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bioRxiv · 10.64898/2025.12.17.694934

Previous legume identity influences wheat protein content through organic matter depolymerization

L'Esperance, E.·Poirier, V.·Lavergne, S.·Yergeau, E.
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Abstract

In crop rotation systems, plant-soil feedback (PSF) effects can modulate nutrient cycling in soil, like organic carbon (C) and nitrogen (N) cycling. Organic nitrogen is present in plant and microbial necromass, and it must be depolymerized by microbes to become available for crops. Since plant identity can modulate microbial diversity and community composition, we thought that previous crop identity and its residue management would also change the microbial functional capacity, and thereby impact soil N availability, and the quality and yield of the following crop. To test this, two legumes (Vicia faba L., i.e. faba bean, and Pisum sativum L., i.e., yellow pea) were grown in two fields (Cloutier, and Palmarolle) in Abitibi-Temiscamingue, Quebec, Canada (n=3 for each field). At the end of the growing season, we harvested peas and faba beans in both fields. During the following growing season, spring wheat (Triticum aestivum L.) was sown and received, or not granulated chicken manure as an organic fertilizer. We determined the diversity and composition of the microbial communities and their enzymatic depolymerization capacity in the soil and the rhizosphere each growing season. During wheat growth, previous legumes shaped bacterial (p-value = 0.006) and fungal (p-value = 0.001) communities without modulating the enzymatic activity of wheat-associated rhizosphere microbes. However, faba bean as a previous crop increased soil ammonium and wheat grain protein content at harvest as compared to peas at Cloutier. Altogether, our results show that faba beans can enhance wheat N nutrition, without a concomitant increase in potential protein or cellulose depolymerization, suggesting more mineralization due to increases in fungal: bacterial ratio or in the availability of substrates. Understanding plant-soil feedback in crop rotation systems is crucial to improve our practices and sustainably meet crops nutritional needs. O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=122 SRC="FIGDIR/small/694934v2_ufig1.gif" ALT="Figure 1"> View larger version (37K): org.highwire.dtl.DTLVardef@129f684org.highwire.dtl.DTLVardef@1f78d20org.highwire.dtl.DTLVardef@152466dorg.highwire.dtl.DTLVardef@8da2e2_HPS_FORMAT_FIGEXP M_FIG C_FIG HighlightsO_LIPrevious crop identity distinctively shaped wheat rhizosphere microbial communities C_LIO_LIPrevious legume did not altered the enzymatic activity of wheat-associated rhizosphere microbes, but increased soil ammonium C_LIO_LIWheat grain protein content was higher following faba bean than peas C_LI

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L'Esperance, E., Poirier, V., Lavergne, S., Yergeau, E.. 2025-12-17. Previous legume identity influences wheat protein content through organic matter depolymerization. https://doi.org/10.64898/2025.12.17.694934

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