Genetic Variability of Phytopathogenic Fusarium proliferatum Associated with Crown Rot in Asparagus officinalis

Abstract

Fusarium proliferatum (teleomorph: Gibberella intermedia) is a causal agent of crown rot of Asparagus officinalis and is one potential fumonisin-producing species within the genus Fusarium. It colonizes roots and crowns of asparagus plants, but could also be isolated from symptomless asparagus spears. Fusarium proliferatum isolates obtained from perennial asparagus plantings from Austria and Germany were included in a study on detectability and variability of two essential genes of the fumonisin-gene cluster. Genetic fingerprinting of 45 isolates revealed 14 different fingerprint groups, indicating genetic heterogenicity of F. proliferatum. Most isolates differentiated into three main fingerprint clusters, but no association was found between fingerprint group and origin of the isolates. By gene-specific PCR it was shown that, in 25 isolates tested, both initial genes of the fumonisin biosynthetic pathway -FUM1, encoding a polyketide synthase and FUM8, a gene for a putative aminoacyl transferase -were detectable. This suggests that these isolates were able to produce fumonisins and could contribute to the detected contamination in originating asparagus spears with this mycotoxin. Thus, early detection of FUM-genes in F. proliferatum-colonized asparagus may be suited to prevent uptake of fumonisin contaminated food with the human diet. Restriction fragment length polymorphism analysis (PCR-RFLP) of the amplified FUM gene fragments revealed little sequence variability, suggesting a conserved structure of these genes within this species. However, sequence analysis confirmed intraspecific nucleotide polymorphisms of these genes.

Host extract modulates metabolism and fumonisin biosynthesis by the plant-pathogenic fungus Fusarium proliferatum

“…When consumed by animals, they can lead to liver cancer, pulmonary edema and equine leukoencephalomalacia, and in human FBs has been correlated to high incidence of esophaegal cancer in South Africa (Desjardins, 2006). The highest levels of naturally occurring fumonisins (synthesized by F. proliferatum) were recorded in maize kernels (30 mg/kg of FB 1 and 15 mg/kg of FB 2 ), and, in lower amounts in other plant tissues, such as asparagus spears (von Bargen et al, 2009), pea seeds , pineapple fruit and garlic bulbs (Stankovic et al, 2007). In laboratory conditions, however, strains isolated from asparagus, garlic and pineapple yielded more fumonisins than strains of maize origin (Stępień et al, 2011b).…”

“…It is known to be the main cause of maize cob fusariosis (along with Fusarium verticillioides), but can also colonize wheat, barley, rice, asparagus, garlic, pea, onion, tomato, pineapple, fig and various palms (Jurado et al, 2010;Kerényi et al, 2002;Stępień et al, 2011b;von Bargen et al, 2009;Waśkiewicz et al, 2013). Moreover, it has been isolated from uncultivated plants including reed, sorrel, prairie grasses and pine (Bhale et al, 2012).…”

Diversity of Pea-Associated F. proliferatum and F. verticillioides Populations Revealed by FUM1 Sequence Analysis and Fumonisin Biosynthesis

“…However, rice and sorghum are also often infected with Fusaria belonging to the Gibberella fujikuroi species complex: F. fujikuroi , F. proliferatum , F. verticillioides and F. andiyazi [20,21]. Several reports describing the contamination of crop plants with fumonisin-producing Fusarium species included wheat [22,23], garlic [24,25,26,27], asparagus [26,28,29,30,31], pineapple [26,32] and soybean [33]. …”

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

“…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).…”