We present a procedure to explore the global dynamics shared between members of the same protein family. The method allows the comparison of patterns of vibrational motion obtained by Gaussian network model analysis. After the identification of collective coordinates that were conserved during evolution, we quantify the common dynamics within a family. Representative vectors that describe these dynamics are defined using a singular value decomposition approach. As a test case, the globin heme-binding family is considered. The two lowest normal modes are shown to be conserved within this family. Our results encourage the development of models for protein evolution that take into account the conservation of dynamical features.

BackgroundEpinotia aporema (Lepidoptera: Tortricidae) is an important pest of legume crops in South America. Epinotia aporema granulovirus (EpapGV) is a baculovirus that causes a polyorganotropic infection in the host larva. Its high pathogenicity and host specificity make EpapGV an excellent candidate to be used as a biological control agent.ResultsThe genome of Epinotia aporema granulovirus (EpapGV) was sequenced and analyzed. Its circular double-stranded DNA genome is 119,082 bp in length and codes for 133 putative genes. It contains the 31 baculovirus core genes and a set of 19 genes that are GV exclusive. Seventeen ORFs were unique to EpapGV in comparison with other baculoviruses. Of these, 16 found no homologues in GenBank, and one encoded a thymidylate kinase. Analysis of nucleotide sequence repeats revealed the presence of 16 homologous regions (hrs) interspersed throughout the genome. Each hr was characterized by the presence of 1 to 3 clustered imperfect palindromes which are similar to previously described palindromes of tortricid-specific GVs. Also, one of the hrs (hr4) has flanking sequences suggestive of a putative non-hr ori. Interestingly, two more complex hrs were found in opposite loci, dividing the circular dsDNA genome in two halves. Gene synteny maps showed the great colinearity of sequenced GVs, being EpapGV the most dissimilar as it has a 20 kb-long gene block inversion. Phylogenetic study performed with 31 core genes of 58 baculoviral genomes suggests that EpapGV is the baculovirus isolate closest to the putative common ancestor of tortricid specific betabaculoviruses.ConclusionsThis study, along with previous characterization of EpapGV infection, is useful for the better understanding of the pathology caused by this virus and its potential utilization as a bioinsecticide.

Highlights• We characterized the genomic diversity within a population of SfMNPV.• Coding regions with higher genetics diversity are associated with oral infectivity or unknown functions. • Several structural variants contribute to the genomic diversity of SfMNPV.• Sf29, a putative collagenase, shows signs of adaptive evolution. 2.

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A new isolate of the Spodoptera frugiperda granulovirus, SfGV ARG, was completely sequenced and analyzed. The SfGV ARG genome is 139,812 bp long and encodes 151 putative open reading frames. Of these ORFs, 56 were found in betabaculoviruses, 19 of which are present only in GVs closely related to SfGV. Seven ORFs found homologs in this small GV group and also in noctuid NPVs. ORF066 codes a 74 amino acid protein, overlapped with nudix gene, with several homologs in baculovirus, found by tblastn search. Comparison with the genome of the Colombian isolate SfGV VG008 resulted in SfGV being 1101 bp smaller and lacking a homologue of VG008 ORF084, which codes for Lef-7. However, we found that ORF051 shows remote homology to Lef-7 proteins. Moreover, analysis of ORF051 along with Lef-7 proteins coded by a group of noctuid specific GVs and NPVs indicated that Lef-7 proteins coded by these viruses include three F-box domains in contrast to the single one reported for AcMNPV Lef-7. SfGV ARG genome also contains a split photolyase as a distinct feature not found in VG008. BlastX analysis revealed that a complete photolyase is coded considering a putative frameshift in a poly-A tract, which resembles known slippery sequences involved in programmed ribosome frameshifting.

