Description of a new genus and three new species of Otothyrinae (Siluriformes,Loricariidae)

The genus Hisonotus was resurrected as a member of the tribe Otothyrini (actually subfamily Otothyrinae). However, phylogenetic studies based on morphological and molecular data showed that Hisonotus is not monophyletic and independent lineages can be identified, such as the group composed of the species Hisonotus insperatus, Hisonotus luteofrenatus, Hisonotus oliveirai, Hisonotus paresi and Hisonotus piracanjuba, a lineage unrelated to that containing the type species of the genus Hisonotus (Hisonotus notatus). Herein, based in molecular and morphological data, a new genus is described to accommodate the lineage mentioned above, into which are also added three new species. This new genus can be distinguished from other genera of Otothyrinae by the following combination of characters: (1) a pair of rostral plates at the tip of the snout; (2) two large pre-nasal plates just posterior to the rostral plates; (3) a supra-opercular plate that receives the laterosensory canal from the compound pterotic before the preopercle; (4) a well developed membrane at anal opening in females; and (5) a V-shaped spinelet. A key to species of Curculionichthys is provided.     

Response of wheat restricted‐tillering and vigorous growth traits to variables of climate change

The response of wheat to the variables of climate change includes elevated CO₂, high temperature, and drought which vary according to the levels of each variable and genotype. Independently, elevated CO₂, high temperature, and terminal drought affect wheat biomass and grain yield, but the interactive effects of these three variables are not well known. The aim of this study was to determine the effects of elevated CO₂ when combined with high temperature and terminal drought on the high‐yielding traits of restricted‐tillering and vigorous growth. It was hypothesized that elevated CO₂ alone, rather than combined with high temperature, ameliorates the effects of terminal drought on wheat biomass and grain yield. It was also hypothesized that wheat genotypes with more sink capacity (e.g. high‐tillering capacity and leaf area) have more grain yield under combined elevated CO₂, high temperature, and terminal drought. Two pairs of sister lines with contrasting tillering and vigorous growth were grown in poly‐tunnels in a four‐factor completely randomized split‐plot design with elevated CO₂ (700 µL L^?1), high day time temperature (3 °C above ambient), and drought (induced from anthesis) in all combinations to test whether elevated CO₂ ameliorates the effects of high temperature and terminal drought on biomass accumulation and grain yield. For biomass and grain yield, only main effects for climate change variables were significant. Elevated CO₂ significantly increased grain yield by 24–35% in all four lines and terminal drought significantly reduced grain yield by 16–17% in all four lines, while high temperature (3 °C above the ambient) had no significant effect. A trade‐off between yield components limited grain yield in lines with greater sink capacity (free‐tillering lines). This response suggests that any positive response to predicted changes in climate will not overcome the limitations imposed by the trade‐off in yield components.     

Differential expression of the pr1A gene in Metarhizium anisopliae and Metarhizium acridum across different culture conditions and during pathogenesis

The entomopathogenic fungi of the genus Metarhizium have several subtilisin-like proteases that are involved in pathogenesis and these have been used to investigate genes that are differentially expressed in response to different growth conditions. The identification and characterization of these proteases can provide insight into how the fungus is capable of infecting a wide variety of insects and adapt to different substrates. In addition, the pr1A gene has been used for the genetic improvement of strains used in pest control. In this study we used quantitative RT-PCR to assess the relative expression levels of the pr1A gene in M. anisopliae and M. acridum during growth in different culture conditions and during infection of the sugar cane borer, Diatraea saccharalis Fabricius. We also carried out a pathogenicity test to assess the virulence of both species against D. saccharalis and correlated the results with the pattern of pr1A gene expression. This analysis revealed that, in both species, the pr1A gene was differentially expressed under the growth conditions studied and during the pathogenic process. M. anisopliae showed higher expression of pr1A in all conditions examined, when compared to M. acridum. Furthermore, M. anisopliae showed a greater potential to control D. saccharalis. Taken together, our results suggest that these species have developed different strategies to adapt to different growing conditions.     

Identification and characterization of expressed retrotransposons in the genome of the Paracoccidioides species complex

Background

Species from the Paracoccidioides complex are thermally dimorphic fungi and the causative agents of paracoccidioidomycosis, a deep fungal infection that is the most prevalent systemic mycosis in Latin America and represents the most important cause of death in immunocompetent individuals with systemic mycosis in Brazil. We previously described the identification of eight new families of DNA transposons in Paracoccidioides genomes. In this work, we aimed to identify potentially active retrotransposons in Paracoccidioides genomes.

Results

We identified five different retrotransposon families (four LTR-like and one LINE-like element) in the genomes of three Paracoccidioides isolates. Retrotransposons were present in all of the genomes analyzed. P. brasiliensis and P. lutzii species harbored the same retrotransposon lineages but differed in their copy numbers. In the Pb01, Pb03 and Pb18 genomes, the number of LTR retrotransposons was higher than the number of LINE-like elements, and the LINE-like element RtPc5 was transcribed in Paracoccidioides lutzii (Pb01) but could not be detected in P. brasiliensis (Pb03 and Pb18) by semi-quantitative RT-PCR.

Conclusion

Five new potentially active retrotransposons have been identified in the genomic assemblies of the Paracoccidioides species complex using a combined computational and experimental approach. The distribution across the two known species, P. brasiliensis and P. lutzii, and phylogenetics analysis indicate that these elements could have been acquired before speciation occurred. The presence of active retrotransposons in the genome may have implications regarding the evolution and genetic diversification of the Paracoccidioides genus.

Electronic supplementary material

The online version of this article (doi:10.1186/s12864-015-1564-7) contains supplementary material, which is available to authorized users.     

Mesoionic compounds with antifungal activity against Fusarium verticillioides

Background

Fungi contaminate the food of humans and animals, are a risk to health, and can cause financial losses. In this work, the antifungal activities of 16 mesoionic compounds (MI 1–16) were evaluated against mycotoxigenic fungi, including Aspergillus spp., Fusarium verticillioides and Penicillium citrinum. Furthermore, the decreased ergosterol in the total lipid content of Fusarium verticillioides was investigated.

Results

F. verticillioides was the most sensitive fungus to the mesoionic compounds. Among the evaluated compounds, MI-11 and MI-16 presented higher antifungal effects against F. verticillioides, with MIC values of 7.8 μg/ml, and MI-2 and MI-3 followed, with MICs of 15.6 μg/ml. The most active compounds were those with heterocyclic ring phenyl groups substituted by electron donor moieties (MI-11 and MI-16). Among some compounds with higher activity (MI-2, MI-11 and MI-16), decreased ergosterol content in the total lipid fraction of F. verticillioides was demonstrated. MI-2 reduced the ergosterol content approximately 40% and 80% at concentrations of 7.8 μg/ml and 15.6 μg/ml, respectively, and MI-11 and MI-16 decreased the content by 30% and 50%, respectively, when at a concentration of 7.8 μg/ml.

Conclusion

These findings indicate that mesoionic compounds have significant antifungal activity against F. verticillioides.