Suppression of soil-borne Fusarium pathogens of peanut by intercropping with the medicinal herb Atractylodes lancea

Intercropping has historically been employed as an efficient management strategy to prevent disease outbreaks. Our previous studies indicated that intercropping of peanut with the Chinese medicinal herb, Atractylodes lancea effectively suppressed soil-borne peanut diseases, resulting in increased peanut yields. However, the underlying mechanism is unknown. In this study, the below ground effects of A. lancea on both fungal and bacterial communities in the peanut rhizosphere were investigated using pyrosequencing of the internal transcribed spacer (ITS1) and16S rRNA gene amplicons, respectively. Closed cultivation systems were constructed to investigate the role of volatiles and exudates originating from rhizomes and roots of A. lancea on fungal and bacterial communities. Intercropping with A. lancea significantly altered fungal community composition in the peanut rhizosphere, coinciding with decline of Fusarium root rot and improvement of peanut growth. Volatiles originating from A. lancea rhizome material had more effects on fungal communities than on bacterial communities, and significantly suppressed F. oxysporum growth. Root exudates of A. lancea had no apparent inhibitory effect on F. oxysporum. Gas chromatography–mass spectrometry (GC-MS) analysis revealed 21 volatiles originating from A. lancea rhizome material and terpenes and aromatic hydrocarbons were the most common types. Our results suggest that A. lancea suppressed pathogenic Fusarium populations by means of volatiles from the rhizome. Our results support the idea that intercropping with A. lancea or use of its effective components has a strong potential for managing soil-borne fungal diseases.