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Environmental conditions in Sardinia (Tyrrhenian Islands) are conducive to fusarium root rot (FRR) and fusarium head blight (FHB). A monitoring survey on wheat was carried out from 2001 to 2013, investigating relations among these diseases and their causal agents. FHB was more frequently encountered in the most recent years while FRR was constantly present throughout the monitored period. By assessing the population composition of the causal agents as well as their genetic chemotypes and EF-1a polymorphisms, the study examined whether the two diseases could be differentially associated to a species or a population. Fusarium culmorum chemotypes caused both diseases and were detected at different abundances (88% 3-ADON, 12% NIV). Fusarium graminearum (15-ADON genetic chemotype) appeared only recently (2013) and in few areas as the causal agent of FHB. In F. culmorum, two haplotypes were identified based on an SNP mutation located 34 bp after the first exon of the EF-1a partial sequence (60% adenine, 40% thymine); the two populations did not segregate with the chemotype but the A-haplotype was significantly associated with FRR in the Sardinian data set (P = 0Á001), suggesting a possible fitness advantage of the A-haplotype in the establishment of FRR that was neither dependent on the sampling location nor the sampling year. The SNP determining the Sardinian haplotype is distributed worldwide. The question whether the A-haplotype segregates with characters facilitating FRR establishment will require further validation on a specifically sampled international data set.

Random amplification of polymorphic DNA (RAPD-PCR) analysis was conducted on 48 isolates of Fusarium oxysporum f. sp. radicis-lycopersici (F.o.r.l.) from different geographic regions, representing all known vegetative compatibility groups (

High-throughput methods are needed for functional genomics analysis in Fusarium culmorum, the cause of crown and foot rot on wheat and a type B trichothecene producer. Our aim was to develop and test the efficacy of a double-component system based on the ability of the impala transposase to transactivate the miniature inverted-repeat transposable element mimp1 of Fusarium oxysporum. We report, for the first time, the application of a tagging system based on a heterologous transposon and of splinkerette-polymerase chain reaction to identify mimp1 flanking regions in the filamentous fungus F. culmorum. Similar to previous observations in Fusarium graminearum, mimp1 transposes in F. culmorum by a cut-and-paste mechanism into TA dinucleotides, which are duplicated on insertion. mimp1 was reinserted in open reading frames in 16.4% (i.e. 10 of 61) of the strains analysed, probably spanning throughout the entire genome of F. culmorum. The effectiveness of the mimp1/impala double-component system for gene tagging in F. culmorum was confirmed phenotypically for a putative aurofusarin gene. This system also allowed the identification of two genes putatively involved in oxidative stress-coping capabilities in F. culmorum, as well as a sequence specific to this fungus, thus suggesting the valuable exploratory role of this tool.

Fusarium nygamai Burgess & Trimboli was first described in 1986 in Australia (1) and subsequently reported in Africa, China, Malaysia, Thailand, Puerto Rico, and the United States. F. nygamai has been reported on sorghum, millet, bean, cotton, and in soil where it exists as a colonizer of living plants or plant debris. F. nygamai was also reported as a pathogen of the witch-weed Striga hermonthica (Del.) Benth. To our knowledge, no reports are available on its pathogenicity on crops of economic importance. In a survey of species of Fusarium causing seedling blight and foot rot of rice (Oryza sativa L.) carried out in Sardinia (Oristano, S. Lucia), F. nygamai was isolated in association with other Fusarium species—F. moniliforme, F. proliferatum, F. oxysporum, F. solani, F. compactum, and F. equiseti. Infected seedlings exhibited a reddish brown cortical discoloration, which was more intense in older plants. The identification of F. nygamai was based on monoconidial cultures grown on carnation leaf-piece agar (CLA) (2). The shape of macroconidia, the formation of microconidia in short chains and false heads, and the presence of chlamydospores were used as the criteria for identification. Two pathogenicity tests comparing one isolate of F. nygamai with one isolate of F. moniliforme were conducted on rice cv. Arborio sown in artificially infested soil in a greenhouse at 22 to 25°C. The inoculum was prepared by growing both Fusarium species in cornmeal sand (1:30 wt/wt) at 25°C for 3 weeks. This inoculum was added to soil at 20 g per 500 ml of soil. Pre- and post-emergence damping-off was assessed. Both F. nygamai and F. moniliforme reduced the emergence of seedlings (33 to 59% and 25 to 50%, respectively, compared to uninoculated control). After 25 days, the seedlings in infested soil exhibited a browning of the basal leaf sheaths, which progressed to a leaf and stem necrosis. Foot rot symptoms caused by F. nygamai and F. moniliforme were similar, but seedlings infected by F. nygamai exhibited a more intense browning on the stem base and a significant reduction of plant height at the end of the experiment. Either F. nygamai or F. moniliforme were consistently isolated from symptomatic tissue from the respective treatments. References: (1) L. W. Burgess and D. Trimboli. Mycologia 78:223,1986. (2) N. L. Fisher et al. Phytopathology 72:151,1982.

Bakanae disease, caused by the fungal phytopathogen Fusarium fujikuroi, can be detected in most rice (Oryza sativa L.) growing areas worldwide. In this study, we investigated the population structure of this fungus in southern Lao PDR, a country located near the geographic origin of rice domestication. Microsatellites (SSRs) and mating type (MAT) analyses, pathogenicity and fungicide sensitivity tests were integrated in the study. The first key finding is that the population genetic structure of F. fujikuroi in Lao PDR is consistent with high clonal reproduction. Indeed, (i) “true” clones were identified; (ii) within populations, MAT types were frequently skewed from 1:1 ratio, (iii) linkage disequilibrium (among SSRs as also among SSRs and MAT) was present, and (iv) gene-flow between opposite MAT types within the same population is restricted. The presence of genetic divergence among areas and populations and the occurrence of positive spatial autocorrelation of genetic variation, indicate that migration is restricted, and that genetic drift plays an important role in the evolution of this fungus. Two main well-defined groups of isolates were detected (FST = 0.213) that display a non-random spatial distribution. They differ in the ability to induce seedlings death but not seedlings elongation (the typical Bakanae symptom) suggesting that the pathogen’s ability to induce the two symptoms is under different genetic control. Finally, we compared two agroecosystems with contrasting characteristics: low-input and traditional (Lao PDR) vs high-input and modern (Italy). We found differences in the level of population structuring and of spatial autocorrelation. This suggests that the evolutionary potential of the fungus not only depends on its intrinsic characteristics, but is strongly influenced by other external factors, most likely by the dynamics of infested seed exchange. Thus, quarantine and chemical treatments are a way to reduce population connectivity and hence the evolutionary potential of this pathogen.

Younger women are perceived as possessing a host of socially desirable attributes, some of which are the same traits attributed to attractive women (Perlini, Bertolissi, & Lind, 1999). Evolutionary hypotheses would not predict similar patterns of trait ascriptions for males who differ in age and attractiveness, since neither youth nor beauty is a successful strategy for mate selection amongst females. To test this hypothesis, young and elderly females rated the traits of attractiveness, social desirability, and resourcefulness in 1 of 4 target males who varied in age and attractiveness. The results indicated that neither the age nor the attractiveness of the male target influenced ascriptions of socially desirable traits. Young, compared to elderly, judges ascribed more resourcefulness to the male targets. Regardless of the target age, the younger female judges rated the target males as younger looking, in terms of estimated age, compared to the elderly female judges. The results are discussed in terms of possible sociocultural and evolutionary factors that may be responsible for these differences.