Diversity ofFusariumspecies associated with discolored ginseng roots in British Columbia

Abstract

Crown discoloration on roots of American ginseng (Panax quinquefolius) is a major problem that causes a reduction in quality and can be a limiting factor to ginseng production in some regions of Canada. The symptoms result from an accumulation of phenolic compounds within disorganized and disrupted cells, accompanied by the presence of fungal hyphae in affected cells. Twelve Fusarium species were recovered on isolation media during JuneSeptember of 2004 and 2005 from ginseng roots displaying root-surface discoloration in British Columbia. Many of the same species were also recovered from soil from ginseng fields and cereal-straw mulch used during ginseng production. Hybridization of labeled PCR amplicons from DNA samples from affected root tissue to a DNA array designed using oligonucleotides specific to 26 Fusarium species was used to identify the Fusarium species present in ginseng roots.

Growth, population dynamics, and diversity of Fusarium equiseti in ginseng fields

“…A 1 cm 3 soil sample was diluted to 10 −2 and 0.5 ml was plated onto each of four replicate dishes and incubated at 21-23°C for 7-10 days. Colonies of F. equiseti appeared whitish-pink on this medium (Punja et al 2008). Colony counts were converted to cfu g −1 of soil after determining the moisture content in each sample.…”

“…seed decay and damping-off on ginseng seedlings (Brammall 1994;Punja 1997). In addition, F. equiseti and F. sporotrichioides were reported to cause a superficial root surface discolouration on ginseng roots (Punja et al 2008) that significantly reduces marketability. Fusarium equiseti was the most frequently recovered species of Fusarium from straw mulch used during ginseng production and from ginseng soil, and was the most pathogenic species to ginseng roots (Punja 1997).…”

“…In the light of the prevalence of F. equiseti in ginseng fields in British Columbia and its role in causing a root surface discolouration symptom (Punja et al 2008), and the lack of information on factors influencing growth of F. equiseti, a better understanding of the epidemiology of this pathogen was needed. The objectives of this research were to: (1) study factors affecting growth of F. equiseti, specifically temperature, pH, fungicides and plant residues; and (2) determine the population dynamics and extent of genetic diversity among isolates originating from ginseng fields.…”

Primer registro de Fusarium solani y F. equiseti en plantaciones de Jatropha curcas en México

“…Existen otros reportes de F. equiseti pero como agente causal de "damping-off ", pudrición de raíz y marchitez en Pinus halepensis, H. sabdariffa y Panax quiquefolius (Punja et al, 2007;Hasan et al, 2014;Lazreg et al, 2014), así como inductor de necrosis floral y caída de frutos jóvenes en Carica papaya (Vásquez et al, 2012). Sin embargo, este es el primer reporte de muerte descendente y acortamiento de entrenudos en tallos de J. curcas.…”

“…La secuencia de nucleótidos, se depositó In plants of J. curcas with symptoms of dieback and stems with shortened internodes, Fusarium equiseti was isolated and identified ( Figure 2A, B, D and E). There are other reports of F. equiseti but as causal agent of damping-off, root rot and wilting in Pinus halepensis, H. sabdariffa and Panax quiquefolius (Punja et al, 2007;Hasan et al, 2014;Lazreg et al, 2014), as well as inducer of floral necrosis and young fruit falling in Carica papaya (Vásquez et al, 2012). However, this is the first report of dieback and internodes shortening in stems of J. curcas.…”