A Tomato-Free Period Delays and Reduces Begomovirus Disease in Processing Tomato Fields in a Complex Agroecosystem in Central Brazil.

A mandatory tomato-free period (TFP) was implemented in the state of Goiás, Brazil, in 2007 to help manage diseases caused by whitefly-transmitted begomoviruses. The impact of the TFP was examined in five locations across three states in Central Brazil from 2013 to 2016. Surveys revealed significant differences in begomovirus disease incidence among locations, i.

Isolation, characterization, and evaluation of putative new bacteriophages for controlling bacterial spot on tomato in Brazil.

Bacterial spot is a highly damaging tomato disease caused by members of several species of the genus Xanthomonas. Bacteriophages have been studied for their potential use in the biological control of bacterial diseases. In the current study, bacteriophages were obtained from soil and tomato leaves in commercial fields in Brazil with the aim of obtaining biological control agents against bacterial spot.

Metagenomic analyses of plant virus sequences in sewage water for plant viruses monitoring.

Unlabelled: Frequent monitoring of emerging viruses of agricultural crops is one of the most important missions for plant virologists. A fast and precise identification of potential harmful viruses may prevent the occurrence of serious epidemics. Nowadays, high-throughput sequencing (HTS) technologies became an accessible and powerful tool for this purpose.

Evidence of Spread of Bemisia tabaci (Hemiptera: Aleyrodidae) Mediated by Internal Transportation of Ornamental Plants in Brazil.

Two Bemisia tabaci (Gennadius) species, Middle East-Asia Minor 1 (MEAM1) and Mediterranean (MED), are major pests that are dispersed throughout the world. While MEAM1 was introduced in Brazil in the 1990s, MED was reported recently with limited spread. Here, a survey was performed to examine whether MED whiteflies are widely present in the Federal District region, in central Brazil.

A Temporal Diversity Analysis of Brazilian Begomoviruses in Tomato Reveals a Decrease in Species Richness between 2003 and 2016.

Understanding the molecular evolution and diversity changes of begomoviruses is crucial for predicting future outbreaks of the begomovirus disease in tomato crops. Thus, a molecular diversity study using high-throughput sequencing (HTS) was carried out on samples of infected tomato leaves collected between 2003 and 2016 from Central Brazil. DNA samples were subjected to rolling circle amplification and pooled in three batches, G1 (2003-2005, N = 107), G2 (2009-2011, N = 118), and G3 (2014-2016, N = 129) prior to HTS.

Characterization of an infectious clone of pepper ringspot virus and its use as a viral vector.

The genus Tobravirus comprises three species: Tobacco rattle virus, Pea early-browning virus and Pepper ringspot virus. The genomes of tobraviruses consist of two positive-sense single-stranded RNA segments (RNA1 and RNA2). Infectious clones of TRV are extensively used as virus-induced gene-silencing (VIGS) vectors for studies of virus-host interactions and functions of plant genes.

Cucurbit aphid-borne yellows virus from melon plants in Brazil is an interspecific recombinant.

Melon plants with severe yellowing symptoms from in Brazil were analyzed by high-throughput sequencing. Sequences homologous to the genome of the polerovirus cucurbit aphid-borne yellows virus (CABYV) were frequently retrieved. Two draft CABYV genomes were assembled from two pooled melon samples that contained an identical putative recombinant fragment in the 3' region with an unknown polerovirus.

Complete genome sequence of a proposed new tymovirus, tomato blistering mosaic virus.

In a previous work, a distinct tymovirus infecting tomato plants in Brazil was reported and tentatively named tomato blistering mosaic virus (ToBMV). In this study, the complete genome sequence of ToBMV was determined and shown to have a size of 6277 nucleotides and three ORFs: ORF 1 encodes the replication-complex polyprotein, ORF 2 the movement protein, and ORF 3 the coat protein. The cleavage sites of the replication-complex polyprotein (GS/LP and VAG/QSP) of ToBMV were predicted by alignment analysis of amino acid sequences of other tymoviruses.

