome populating crops. Little is know about the effects of the majority of non-pathogenic microbes on the crop fitness. Using molecular tools, it was shown that the leaf-associated bacterial populations differed between barley accessions (commercialised cultivars and landraces). Leaves were collected from tussocks grown in the field, which were visually scored for the following diseases: leaf scald, powdery mildew and ramularia leaf spot (RLS). Plants with high amount of leaf scald had low bacterial diversity, whereas the opposite trend was observed in plants with high amount of mildew and RLS. Landraces also showed a larger variability in bacterial diversity than cultivars. The genetic variability of landraces could be mined for crop breeding to achieve more sustainable disease management through phyllosphere manipulation.