Impact of pea-wheat intercropping on grain ionome in relation with changes in Pseudomonas spp. and Enterobacterales abundance in the rhizosphere. POSiTiF_WP3

Cereal-legume intercropping (IC) has been proposed to meet the challenges of increasing yields and improving crop nutrient quality, which are crucial for both food security and human health. Legumes, in particular, are of great interest, as they can fix atmospheric nitrogen, thus reducing the need for N-fertilizers. This study aimed to characterize the impact of pea-wheat IC on grain ionome composition, and asses a possible relation with the abundance of Pseudomonas spp. and Enterobacterales in plant roots, two groups involved in Fe, Mg and P mobilization. In a field experiment, four pea (Pisum sativum) varieties were cultivated in sole- or intercropping with wheat (Triticum aestivum) in two different soil types. Grain ionome was characterised by mass spectrometry. Pseudomonas spp. and Enterobacterales abundances were determined by qPCR. A positive correlation was found between the increased abundance of Pseudomonas spp. and higher Mo content in IC peas. Enterobacterales increased in IC wheat and were positively correlated with Mn, Fe, and Cu grain content. Mg, Ca, Ni and Mn were also increased in IC peas, while Cu, Fe, S, Zn, N, C and Mn were increased in IC wheat. These findings show that IC may favour the concentration of specific ions in pea and wheat grains. This enhancement was related to an increased abundance of Pseudomonas spp. in IC. Further research is necessary to understand the underlying mechanisms behind element accumulation in IC grains and to explore the potential benefits of intercropping on plant nutrition and growth.