Antagonistic Bacillus species as a biological control of ginseng root rot caused by Fusarium cf. incarnatum

Abstract

BackgroundThis study aimed to develop a biocontrol system for ginseng root rot caused by Fusarium cf. incarnatum.MethodsIn total, 392 bacteria isolated from ginseng roots and various soils were screened for their antifungal activity against the fungal pathogen, and a bacterial isolate (B2-5) was selected as a promising candidate for the biocontrol because of the strong antagonistic activity of the bacterial cell suspension and culture filtrate against pathogen.ResultsThe bacterial isolate B2-5 displayed an enhanced inhibitory activity against the pathogen mycelial growth with a temperature increase to 25°C, produced no pectinase (related to root rotting) and no critical rot symptoms at low [106 colony-forming units (CFU)/mL] and high (108 CFU/mL) inoculum concentrations. In pot experiments, pretreatment with the bacterial isolate in the presumed optimal time for disease control reduced disease severity significantly with a higher control efficacy at an inoculum concentration of 106 CFU/mL than at 108 CFU/mL. The establishment and colonization ability of the bacterial isolates on the ginseng rhizosphere appeared to be higher when both the bacterial isolate and the pathogen were coinoculated than when the bacterial isolate was inoculated alone, suggesting its target-oriented biocontrol activity against the pathogen. Scanning electron microscopy showed that the pathogen hyphae were twisted and shriveled by the bacterial treatment, which may be a symptom of direct damage by antifungal substances.ConclusionAll of these results suggest that the bacterial isolate has good potential as a microbial agent for the biocontrol of the ginseng root rot caused by F. cf. incarnatum.

Biological characteristics ofBacillus amyloliquefaciensAK-0 and suppression of ginseng root rot caused byCylindrocarpon destructans

“…The degree of rotting was scored using the disease severity rating system as follows: 0, no rot; 1, 1–10%; 2, 10–30%; 3, 30–50%; 4, 50–70%; and 5, 70–100% (or fully) rotted as described by Song et al . (). The experiment was carried out at least two times with three replicates per treatment.…”

“…Roots were examined for the development of root rot symptoms 4 and 10 days after incubation at 21°C. The degree of rotting was scored using the disease severity rating system as follows: 0, no rot; 1, 1-10%; 2, 10-30%; 3, 30-50%; 4, 50-70%; and 5, 70-100% (or fully) rotted as described by Song et al (2014).…”

Biological control in the germination of seeds from two species native of the Cerrado region

“…Members of this genus are commonly found in environments with soil and water. Some of its species have antifungal activity against plant pathogens and are capable of inhibiting mycelial growth and the germination of conidia, and thus play important roles in the infection cycle of pathogenic agents (Song et al, 2014).…”

Plant-Growth-Promoting Rhizobacteria (PGPR) and Medicinal Plants

“…Low soil P availability has profound impact on global agriculture and food production (Song et al 2014). Low solubility and precipitation of added P source is the major issue of semiarid and arid regions of the world.…”