Work

Perennialization and intercropping effects on cereal rhizosphere microbiome

Year: 2025

Type: article

Abstract: Perennial agriculture is an alternative agricultural paradigm with potential to improve soil health and reduce energy input. Cereal-legume intercropping (or biculture) is often suggested together with perennial crops as a way to reduce exogenous nitrogen (N) input. In developing new perennial cereal varieties, a crop’s ability to adapt to neighboring legumes and optimize interactions between crops is of particular interest. The rhizosphere microbial community plays a major part in this plant adaptation since much of the N transfer between cereals and legumes is facilitated by microbial activity. Therefore, we conducted a field study to examine plant performance and rhizosphere communities of the recently domesticated perennial cereal Kernza (Thinopyrum intermedium (Host) Barkworth & D.R.Dewey), annual wheat (Triticum turgidum L. subsp. durum (Desf.) Husn.), and their hybrid, perennial wheat in monoculture or in biculture with alfalfa (Medicago sativa L.). We profiled rhizosphere microbial communities over two growing seasons using 16S rRNA and ITS gene amplicon sequencing. We hypothesized that: 1) rhizosphere microbial community composition of annual wheat and Kernza will be most dissimilar from each other with perennial wheat (the hybrid) being intermediate, and 2) all microbial communities will shift in biculture, with the greatest change in Kernza and the smallest in annual wheat. We found that the bacterial membership from Kernza soils differed significantly from the other two genotypes. Profiled communities did not differ between perennial and annual wheat; the hybrid seemingly inherited microbial recruitment traits of its annual parent more so than from Kernza. Interestingly, the inclusion of alfalfa led to the convergence of 16S rRNA gene amplicon profiles, likely due to its competitive pressure across genotypes. In contrast, the fungal community did not show a clear genotype effect. In conclusion, we found that crop genotype influenced rhizosphere microbial communities, and that this was further shaped by legume competition, with rhizosphere microbiome inheritability skewed toward the annual parent. Our study demonstrates the importance of including rhizosphere plant genotype-microbial interactions in the evaluation of novel cereal crops in both monoculture and cereal-legume biculture.

Source: Applied Soil Ecology

DOI: 10.1016/j.apsoil.2025.106757