Effects of Intercropping and Plant Variety on Root Fungal Community

Summary

Increasing environmental awareness has put new attentions on cereal-legume inter cropping system as a possible way to diversify agricultural fields and to efficiently produce food and feed under increasingly adverse conditions caused by climate change. The choice of mixing partners drives plant functional complementarities. In this context, elucidating the effects of this pairing on the plant-associated microbial community can help to better understand and, thus, optimize intercropping sys tems. This MSc project seeks to understand belowground microbial interactions in intercropping through examining organically-managed cereal-legume on-farm exper iments, including a pea (Pisum sativum L.)-barley (Hordeum vulgare L.) experiment in Switzerland (CH) and a pea-wheat (Triticum aestivum L.) experiment in Hungary (HU). Root fungal communities of different varieties in pure and intercropping systems were investigated based on Illumina MiSeq sequencing of the ITS1 gene. In the Swiss pea-barley experiment, five pea varieties (Alvesta, Karpate, Mytic, Respect, Vitra) each mixed with one barley variety (Atrika) were examined; in the Hungarian wheat-pea experiment, three wheat varieties (Kolompos, Kompozit, Nador) each mixed with one pea variety (Aviron) were examined. Across all varieties, intercropping did not have an effect on alpha fungal diversity. However, there were first indications for variety by cropping system effects on alpha diversity. Fungal richness of roots of particular pea varieties was influenced by the cropping partner either on a species level (CH experiment) or on a genotype level (HU experiment). Pielou’s evenness and Shannon diversity in pea roots were influenced by pea variety. Similarly, the analysis of beta diversity also showed intercropping, across all varieties, did not have an effect on root fungal community, for both experiments. A significant crop variety effect was observed for the CH experiment showing distinct fungal community compositions for the pea varieties Respect, Alvesta and Vitra. This study also identified fungal taxa, including putative pea pathogens and beneficials (e.g. Glomeromycota), associated with certain crop varieties and their change in abundances by intercropping. Lastly, the relation between variety fungal community characteristics and their agronomic traits could provide further insights in understanding this complex plant-plant-microbiome interactions.