The genetic structure of 276 Sclerotinia sclerotiorum isolates representing 37 field populations from four provinces in northern Iran were analysed with six polymorphic microsatellite loci. In total, 80 haplotypes were detected with 19 haplotypes (23.7%) shared amongst at least two regional populations. None of the haplotypes were shared among all four regional populations. Of the 80 haplotypes, 32 haplotypes (40%) occurred in low frequencies represented by only one isolate. Moderate levels of gene diversity (H=0.51 to 0.61) and genotypic diversity (Ĝ=12.0 to 22.0; clonal fraction = 0.39 to 0.67) for regional populations were observed. Genotypic diversities (Ĝ) did not differ significantly among populations. All regional populations were in linkage equilibrium indicating the occurrence of outcrossing. Low to moderate levels of population subdivision (0.03 to 0.07), were observed among regional populations. Only one large panmictic population was inferred by STRUCTURE, indicating no significant population structure. A Mantel test showed no significant isolation by distance (r=−0.43; P=0.18), indicating anthropogenic movement of inoculum. The results demonstrated that S. sclerotiorum populations in northern Iran, are randomly mating and have a number of shared haplotypes among regional populations; this possibly represents recent founder populations and/or a high occurrence of anthropogenic migration of infected plant material among populations.

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Descriptions and illustrations are provided for six diatrypaceous species from Iran. Diatrypella macrospora is introduced as new to science. It differs from all other Diatrypella species by its larger ascospores. New records for the Iranian mycota include Cryptovalsa rabenhorstii, Eutypella citricola, Peroneutypa scoparia and Quaternaria quaternata. Descriptions and illustrations of microscopic characters, ITS sequence data and taxonomic notes are provided for these newly reported taxa.

Two species of Diatrypaceae (Xylariales) are described and illustrate from Iran. Diatrypella iranensis from dead branches of Quercus brantii is described as a new species based on both morphology and molecular sequence data. It differs from other members of the genus on the basis of stroma morphology and ascus and ascospore sizes. Molecular data of the ITS rDNA region show that the new species is a sister taxon of Diatrypella quercina. Cryptovalsa ampelina is described from dead branches of Juglans regia and is a new record from Iran. This study is the first in a series that investigate the diversity of Diatrypaceae from Iran.

The use of plant extracts in pre- and post-harvest disease management of agricultural crops to cope with aflatoxin B1 contamination has shown great promise due to their capability in managing toxins and safe-keeping the quality. We investigated the anti-aflatoxigenic effect of multiple doses of eight plant extracts (Heracleum persicum, Peganum harmala, Crocus sativus, Trachyspermum ammi, Rosmarinus officinalis, Anethum graveolens, Berberis vulgaris, Berberis thunbergii) on Aspergillus flavus via LC-MS and the down-regulatory effect of them on aflR, aflM and aflP genes involved in the aflatoxin B1 biosynthesis pathway using RT-qPCR analyses. Our results showed that H. persicum (4 mg/mL), P. harmala (6 mg/mL) and T. ammi (2 mg/mL) completely stopped the production of aflatoxin B1, without inducing significant changes in A. flavus growth. Furthermore, our findings showed a highly significant correlation between the gene expression and the aflatoxin B1 biosynthesis, such that certain doses of the extracts reduced or blocked the expression of the aflR, aflM and aflP and consequently reduced the synthesis of aflatoxin B1. Interestingly, compared to the regulatory gene (aflR), the down-regulation of expression in the structural genes (aflM and aflP) was more consistent and correlated with the inhibition of aflatoxin B1 production. Overall, this study reveals the anti-aflatoxigenic mechanisms of the selected plant extracts at the gene expression level and provides evidence for their use in plant and crop protection.

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