Fungal diversity associated with pulses and its influence on the subsequent wheat crop in the Canadian prairies

Citation

Borrell, A.N., Shi, Y., Gan, Y., Bainard, L.D., Germida, J.J., Hamel, C. (2017). Fungal diversity associated with pulses and its influence on the subsequent wheat crop in the Canadian prairies, 414(1-2), 13-31. http://dx.doi.org/10.1007/s11104-016-3075-y

Plain language summary

Root-associated fungal communities are an important contributor to the ‘crop rotation benefit’ on soil productivity. In this study, we aimed to determine how the inclusion of pulse crops (chickpea, lentil, and pea) in wheat-based rotations affect the diversity and composition of root-associated fungal communities, and the legacy effect of pulses on a following wheat crop. DNA sequencing technology was used to describe the fungal communities of crop roots and rhizosphere soil (soil tightly bound to crop roots) in a field trial in southwestern Saskatchewan. The inclusion of pulse crops influenced the composition of the root-associated fungal community. We found that certain fungal species (Mortierella, Cryptococcus, and Paraglomus species) in the wheat rhizosphere were found to have a positive relationship with crop yield, while others (Fusarium, Davidiella, Lachnum, Sistotrema, and Podospora) had a negative relationship with crop yield. Overall, the effect of pulse crops on root fungal communities varied with crop species. This study highlighted the effect that pulse crops can have on the fungal community and their subsequent impact on crops that follow in the rotation.

Abstract

Background and aims: Variations in root-associated fungal communities contribute to the so-called ‘crop rotation benefit’ on soil productivity. We assessed the effects of chickpea, lentil, and pea in wheat-based rotations, as compared to wheat monoculture, on the structure of root-associated fungal communities, and described the legacy of pulses on a following wheat crop. Methods: The internal transcribed spacer (ITS) and 18S rRNA gene markers, and 454 amplicon pyrosequencing were used to describe the fungal communities of crop roots and rhizosphere soil in a field experiment and agronomic data were collected. Results: Pulses influenced only the structure of the non-mycorrhizal fungal community of roots. Fusarium tricinctum, Clonostachys rosea, Fusarium redolens, and Cryptococcus sp. were specific to certain crops. Despite the absence of selective effects of pulses on their associated arbuscular mycorrhizal (AM) fungal community, pea had a legacy effect on the structure of the AM fungal community associated with the roots of the following wheat crop, in one of the two year/sites examined. Species of Mortierella, Cryptococcus, and Paraglomus in wheat rhizosphere soil may benefit yield, whereas species of Fusarium, Davidiella, Lachnum, Sistotrema and Podospora may reduce yield. Conclusion: The effect of pulse crops on root fungal communities varied with rotation crop species. Pulses had various effects on the physiology of the following wheat crop, including increased productivity.