Summary: During probing and blood feeding, haematophagous mosquitoes inoculate a mixture of salivary molecules into their vertebrate hosts’ skin. In addition to the anti‐haemostatic and immunomodulatory activities, mosquito saliva also triggers acute inflammatory reactions, especially in sensitized hosts. Here, we characterize the oedema and the cellular infiltrate following Aedes aegypti mosquito bites in the skin of sensitized and non‐sensitized BALB/c mice by flow cytometry. Ae. aegypti bites induced an increased oedema in the ears of both non‐sensitized and salivary gland extract‐ (SGE‐)sensitized mice, peaking at 6 hr and 24 hr after exposure, respectively. The quantification of the total cell number in the ears revealed that the cellular recruitment was more robust in SGE‐sensitized mice than in non‐sensitized mice, and the histological evaluation confirmed these findings. The immunophenotyping performed by flow cytometry revealed that mosquito bites were able to produce complex changes in cell populations present in the ears of non‐sensitized and SGE‐sensitized mice. When compared with steady‐state ears, the leucocyte populations significantly recruited to the skin after mosquito bites in non‐sensitized and sensitized mice were eosinophils, neutrophils, monocytes, inflammatory monocytes, mast cells, B‐cells and CD4⁺ T‐cells, each one with its specific kinetics. The changes in the absolute number of cells suggested two cell recruitment profiles: (i) a saliva‐dependent migration; and (ii) a migration dependent on the immune status of the host. These findings suggest that mosquito bites influence the skin microenvironment by inducing differential cell migration, which is dependent on the degree of host sensitization to salivary molecules.

Background: In tropical sugarcane crops, the fungus Fusarium verticillioides, the agent responsible for the occurrence of the red rot complex, occurs in association with the sugarcane borer Diatraea saccharalis. This fungus, in addition to being transmitted vertically, can manipulate both the insect and the plant for its own dissemination in the field. Due to the complex interaction between F. verticillioides and D. saccharalis, and the high incidence of the fungus in the intestinal region, our objective was to investigate whether F. verticillioides could alter the intestinal structure of the insect. Methods: We combined analysis of scanning electron microscopy and light microscopy to identify whether the presence of the fungus F. verticillioides, in artificial diets or in sugarcane, could lead to any alteration or regional preference in the insect’s intestinal ultrastructure over the course of its development, or its offspring development, analyzing the wall and microvillous structures of the mid-digestive system. Results: Here, we show that the fungus F. verticillioides alters the intestinal morphology of D. saccharalis, promoting an increase of up to 3.3 times in the thickness of the midgut compared to the control. We also observed that the phytopathogen colonizes the intestinal microvilli for reproduction, suggesting that this region can be considered the gateway of the fungus to the insect’s reproductive organs. In addition, the colonization of this region promoted the elongation of microvillous structures by up to 180% compared to the control, leading to an increase in the area used for colonization. We also used the fungus Colletotrichum falcatum in the tests, and it did not differ from the control in any test, showing that this interaction is specific between D. saccharalis and F. verticillioides. Conclusions: The phytopathogenic host F. verticillioides alters the intestinal morphology of the vector insect in favor of its colonization.

Mycoviruses are widely distributed among different groups of filamentous fungi. An awareness of infections caused by mycoviruses was highlighted in the 1980s and 1990s, when the impact of these agents on phenotypes of agriculturally and medically important fungi was reported. However, for entomopathogenic fungi, mycovirus research has only expanded significantly in the last 15 years. Due to the agricultural importance of these fungi, reflected in their use at the forefront of biological control strategies, recent studies have extensively described novel viruses and their effects on their hosts in terms of altered morphological, phenotypical, and ecological characteristics. To summarise the historical progress of mycovirology and recent discoveries, here we describe the state of the art in the study of mycoviruses associated with entomopathogenic fungi. We have limited the review to the occurrence of mycoviruses in fungi of the genera Beauveria, Cordyceps, Entomophthora, Metarhizium, and Trichoderma and have compiled an inventory of the viruses reported to infect these entomopathogenic genera, as well as a comprehensive review of the biological effects described with respect to infection by mycoviruses in fungi that are relevant to the biological control of insects. Finally, we have outlined possible research scenarios in the light of recent discoveries in the field of mycovirology, such as the use of mycoviruses as virulence modulating factors: the main character sought in biological pest control.

O estudo dos adubos verdes tem demonstrado grande potencial na recuperação da produtividade do solo e, dentre as diversas leguminosas usadas como adubo, destaca-se a crotalária. O objetivo do presente trabalho é descrever a morfologia floral e a fenologia reprodutiva, bem como caracterizar o processo de reprodução, a predação de frutos e a germinação de sementes de Crotalaria spectabilis Roth (Fabaceae). O estudo foi conduzido em uma área de cultivo agroecológico em Araras (SP). Indivíduos foram marcados e acompanhados para as observações fenológicas e os visitantes florais foram registrados ao longo do período do experimento, anotando-se a frequência, o horário e a duração de suas visitas. Experimentos de germinação das sementes foram conduzidos em condições naturais. Verificou-se que as flores se reúnem em racemos do tipo cacho, apresentam a formação típica das papilionáceas, com corola de cor amarela, e a porção mediana do estandarte, o qual funciona como guia de néctar, apresenta linhas marrons. A antese é diurna, caracterizada pela distensão e reflexão do estandarte, e a duração das flores é de aproximadamente, cinco dias. Quanto ao sistema de reprodução, a espécie é autocompatível, mas apresenta preferência pela polinização cruzada, sendo Xylocopa sp. polinizadora efetiva. Para o teste de germinação, utilizaram-se sementes oriundas de frutos predados e não predados, obtendo-se as porcentagens de germinação para C. spectabilis de 86,57% e 56,67%, respectivamente.

Colletotrichum falcatum is a major fungal pathogen responsible for severe disease in sugarcane. Here, we report the complete genomic characterization of a novel mycovirus infecting C. falcatum , designated Colletotrichum falcatum victorivirus 1 (CfVV1). The CfVV1 genome is 4,906 base pairs (bp) long and comprises two open reading frames encoding a capsid protein (CP) and an RNA-dependent RNA polymerase (RdRP), overlapping at an AUGA motif. The predicted proteins share ca. 70% and 68% identity with those of Colletotrichum cliviicola victorivirus 1 and Colletotrichum nativitas totivirus 1, respectively. Phylogenetic analysis based on concatenated RdRP and CP amino acid sequences places CfVV1 within the genus Victorivirus of the recently established family Pseudototiviridae . Transmission electron microscopy confirmed the presence of isometric virus-like particles ca. 40 nm in diameter, consistent with the typical morphology of victoriviruses. To our knowledge, this is the first report of a complete victorivirus genome infecting C. falcatum .