The morphology and physiology of the oogenesis have been well studied in the vector of Chagas disease Rhodnius prolixus. However, the molecular interactions that regulate the process of egg formation, key for the reproductive cycle of the vector, is still largely unknown. In order to understand the molecular and cellular basis of the oogenesis, we examined the function of the gene Bicaudal C (BicC) during oogenesis and early development of R. prolixus. We show that R. prolixus BicC (Rp-BicC) gene is expressed in the germarium, with cytoplasmic distribution, as well as in the follicular epithelium of the developing oocytes. RNAi silencing of Rp-BicC resulted in sterile females that lay few, small, non-viable eggs. The ovaries are reduced in size and show a disarray of the follicular epithelium. This indicates that Rp-BicC has a central role in the regulation of oogenesis. Although the follicular cells are able to form the chorion, the uptake of vitelline by the oocytes is compromised. We show evidence that the polarity of the follicular epithelium and the endocytic pathway, which are crucial for the proper yolk deposition, are affected. This study provides insights into the molecular mechanisms underlying oocyte development and show that Rp-BicC is important for de developmental of the egg and, therefore, a key player in the reproduction of this insect.

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This paper reports the first biological and molecular characterization of a nucleopolyhedrovirus isolated from the soybean and cotton pest Helicoverpa gelotopoeon. Studies were performed following a virus outbreak in a rearing facility and in wild H. gelotopoeon populations in Córdoba, Argentina. Host identity was corroborated by partial sequencing of the COI gene. Scanning electron microscope observations of purified OBs revealed their polyhedral morphology and an average diameter of 0.89±0.14μm. Ultrathin sections of infected larvae examined by transmission electron microscopy showed the intranuclear occurrence of polyhedra and virus particles in fat body cells. Nucleocapsids were singly enveloped. Phylogenetic analysis of lef-8, lef-9, polh, orf5/5b and hr3-orf62 viral sequences identified this new NPV isolate (hereafter HegeSNPV) as a variant of Helicoverpa armigera nucleopolyhedrovirus (HearNPV). Furthermore, HegeSNPV was closely related to the so-called "HzSNPV Group" within HearNPV, although having particular characteristics.

The South American soybean pest, Rachiplusia nu (Guenée), is naturally infected by Autographa californica multiple nucleopolyhedrovirus (AcMNPV) and Rachiplusia nu nucleopolyhedrovirus (RanuNPV). We compared their pathogenicity to fourth-instar R. nu larvae, by evaluating time to death and virus spread throughout the tissues in single and mixed infections. Bioassays showed that generalist AcMNPV had a faster speed of kill than specific RanuNPV, while the mixed-virus treatment did not statistically differ from AcMNPV alone. Histopathology evidenced similar tissue tropism for both viruses, but co-inoculation resulted in mostly AcMNPV-infected cells. In sequential inoculations, however, the first virus administered predominated over the second one. Implications on baculovirus interactions and biocontrol potential are discussed.

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11The morphology and physiology of the oogenesis have been well studied in 12 the vector of Chagas disease Rhodnius prolixus. However, the molecular 13 interactions that regulate the process of egg formation, key for the reproductive 14 cycle of the vector, is still largely unknown. In order to understand the molecular 15 and cellular basis of the oogenesis we examined the function of the gene 16 Bicaudal C (BicC) during oogenesis and early development of R. prolixus. We 17 show that R. prolixus BicC (Rp-BicC) gene is expressed in the germarium, with 18 cytoplasmic distribution, as well as in the follicular epithelium of the developing 19 oocytes. RNAi silencing of Rp-BicC resulted in sterile females that lay few, small, 20 non-viable eggs. The ovaries are reduced in size and show a disarray of the 21 follicular epithelium. This indicates that Rp-BicC has a central role in the 22 regulation of oogenesis. Although the follicular cells are able to form the chorion, 23 the uptake of vitelline by the oocytes is compromised. We show evidence that the 24 polarity of the follicular epithelium and the endocytic pathway, which is crucial for 25 the proper yolk deposition, are affected. This study provides insights into the 26 molecular mechanisms underlying oocyte development and show that Rp-BicC 27 is important for de developenta of the egg and, therefore, a key player in the 28 reproduction of this Chagas disease vector. 29 30 Author summary 31 The oogenesis is the process of egg formation. It is essential to guarantee 32 transgenerational inheritance. It implies the differentiation of the gamete (oocyte) 33 from a niche of stem cells in the germ line, the accumulation of yolk, and the 34 formation of the chorion. These events are entangled in a regulated manner by 35 the concerted communication between the different cell types that form the ovary. 36 It is regulated by endogenous gene networks and linked to the physiological state 37 of the insect by hormonal clues. This timely orchestrated process represents the 38 interaction of gene networks. The genetic regulation behind the oogenesis is 39 largely unknown in Rhodnius prolixus. Here we identified a gene required for egg 40 formation that interferes the uptake of the yolk by affecting the functional integrity 41 of the follicular epithelium. Our results are of interest for a better understanding 42 of a complex process essential for the survival of vector populations and provide 43 knowledge to envisage and design new strategies for vector control. 44 45 46 Introduction 47 Rhodnius prolixus, is a hematophagous insect and, like other triatomines, is 48 the vector of Trypanosoma cruzi, the agent of Chagas disease [1,2]. Chagas 49 disease is a life-threatening disease affecting millions of people worldwide [3]. As 50 vaccine are unavailable and disease treatment is unsafe, vector control is still the 51 most useful method to control the illness. In this context, as oogenesis is crucial 52 for embryo viability and population dynamics, molecular investigation on this 53...

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