Forward genetic screens are efficient tools for the dissection of complex biological processes, such as fungal pathogenicity. A transposon tagging system was developed in the vascular wilt fungus Fusarium oxysporum f. sp. lycopersici by inserting the novel modified impala element imp160::gfp upstream of the Aspergillus nidulans niaD gene, followed by transactivation with a constitutively expressed transposase. A collection of 2072 Nia(+) revertants was obtained from reporter strain T12 and screened for alterations in virulence, using a rapid assay for invasive growth on apple slices. Seven strains exhibited reduced virulence on both apple slices and intact tomato plants. Five of these were true revertants showing the re-insertion of imp160::gfp within or upstream of predicted coding regions, whereas the other two showed either excision without re-insertion or no excision. Linkage between imp160::gfp insertion and virulence phenotype was determined in four transposon-tagged loci using targeted deletion in the wild-type strain. Knockout mutants in one of the genes, FOXG_00016, displayed significantly reduced virulence, and complementation of the original revertant with the wild-type FOXG_00016 allele fully restored virulence. FOXG_00016 has homology to the velvet gene family of A. nidulans. The high rate of untagged virulence mutations in the T12 reporter strain appears to be associated with increased genetic instability, possibly as a result of the transactivation of endogenous transposable elements by the constitutively expressed transposase.

Grey mold caused by Botrytis cinerea, is known to cause great losses in most vegetable and fruit crops. Fifty-one isolates of B. cinerea were collected from grape (BCG) and strawberry (BCS) grown in different Egyptian locations. Variation among isolates was demonstrated using fenhexamid resistance and genetic approaches. Isolates were classified into various pathogenic groups depending on their reactions towards lettuce leaves. Genetic variability was identified in all isolates using transposable elements (TEs) analysis which revealed either the presence or absence of boty and flipper transposons. Furthermore, TEs typing of B. cinerea isolates demonstrated four TE types, on the basis of TE distribution in B. cinerea populations, namely, transposa (having both boty and flipper), flipper (possessing only flipper), boty (having only boty), and vacuma (lacking both boty and flipper elements). Transposa type was predominant (43.1%) and both transposa and vacuma isolate types showed no specialization with respect to host plant or plant location, while flipper type revealed a geographical preference in (BCG) isolates. Pathogenicity was also correlated to TE type as isolates containing transposa type revealed some degree of correlation with virulence behaviour, suggesting that transposa populations have higher pathogenic potential as compared to vacuma ones. The sensitivity of sampled isolates was tested against fenhexamid as one of the most important botryticides. Sensitivity to fenhexamid was shown in all isolates from strawberry and grape, grown in different locations, with low EC50 values between 0.012-0.084 μg/ml. This finding provided a cue for effective usage of fenhexamid for grey mold management. The present work demonstrated a correlation between the distribution of TEs and some fungal features such as isolate source and virulence, but no correlation was found between morphological characteristics, TE type, and sensitivity to fenhexamid. Cluster analysis based on phylogenetic tree showed that the Egyptian isolates branched as a separate divergent group from the others retrieved from GenBank, reflecting the presence of sequence polymorphism between the current isolates of B. cinerea and those previously identified.

Gray mold causes considerable economic losses of fruit and vegetable production. The current study on Egyptian population structure of Botrytis cinerea demonstrates that this species is composed of four TE genotypes: transposa, vacuma, boty and flipper types using transposable elements and sensitivity to the hydroxyanilide fungicide, fenhexamid. The results show that transposa is the predominant isolate type (63.6%) in the sampled populations of B. cinerea. However, the four isolate types are fenhexamid-sensitive regardless of location, host plant and plant organ. Additionally, B. cinerea isolates collected from different host plants do not exhibit any host preference using artificial infection test on lettuce. Furthermore, no relation is found between isolate type and aggressiveness and no divergence event has occurred among the isolates collected from different locations and host plants. The results suggest that host specialization of B. cinerea has not been occurred in the current sampled crops.

Of the 4 procedures, BIL had the least deleterious effect on reproductive performance; SWUD increased the risk of premature ovarian failure, and B-Lynch increased the risks of endometriosis, intrauterine adhesions, placenta previa, and preterm labor.