Simplified methods for the construction of RNA and DNA virus infectious clones.

Infectious virus clones are one of the most powerful tools in plant pathology, molecular biology, and biotechnology. The construction of infectious clones of RNA and DNA viruses, however, usually requires laborious cloning and subcloning steps. In addition, instability of the RNA virus genome is frequently reported after its introduction into the vector and transference to Escherichia coli.

Unique RNA 2 sequences of two Brazilian isolates of Pepper ringspot virus, a tobravirus.

Pepper ringspot virus (PepRSV) is a tobravirus reported only in Brazil. Here, the sequences of the complete RNA 2 segments and the 3' end of the RNA 1 genomic regions of two new isolates from tomato plants were analyzed. The main ORF encodes the CP gene as other tobraviruses and termed ORF 1 of RNA 2.

The Tomato spotted wilt virus cell-to-cell movement protein (NSM ) triggers a hypersensitive response in Sw-5-containing resistant tomato lines and in Nicotiana benthamiana transformed with the functional Sw-5b resistance gene copy.

Although the Sw-5 gene cluster has been cloned, and Sw-5b has been identified as the functional gene copy that confers resistance to Tomato spotted wilt virus (TSWV), its avirulence (Avr) determinant has not been identified to date. Nicotiana tabacum 'SR1' plants transformed with a copy of the Sw-5b gene are immune without producing a clear visual response on challenge with TSWV, whereas it is shown here that N. benthamiana transformed with Sw-5b gives a rapid and conspicuous hypersensitive response (HR).

Complete sequence of a new bipartite begomovirus infecting cotton plants in Brazil.

Begomoviruses are plant viruses responsible for severe losses in important crops, such as beans, cassavas, tomatoes, and cotton, around the world. Here, we report the first full-genome sequence of a bipartite begomovirus species collected from cotton plants in Brazil.

Expression and assembly of Norwalk virus-like particles in plants using a viral RNA silencing suppressor gene.

Binary vector-based transient expression of heterologous proteins in plants is a very attractive strategy due to the short time required for proceeding from planning to expression. However, this expression system is limited by comparatively lower yields due to strong post-transcriptional gene silencing (PTGS) in the host plants. The aim of this study was to optimize a procedure for expression of norovirus virus-like particles (VLPs) in plants using a binary vector with co-expression of a PTGS suppressor to increase the yield of the target protein.

Characterization of a novel tymovirus on tomato plants in Brazil.

A tymovirus was isolated in Brazil from tomato plants with severe symptoms of leaf mosaic and blistering. The virus was mechanically transmissible to solanaceous indicator host species. The infected plants contained icosahedral particles and chloroplasts with membrane deformations which are typical cytopathic effects caused by tymoviruses.

Characterization of bean necrotic mosaic virus: a member of a novel evolutionary lineage within the Genus Tospovirus.

Background: Tospoviruses (Genus Tospovirus, Family Bunyaviridae) are phytopathogens responsible for significant worldwide crop losses. They have a tripartite negative and ambisense RNA genome segments, termed S (Small), M (Medium) and L (Large) RNA. The vector-transmission is mediated by thrips in a circulative-propagative manner.

An RNA-dependent RNA polymerase gene of a distinct Brazilian tospovirus.

The tospoviral RNA-dependent RNA polymerases (RdRp), or L proteins, perform several conserved functions during virus replication in host cells. In this study, an L segment sequence of 9,040 bp from a new tospovirus (family Bunyaviridae) naturally infecting bean (Phaseolus vulgaris L.) plants was characterized.

Characterization of a member of a new Potyvirus species infecting arracacha in Brazil.

An arracacha (Arracacia xanthorrhiza) plant collected in Brazil was found to be infected by a new virus. This viral isolate (named C17) systemically infected Nicotiana benthamiana and Apium graveolens. A polyclonal antibody was raised, and analysis of our arracacha germplasm collection showed a high infection rate of C17-like viruses (93% infection).

