Cassava Frogskin Disease: Current Knowledge on a Re-Emerging Disease in the Americas.

Cassava frogskin disease (CFSD) is a graft-transmissible disease of cassava reported for the first time in the 1970s, in Colombia. The disease is characterized by the formation of longitudinal lip-like fissures on the peel of the cassava storage roots and a progressive reduction in fresh weight and starch content. Since its first report, different pathogens have been identified in CFSD-affected plants and improved sequencing technologies have unraveled complex mixed infections building up in plants with severe root symptoms.

Tospoviruses Induce Small Interfering RNAs Targeting Viral Sequences and Endogenous Transcripts in Solanaceous Plants.

Tospoviruses infect numerous crop species worldwide, causing significant losses throughout the supply chain. As a defence mechanism, plants use RNA interference (RNAi) to generate virus-derived small-interfering RNAs (vsiRNAs), which target viral transcripts for degradation. Small RNA sequencing and in silico analysis of capsicum and infected by tomato spotted wilt virus (TSWV) or capsicum chlorosis virus (CaCV) demonstrated the presence of abundant vsiRNAs, with host-specific differences evident for each pathosystem.

Genome Analysis and Pathobiology of Cassava-Infecting Torradoviruses Containing a Putative Maf/HAM1 Pyrophosphatase Domain.

Next generation sequencing has been used to identify and characterize the full genome sequence of a cassava-infecting torradovirus, revealing the presence of a Maf/HAM1 domain downstream of the RNA-dependent RNA-polymerase (RdRp) domain in RNA1 in all isolates sequenced. A similar domain is also found in unrelated potyvirids infecting Euphorbiaceae hosts in the Americas and cassava in Africa. Even though cassava torrado-like virus (CsTLV) could not be mechanically transmitted to a series of herbaceous hosts, it can be efficiently transmitted by bud graft-inoculation to different cassava landraces.

An optimized nucleic acid isolation protocol for virus diagnostics in cassava ( Crantz.).

Our group works on the detection and characterization of cassava viruses, supporting projects that involve large scale pathogen surveillance activities and resistance screening assays in multiple and remote locations. In order to comply with these applications, nucleic acid isolation protocols need to be cost effective, adjusted for samples that will stand long distance transport and harsh storage conditions, while maximizing the yield and quality of the nucleic acid extracts obtained. The method we describe here has been widely used and validated using different downstream tests (including, but not limited to, Rolling Circle Amplification and Illumina and Nanopore sequencing), but is currently unpublished.

Viruses Without Borders: Global Analysis of the Population Structure, Haplotype Distribution, and Evolutionary Pattern of Iris Yellow Spot Orthotospovirus (Family , Genus ).

Iris yellow spot, caused by Iris yellow spot orthotospovirus (IYSV) (Genus: , Family: ), is an important disease of spp. The complete N gene sequences of 142 IYSV isolates of curated sequence data from GenBank were used to determine the genetic diversity and evolutionary pattern. restriction fragment length polymorphism (RFLP) analysis, codon-based maximum likelihood studies, genetic differentiation and gene flow within the populations of IYSV genotypes were investigated.

The (TSWV) Genome is Differentially Targeted in TSWV-Infected Tomato () with or without Gene.

Tospoviruses cause significant losses to a wide range of agronomic and horticultural crops worldwide. The type member, (TSWV), causes systemic infection in susceptible tomato cultivars, whereas its infection is localized in cultivars carrying the 5 resistance gene. The response to TSWV infection in tomato cultivars with or without -5 was determined at the virus small RNA level in the locally infected leaf.

Identification and localization of Tospovirus genus-wide conserved residues in 3D models of the nucleocapsid and the silencing suppressor proteins.

Background: Tospoviruses (genus Tospovirus, family Peribunyaviridae, order Bunyavirales) cause significant losses to a wide range of agronomic and horticultural crops worldwide. Identification and characterization of specific sequences and motifs that are critical for virus infection and pathogenicity could provide useful insights and targets for engineering virus resistance that is potentially both broad spectrum and durable. Tomato spotted wilt virus (TSWV), the most prolific member of the group, was used to better understand the structure-function relationships of the nucleocapsid gene (N), and the silencing suppressor gene (NSs), coded by the TSWV small RNA.

Unraveling complex viral infections in cassava (Manihot esculenta Crantz) from Colombia.

In the Americas, different disease symptoms have been reported in cassava including leaf mosaics, vein clearings, mottles, ring spots, leaf distortions and undeveloped and deformed storage roots. Some viruses have been identified and associated with these symptoms while others have been reported in symptomless plants or latent infections. We observed that reoviruses associated with severe root symptoms (RS) of Cassava Frogskin Disease (CFSD) are not associated with leaf symptoms (LS) observed in the cassava indicator plant 'Secundina'.