Pathogenicity, Mycotoxin Production, and Control of Potato Dry Rot Caused by Fusarium spp.: A Review

Fusarium spp.: infections and intoxications

The genus Fusarium, member of the Hypocreaceae family, comprises over 500 spp. with an ever-evolving taxonomy. These fungi, some highly pathogenic, primarily affect various plants, including major crops like maize, rice, cereals, and potatoes, leading to significant agricultural losses and contributing to human undernutrition in certain regions. Additionally, Fusarium spp. produce harmful mycotoxins like trichothecenes, fumonisins, zearalenones, etc., posing health risks to animals and humans. These toxins generally transferred to food items can cause diverse issues, including organ failure, cancer, and hormonal disturbances, with effects sometimes appearing years after exposure. The fungi's vast genetic repertoire enables them to produce a range of virulence factors, leading to infections in both animals and humans, particularly in immunocompromised individuals. Fusarium spp. can cause systemic infections and local infections like keratitis. Due to limited antifungal effectiveness and biofilm formation, these infections are often challenging to treat with poor outcomes.

Mycotoxin Accumulation in Dry Rot Potato Tubers from Algeria and Toxigenic Potential of Associated Isolates of Fusarium Genus

The presence of different mycotoxins in 232 tuber samples exhibiting dry rot symptoms and their associated Fusarium strains from two production sites in Algeria was investigated. LC-MS/MS was used to simultaneously detect and quantify 14 mycotoxins, including trichothecenes and non-trichothecenes. A total of 49 tubers were contaminated with at least one mycotoxins, including T-2, HT-2, Diacetoxyscirpenol (DAS), 15-acetoxyscirpenol (15-AS) and Beauvericin (BEA). Positive samples from the Bouira region had a significantly higher level of toxin contamination compared to Ain Defla (56.34% and 5.59%, respectively). A total of 283 Fusarium strains were isolated: 155 from Bouira and 128 from Ain Defla. These strains were evaluated for their ability to produce the targeted mycotoxins. The results showed that 61.29% and 53.9% of strains originate from Bouira and Ain Defla regions were able to produce Nivalenol, Fusarenone-X, DAS, 15-AS, Neosolaniol, BEA and Zearalenone. The phylogenetic analysis of the conserved ribosomal internal transcribed spacer (ITS) sequences of 29 Fusarium strains, representative of the recorded mycotoxins profiles, was distributed into 5 Fusarium species complexes (SC): F. incarnatum-equiseti SC (FIESC), F. sambucinum SC (FSAMSC), F. oxysporum SC (FOSC), F. tricinctum SC (FTSC) and F. redolens SC (FRSC). This is the first study determining multiple occurrences of mycotoxins contamination associated to Fusarium dry rot of potato in Algeria and highlights fungal potential for producing trichothecene and non-trichothecens mycotoxins.

Characterization of three novel stem rot pathogens and their antagonistic endophytic bacteria associated with Cistanche deserticola

Cistanche deserticola is a precious Chinese medicinal material with extremely high health care and medicinal value. In recent years, the frequent occurrence of stem rot has led to reduced or even no harvests of C. deserticola. The unstandardized use of farm chemicals in the prevention and control processes has resulted in excessive chemical residues, threatening the fragile desert ecological environment. Therefore, it is urgent to explore safe and efficient prevention and control technologies. Biocontrol agents, with the advantages of safety and environment-friendliness, would be an important idea. The isolation, screening and identification of pathogens and antagonistic endophytic bacteria are always the primary basis. In this study, three novel pathogens causing C. deserticola stem rot were isolated, identified and pathogenicity tested, namely Fusarium solani CPF1, F. proliferatum CPF2, and F. oxysporum CPF3. For the first time, the endophytic bacteria in C. deserticola were isolated and identified, of which 37 strains were obtained. Through dual culture assay, evaluation experiment and tissue culture verification, a biocontrol candidate strain Bacillus atrophaeus CE6 with outstanding control effect on the stem rot was screened out. In the tissue culture system, CE6 showed excellent control effect against F. solani and F. oxysporum, with the control efficacies reaching 97.2% and 95.8%, respectively, indicating its great potential for application in the production. This study is of great significance for the biocontrol of plant stem rot and improvement of the yield and quality of C. deserticola.