The N protein of Tomato spotted wilt virus (TSWV) is associated with the induction of programmed cell death (PCD) in Capsicum chinense plants, a hypersensitive host to TSWV infection.

In sweet pepper, the Tsw gene, originally described in Capsicum chinense, has been widely used as an efficient gene for inducing a hypersensitivity response (HR) derived Tomato spotted wilt virus (TSWV) resistance. Since previously reported studies suggested that the TSWV-S RNA mutation(s) are associated with the breakdown of Tsw mediated TSWV resistance in peppers, the TSWV genes N (structural nucleocapsid protein) and NS(S) (non-structural silencing suppressor protein) were cloned into a Potato virus X (PVX)-based expression vector, and inoculated into the TSWV-resistant C. chinense genotype, PI 159236, to identify the Tsw-HR viral elicitor.

Diversity and prevalence of Brazilian bipartite begomovirus species associated to tomatoes.

Information on the distribution and prevalence of the economically destructive Begomovirus species and recombinant forms infecting fresh-market and processing tomato crops in Brazil is crucial in guiding breeding programs and also to understand the evolutionary mechanisms associated with the upsurge of so many species and quasi-species comprising this unique disease complex. An extensive survey was carried out over 3 years (between 2002 and 2004) aiming to study the diversity of begomoviruses in tomato plants, predominantly collected in central Brazil. Polymerase chain reaction (PCR) with degenerated primers was used to detect the begomoviruses in tomato leaf samples showing virus-like symptoms in commercial fields.

One-step cloning approach for construction of agroinfectious begomovirus clones.

Most begomoviruses have a bipartite genome containing two circular ssDNA segments (DNA-A and DNA-B). Routine infectious clone construction relies upon cloning of the whole genome, which is then subcloned as a tandem one-and-half or two genome- (containing two replication origins) cassette into a vector prior to agro-inoculation. The construction of cassettes containing two replication origins is, however, a time-consuming process.

The glycoprotein gene of Chrysanthemum stem necrosis virus and Zucchini lethal chlorosis virus and molecular relationship with other tospoviruses.

Two tospoviruses, Chrysanthemum stem necrosis virus (CSNV) and Zucchini lethal chlorosis virus (ZLCV), cause economical losses in several ornamental and vegetable crops in Brazil. The nucleocapsid gene and movement protein sequences had already been reported for both viruses, though the glycoprotein precursor gene sequence was not available. In this study, cDNA fragments (ca.

Genome analysis of a severe and a mild isolate of Papaya ringspot virus-type W found in Brazil.

Papaya ringspot virus-type W (PRSV-W) is one of the most economically threatening viruses of cucurbits in Brazil. Premunization is one of the most effective PRSV control measures currently applied in squash and zucchini crops. PRSV-W-1, a mild and premunizing strain of PRSV has been successfully used to protect cucurbits against both the severe PRSV-W-C strain and other Brazilian PRSVs.

Bidens mosaic virus is a member of the Potato virus Y species.

The nucleotide sequence of the genomic 3' terminal region (1,702 bases) of two Brazilian Bidens mosaic virus isolates (BiMV: BiMV-p and BiMV-b) was determined. BiMV-p and BiMV-b share 98% nucleotide sequence identity, and are most closely related to members of the potyvirus species: Sunflower chlorotic mottle virus (an isolate of Potato virus Y) and Potato virus Y. BiMV-p shares 88% capsid protein amino acid identity and 77% 3'UTR nucleotide sequence identity with SuCMoV an isolate of Sunflower chlorotic mottle virus.

Sequence analysis of the glycoproteins of Tomato chlorotic spot virus and Groundnut ringspot virus and comparison with other tospoviruses.

The tospoviruses Tomato chlorotic spot virus (TCSV) and Groundnut ringspot virus (GRSV) cause high economic losses in several vegetable crops in Brazil. The glycoprotein precursor coding sequence was still not available for these two viruses. In this study, the 3' 4 kb M RNA of TCSV and GRSV genome was cloned and sequenced.