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

Abstract

Fusarium equiseti is prevalent in ginseng soil, straw mulch and in ginseng root tissues and is the cause of a root surface discolouration on ginseng grown in British Columbia. Population levels of the fungus in ginseng fields ranged from 3.8×10 3 cfu g −1 soil to 1.4×10 4 cfu g −1 soil and were highest at 0-5 cm soil depths compared to 10-15 cm. Soil population levels were negatively correlated with S content in soil and positively correlated with Zn levels. Barley or wheat straw added to soil significantly increased population levels under laboratory conditions. Mycelial growth in culture was highest at 26-30°C and at pH 7.2-7.8. Samples of flowers and berries, and harvested seed, contained DNA of F. equiseti detected using a Fusarium-specific DNA array and the fungus was isolated from these tissues on agar medium. A high degree of genetic variation in the EF-1 alpha gene sequence was present among 52 isolates of F. equiseti which originated from ginseng fields. At least seven clades were identified. Inoculum dispersal from straw mulch used in ginseng gardens can result in seed contamination by the fungus. In addition, fungal growth near the soil surface under warm summer conditions can result in infection and crown discolouration of ginseng roots.

Mycotoxins Biosynthesized by Plant-Derived Fusarium Isolates / Tvorba Mikotoksina U Vrstama Roda Fusarium Izoliranim Iz Biljaka

“…It was also possible to detect some intraspecific polymorphism among F. proliferatum isolates, as it has been already postulated previously (11). Similarly, it was described that the genotypes belonging to two or more isolated populations of the same species can be distinguished from each other on the basis of tef-1α gene analysis (8,12). It is possible that such a high level of polymorphism among genotypes is not unusual and could also have been found elsewhere, e.g.…”

“…Molecular identifi cation of fungal pathogens has been successfully used as a complementary method to morphological identifi cation using optical microscope (6,44). Among many others, the translation elongation factor 1α (tef-1α) has been proven to be so far the most versatile and useful phylogenetic marker (8,10,59). The BLASTn analysis of this divergent region of 34 isolates studied helped to identify ten Fusarium species (results not shown).…”

“…However, there is little information on secondary metabolites produced by Fusaria infecting crop plants other than cereals (7)(8)(9)(10)(11)(12). Due to systemic dispersal inside the host plant, many members of the Fusarium genus have the ability to colonise perennial crops with only scarce infection or disease symptoms or with no symptoms at all while still being detectable (11,13).…”

Efectos del quitosano en hongos fitopátogenos y en la germinación de semillas de Jatropha curcas L.

“…The pathogenicity of F. equiseti has been reported in previous studies on Pinus ponderosa Douglas ex C. Lawson seeds, and it has been demonstrated to cause damping-off and root rot on seedlings (Salerno & Lori, 2007). Additionally, F. equiseti is prevalent in ginseng (Panax quinquefolius L.) soil causing the discoloration of the root surface (Punja et al, 2008). In a recent study, F. equiseti obtained from seeds caused foliar necrosis and wilt on pecan (Carya illinoinensis [Wangenh.]…”

“…La patogenicidad de F. equiseti ha sido reportada en estudios previos sobre semillas de Pinus ponderosa Douglas ex C. Lawson y se ha demostrado que causa caída de almácigos y pudrición de raíz en plántulas (Salerno & Lori, 2007). Además, F. equiseti es frecuente en suelo de ginseng (Panax quinquefolius L.), provocando la decoloración de la superficie de la raíz (Punja et al, 2008). En un estudio reciente, F. equiseti, obtenido a partir de semillas, causó necrosis foliar y marchitamiento en pacana (Carya illinoinensis [Wangenh.]…”