Trade-off between potential phytopathogenic and non-phytopathogenic fungi in the peanut monoculture cultivation system

Abstract

Phytopathogenic fungi are a major cause of plant disease. However, the interrelationships between phytopathogenic and non-phytopathogenic fungi in the peanut (Arachis hypogaea) monoculture system remain unclear. In this study, rhizosphere soils from four fields that had been monocropped with peanut for different durations were investigated, including monoculture for 1 year (CK), 4 years (P4), 10 years (P10), and 20 years (P20). Illumina sequencing of fungal ITS regions and FUNGuild were used to investigate the interrelationships between potential phytopathogenic and non-phytopathogenic fungi. Our results showed that the relative abundance of potential phytopathogenic fungi was significantly negatively correlated with that of non-phytopathogenic fungi (r = −0.650, P = 0.022); and the relative abundance of the key potential phytopathogenic species, Fusarium, was also significantly negatively correlated with that of the non-phytopathogenic fungi, Penicillium (r = −0.815, P = 0.001). The greater negativity between potential phytopathogenic and non-phytopathogenic fungi in the co-occurrence network implied an antagonism between them; and the greater negativity between Penicillium species and Fusarium species in the network combining with the results of confrontation experiment suggested the suppression of Penicillium species on Fusarium species. In conclusion, there is a trade-off between potential phytopathogenic and non-phytopathogenic fungi in the peanut monoculture system. Our results provide better insight towards understanding the obstacles of continuous peanut cropping.