The fall armyworm, Spodoptera frugiperda (JE Smith) is a key pest in the Americas. Control strategies are mainly carried out by use of chemical insecticides and transgenic crops expressing Bacillus thuringiensis toxins. In the last years, resistance of S. frugiperda populations to transgenic corn was reported in different Latin American countries. The baculovirus Spodoptera frugiperda Multiple Nucleopolyhedrovirus (SfMNPV) is a pathogenic agent for the fall armyworm and a potential alternative for its control in integrated pest management strategies. In this work, we analyze some characteristics of two baculovirus isolates collected from maize (SfMNPV-M) and cotton (SfMNPV-C) fields from Argentina. The isolates were compared by restriction enzymes patterns and the analysis reveals the presence of genotypic variants in the SfMNPV-M isolate. We confirmed a deletion by sequencing fragments encompassing egt gene and most part of its contiguous gene (orf A) in a SfMNVP-M genotypic variant. Additionally, we estimated the 50% lethal dose and median survival time of each isolate in bioassays with S. frugiperda larvae. Keywords Fall armyworm • SfMNPV isolates • Biological control • Baculovirus • Agricultural pestThe fall armyworm, Spodoptera frugiperda (JE Smith) (Lepidoptera: Noctuidae) is an important pest of maize and other crops in the Americas [1, 2] and has been recently reported in Africa [3]. Management of the fall armyworm is mainly carried out through the use of chemical insecticides and transgenic crops expressing Bacillus thuringiensis toxins [4]. In recent years, resistance of S. frugiperda populations to transgenic corn was reported in Puerto Rico, . Therefore, the use of biological control agents as an alternative for the integrated management of the fall armyworm has gained renewed interest.The baculovirus Spodoptera frugiperda Multiple Nucleopolyhedrovirus (SfMNPV) is the main pathogen causing epizootic outbreaks in natural populations of the fall armyworm [8,9]. Several studies have shown that baculoviruses adapt to their local host populations and do not present the same performance when applied to host populations from different regions [10,11]. Therefore, it is required to study different isolates to rationally select the best biocontrol agent to a specific location. Currently, there are five complete SfM-NPV genomes available in GenBank [12][13][14][15]. The in silico analysis of their restriction endonuclease (REN) patterns evidences variation observed experimentally in SfMNPV isolates reported in early studies [9,[16][17][18].Edited by A. Lorena Passarelli.

The main function of baculoviral chitinase protein (V-CHIA) is to promote the final liquefaction of infected host larvae, facilitating the dispersion of occlusion bodies (OBs) in the environment. In this study, a v-chiA from Epinotia aporema Granulovirus (EpapGV) was identified and characterized. The 1,713 base pairs long open reading frame encodes a protein of 570 amino acids with a predicted molecular weight of 63 kDa. EpapGV V-CHIA sequence alignment resulted 62 % identical to Pieris rapae GV and Blastp search revealed a high conservation among all baculovirus chitinases. Amino acid sequence analysis indicated that the C-terminal KDEL present in most alphabaculovirus chitinases is absent in EpapGV V-CHIA, as well as in the rest of the betabaculoviruses. Phylogenetic analysis was performed with bacterial, lepidopteran, and baculoviral chitinase sequences available in databases. Using an AcMNPV bacmid (bApGOZA) a recombinant Ac-chiAEpapGV was obtained in order to overexpress EpapGV V-CHIA in cell culture. The presence of chitinase was detected in purified AcMNPV-chiAEpapGV OBs. Peritrophic membranes of Anticarsia gemmatalis larvae fed with recombinant OBs showed an altered structure. The results presented in this study show that EpapGV chitinase overexpression in recombinant baculovirus can cause association of this protein with OBs, and suggest that this could be used to evaluate the protein role in early stages of baculoviral infections.

Anticarsia gemmatalis is an important pest in legume crops in South America and it has been successfully controlled using Anticarsia gemmatalis Multiple Nucleopolyhedrovirus (AgMNPV) in subtropical climate zones. Nevertheless, in temperate climates its speed of kill is too slow. Taking this into account, genetic modification of AgMNPV could lead to improvements of its biopesticidal properties. Here we report the generation of a two-component system that allows the production of recombinant AgMNPV. This system is based on a parental AgMNPV in which the polyhedrin gene (polh) was replaced by a bacterial β-galactosidase (lacZ) gene flanked by two target sites for the homing endonuclease I-PpoI. Co-transfection of insect cells with linearized (I-PpoI-digested) parental genome and a transfer vector allowed the restitution of polh and the expression of a heterologous gene upon homologous recombination, with a low background of non-recombinant AgMNPV. The system was validated by constructing a recombinant occlusion-positive (polh+) AgMNPV expressing the green fluorescent protein gene (gfp). This recombinant virus infected larvae normally per os and led to the expression of GFP in cell culture as well as in A. gemmatalis larvae. These results demonstrate that the system is an efficient method for the generation of recombinant AgMNPV expressing heterologous genes, which can be used for manifold purposes, including biotechnological and pharmaceutical applications and the production of orally infectious recombinants with improved biopesticidal properties.