Available online 6 December 2023

P-hydroxybenzoic acid have negative effect on soil environment.

The p-hydroxybenzoic acid induce lead to aggravate root rot disease.

P-hydroxybenzoic acid can significantly increase density of F. oxysporum.

P-hydroxybenzoic acid have negative effect on the root systems.

Plant health is directly related to the change in native microbial diversity and changes in soil health have been implicated as one of the main cause of root rot. However, scarce information is present to investigate allelopathic relationship of Panax notoginseng root exudates and pathogenic fungi Fusarium oxysporum in a continuous cropping system.

We analyzed P. notoginseng root exudate in the planting soil for successive three (3) years to determine phenolic acid concentration using GC-MS and HPLC followed by effect on the microbial community assembly. Antioxidant enzymes were checked in the roots to confirm possible resistance in P. notoginseng.

Total 29 allelochemicals in the planting soil extract was found with highest concentration (10.54 %) of p-hydroxybenzoic acid. The HPLC showing a year-by-year decrease in p-hydroxybenzoic acid content in soil of different planting years, and an increase in population dynamic of F. oxysporum. Moreover, community analysis displayed negative correlation with 2.22 mmol. L−1 of p-hydroxybenzoic acid correspond to an 18.1 % population of F. oxysporum. Furthermore, in vitro plate assay indicates that medium p-hydroxybenzoic acid (2.5–5 mmol. L−1) can stimulate the growth of F. oxysporum colonies and the production of macroconidia, as well as cell wall-degrading enzymes. We found that 2–3 mmol. L−1 of p-hydroxybenzoic acid can significantly increase the population of F. oxysporum.

In conclusion, our study suggested that p-hydroxybenzoic acid have negative effect on the root systems and modified the rhizosphere microbiome so that the host plant became more susceptible to root rot disease.

Allelochemicals

Soil-borne pathogen

Phenolic acid

Pathogenicity

© 2023 The Korean Society of Ginseng. Publishing services by Elsevier B.V.