Abstract. In the current study, the virulence factors in Escherichia coli isolates from bovine mastitis were investigated, and the connection between these factors and infection was evaluated using phenotypic and genotypic analyses. Twenty-seven E. coli isolates were analyzed, and 2 were shown to produce verotoxin. All isolates had the ability to produce biofilms, although at different levels. One isolate was found to be sensitive to the bactericidal activity of bovine serum, 11 were intermediate, and 15 were resistant. Some isolates showed resistance to trimethoprim sulfa (9) and ampicillin (4), intermediate resistance to neomycin (1) and trimethoprim sulfa (5), and simultaneous resistance to ampicillin and trimethoprim sulfa (4). The fimH gene was found in all isolates and was associated with other virulence markers: pap (1), stb (8), cs31a (3), stb and vt2 (2), cs31a and stb (3), east1 and kps (1), stb and east1 (1), cs31a and east1 (1), and cs31a, stb, pap, and iucD (1). Serogroups were determined for 3 isolates: O93:H4, O83:H19, and O15:H11. Phylogenetic analysis showed that 23 isolates belonged to group A and 4 belonged to B1. The findings revealed that these E. coli isolates are opportunistic pathogens with different virulence factors. The results indicate that the pathogenicity route of E. coli in bovine mastitis is not a consequence of 1 specific virulence factor.

The biological and molecular characterization of six isolates of a new Cowpea mild mottle virus strain (CPMMV; Carlavirus, Betaflexiviridae) are reported. Soybean plants with mosaic and stem necrosis were collected in Bahia, Goi as, Mato Grosso and Minas Gerais states, Brazil. Complete genomes of the CPMMV isolates are 8180-8198 nucleotides (nt) long, excluding the 3′-polyadenylated tail, and have 67-68% nt sequence identity with a Ghana isolate of CPMMV, the only CPMMV isolate for which the genome has previously been sequenced. The replicase has only 60-61% nt sequence identity with the Ghana CPMMV isolate, and the coat protein (CP) is highly conserved (79% nt sequence identity and 95-96% amino acid sequence identity). The high CP identity and the phylogenetic analyses supported the classification of the Brazilian isolates as CPMMV. Biological and molecular differences with the Ghana CPMMV isolate were found and indicated that the six isolates represent a distinct CPMMV strain denominated as CPMMV-BR. Furthermore, it is shown that recombination occurred mainly in the polymerase gene, and may occur less frequently in other regions of the CPMMV genome.

In this review we describe and discuss the biology and aspects of infection of a pathogen, the RNA virus Cowpea mild mottle virus (CPMMV), that emerged as a problem in soybean and is re-emerging in common bean. The review takes a global perspective but has an emphasis on Brazilian soybean in which CPMMV causes stem necrosis. Since its first description in Ghana in 1973, CPMMV has spread across the world and, although it principally infects Fabaceae, it is also able to infect hosts from Solanaceae and Lamiaceae. While the problem in soybean is being tackled with resistant varieties, CPMMV is re-emerging in genetically modified common bean. To limit the impact of CPMMV and combat future outbreaks, it is necessary to understand the ecological and evolutionary factors that influence its emergence. We identify surveillance as a key defense against CPMMV, as CPMMV is transmitted non-persistently by the whitefly Bemisia tabaci, there is the possibility of seed transmission and the virus is able to cause asymptomatic infections. We discuss the potential for development of resistant crop lines and identify key areas for future research.

Posing as one of the major threats for a wide range of plant species, viruses are responsible for huge losses in crop production around the world. The design of new efficient molecular strategies aiming plant resistance requires a holistic view of the complex mechanisms underlying the plant-virus interactions, as well as the discovery of all virus-associated functional components involved in disease. Most of plant viruses present RNA genomes, which aspects of structural diversity and function are frequently difficult to be described using classical molecular biology approaches. As a promising alternative, the advancing field of transcriptomics has shaded light on the understanding of a plethora of plant-virus interactions, in model and crop plants. The advent of RNA sequencing (RNA-seq) and its several variants, such as sRNA-seq and Degradome-seq, has brought the study of plant-virus interactions in a new age. Previously unknown players acting during virus infections are now structurally and functionally described. In this review, we focus on the advances of plant-virus interactions study promoted by the expanding field of transcriptomics. We present an overview of state-ofart of the plant-virus interactions study, regarding important aspects of plant physiology and virology, following by a succinct description of the main transcriptomic approaches used in this field. A detailed description of the use of transcriptomic approaches for some of main plant virus genres during host-interactions is also presented. Finally, we bring concluding remarks discussing the importance of transcriptomics in the study of plant viral diseases, and the future prospects of new approaches in transcriptomics with potential of use in plant-virus interaction studies. Keywords Functional genomics Á Plant physiology Á Plant virology Á Gene expression Á RNA-seq Larissa Goulart Zanardo and Gilza Barcelos de Souza have contributed equally to this manuscript.

Molecular variability was assessed for 18 isolates of cowpea mild mottle virus (CPMMV, genus Carlavirus, family Betaflexiviridae) found infecting soybean in various Brazilian states (Bahia, Goiás, Maranhão, Mato Grosso, Minas Gerais, Pará) in 2001 and 2010. A variety of symptoms was expressed in soybean cv. CD206, ranging from mild (crinkle/blistering leaves, mosaic and vein clearing) to severe (bud blight, dwarfing, leaf and stem necrosis). Recombination analysis revealed only one CPMMV isolate to be recombinant. Pairwise comparisons and phylogenetic analysis were performed for partial genomes (ORF 2 to the 3' terminus) and for each ORF individually (ORFs 2 to 6), showing the isolates to be distinct. The topology of the phylogenetic tree could be related to symptoms, but not to the year of collection or geographical origin. Additionally, the phylogenetic analysis supported the existence of two distinct strains of the virus, designated CPMMV-BR1 and CPMMV-BR2, with molecular variations between them.