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Fusarium proliferatum is a world-wide occurring fungal pathogen affecting several crops included garlic bulbs. In Spain, this is the most frequent pathogenic fungus associated with garlic rot during storage. Moreover, F. proliferatum is an important mycotoxigenic species, producing a broad range of toxins, which may pose a risk for food safety. The aim of this study is to assess the intraspecific variability of the garlic pathogen in Spain implied by analyses of translation elongation factor (tef-1α) and FUM1 gene sequences as well as the differences in growth rates. Phylogenetic characterization has been complemented with the characterization of mating type alleles as well as the species potential as a toxin producer. Phylogenetic trees based on the sequence of the translation elongation factor and FUM1 genes from seventy nine isolates from garlic revealed a considerable intraspecific variability as well as high level of diversity in growth speed. Based on the MAT alleles amplified by PCR, F. proliferatum isolates were separated into different groups on both trees. All isolates collected from garlic in Spain proved to be fumonisin B 1 , B 2 , and B 3 producers. Quantitative analyses of fumonisins, beauvericin and moniliformin (common secondary metabolites of F. proliferatum) showed no correlation with phylogenetic analysis neither mycelial growth. This pathogen presents a high intraspecific variability within the same geographical region and host, which is necessary to be considered in the management of the disease., (Copyright © 2017 Elsevier Ltd. All rights reserved.)

Among the key diseases affecting the asparagus crop (Asparagus officinalis L.), vascular wilting of asparagus caused by Fusarium oxysporum f. sp. asparagi stands out worldwide. This disease significantly shortens the longevity of the crop and limits economic production. Traditional control measures have been largely ineffective, and chemical control methods are difficult to apply, making biological control approaches, specifically the use of Trichoderma, an economical, effective, and risk-free alternative. This study aimed to identify the main factors that affect the efficacy of biopesticides studied as Biological Control Agents (BCAs) against Fusarium wilt in asparagus and to assess the efficacy of Trichoderma-based biopesticides under greenhouse and semi-field conditions. We evaluated the response of three Trichoderma spp. (T. atroviride, T. asperellum, and T. saturnisporum) to environmental variables, such as temperature and water activity, and their antagonistic capacity against Fusarium oxysporum f. sp. asparagi. All three Trichoderma species inhibited the growth of the pathogen in vitro. A decrease in water activity led to a greater reduction in the growth rate. The efficacy of the three biological control agents decreased with higher temperatures, resulting in minimal inhibition, particularly under conditions of restricted available water in the environment. The effect of the fungal inoculum density was also analyzed at two different temperatures. A direct correlation between the amount of inoculum and the score on the Disease Severity Index (DSI) was observed. A notable reduction in DSI was evident in treatments with high inoculum density (106 conidium/mL) for all three species of Trichoderma tested at both temperatures. In greenhouse and semi-field tests, we observed less disease control than expected, although T. asperellum and T. atroviride showed lower disease severity indices and increased the dry weight of seedlings and crowns, whereas T. saturnisporum resulted in the highest disease rate and lowest dry weight. This work highlights that the efficacy of Trichoderma as BCAs is influenced by various factors, including the quantity of soil inocula, and environmental conditions. The study findings have strong implications for selecting appropriate Trichoderma species for controlling specific pathogens under specific environmental conditions. [ABSTRACT FROM AUTHOR]

Fusarium dry rot (FDR) is a postharvest disease of garlic crops causing yield losses worldwide. Fusarium proliferatum has been identified as the main species causing the disease. Symptoms begin as small brown lesions with a dehydrated appearance that can progress to cover the entire clove during the storage period. Symptoms on growing plants cause brown lesions on the basal plates and roots, and sometimes damping-off is observed. F. proliferatum is a polyphagous pathogen with a wide range of hosts. This pathogen colonizes garlic roots, remaining as a latent pathogen, and develops rot during storage. The pathogen can overwinter in the soil, infested crop residues, and weeds. The fungus can also persist on garlic cloves, acting as primary inoculum in the field and contributing to the long-distance spread. Using healthy plant material, rotating crops, burying crop residues, avoiding bulb injury during harvest and subsequent handling, and providing appropriate postharvest environmental conditions are crucial factors that greatly influence the disease severity. Choosing a suitable non-host crop to achieve truly effective rotation is sometimes difficult. Chemical control in the form of seed treatments or field spraying of the crop has a limited effect on controlling FDR. Field applications of biological control agents have shown some efficacy, but conditions to optimize their activity must be determined. Moreover, different soil management strategies to reduce soil inoculum must be also studied. [ABSTRACT FROM AUTHOR]

Asparagus Decline Syndrome (ADS) is one of the main phytosanitary problems of asparagus crop worldwide. Diseased plants and soil samples from 41 fields from three main production areas of Spain were surveyed. Eight Fusarium species belonging to seven species complexes were identified in soils: F. oxysporum, F. proliferatum, F. redolens, F. solani sensu stricto, F. equiseti, F. culmorum, F. compactum and F. acuminatum. Fusarium oxysporum was the most prevalent species. Statistical correlation (R² = 88%) was established between F. oxysporum inoculum density and the average temperature of the warmest month. A relationship was also established between three crop factors (average temperature, crop age and F. oxysporum inoculum density) and field disease indices. Significant differences were observed between the distribution of F. oxysporum propagules in white and green asparagus fields. Thirteen Fusarium species belonging to seven species complexes were identified from roots of diseased plants, being F. oxysporum the most prevalent. F. proliferatum, F. oxysporum and F. redolens showed pathogenicity to asparagus and were the main species associated to ADS. Fusarium oxysporum was the species with the highest genetic diversity displaying 14 sequence-based haplotypes with no geographic differentiation. This work contributes to understanding the Fusarium complex associated to ADS for developing accurate integrated disease management strategies. [ABSTRACT FROM AUTHOR]

Fusarium proliferatum is a globally distributed fungal pathogen that affects a range of crop hosts and is one of the main producers of mycotoxins, such as fumonisins, in foods. Specific PCR primers are commonly used for detection and identification of this pathogen. The aim of this study was to validate previously published F. proliferatum‐specific primers targeting the intergenic spacer (IGS) region and characterize intraspecific variation and homologous recombination events for isolates obtained from diseased garlic bulbs in Spain. Sixty‐nine isolates were morphologically identified as F. proliferatum, and their identity was confirmed by sequencing of the translation elongation factor; however, specific IGS primers did not result in an amplification product for nine of these isolates. Further analysis showed that this was due to polymorphism in the IGS region and six isolates were classified as IGS type I, while the remaining isolates were type II. Sequencing of the complete IGS region revealed numerous sequence polymorphisms amongst F. proliferatum isolates, and regions of recombination. Duplication and deletion events may have occurred via unequal crossing over during mitotic or meiotic recombination. These results suggest that the IGS region may be too variable as a reliable target for F. proliferatum‐specific identification. [ABSTRACT FROM AUTHOR]