Ralstonia solanacearum is the causal agent of the devastating bacterial wilt disease that attacks important agricultural crops such as potato, tomato, banana, among others, causing serious yield losses. Control of R. solanacearum is difficult because of its wide range of alternate hosts, its long survival in soil, its biological and genetic variation, the lack of natural resistance sources and the insufficiency of the appropriate chemical control measures. Quorum sensing is the term that describes the phenomenon whereby the accumulation of molecules allows bacteria to know the number of bacteria found in the environment (population density). R. solanacearum has a quorum sensing system for the regulation of the expression of virulence genes; the molecule 3-OH-PAME is the self-regulatory signal. The molecule ΒHPMEH hydrolyzes 3-OH-PAME nullifying the signal of virulence, and thus, the quo...

La marchitez bacteriana causada por Ralstonia solanacearum E.F. Smith es una de las enfermedades bacterianas más importantes que ataca a cultivos agrícolas como papa, tomate, banana, entre otros, causando grandes pérdidas en la producción. Desafortunadamente, su control ha sido difícil por su amplio rango de hospederos alternativos, su supervivencia en el suelo y su variación biológica y genética; así como porque no hay variedades con altos niveles de resistencia y porque no existe un control químico efectivo. Quorum sensing (percepción de quorum) es el fenómeno mediante el cual la acumulación de unas moléculas permite a una bacteria saber el número de bacterias que se encuentran en el medio es decir la densidad poblacional. La bacteria R. solanacearum posee un sistema quorum sensing para la regulación de la expresión de genes de virulencia, y en la cual la molécula 3-O...

Arracacha is a root crop cultivated in several countries of South America. The commercial product, which is the storage root, has multiple nutritional properties: its fine starch makes it easily digestible, and it contains high levels of calcium and vitamin A. High throughput sequencing (HTS) technology has been applied successfully for virus discovery in different agricultural crops, and it has been proposed to apply it in routine pathogen detection. Using HTS, novel sequences related to crinivirus and vitivirus were identified in apparently symptomeless arracacha, which were assembled into contigs located in different positions of the genome. Based on those sequences’ primers were designed to amplify corresponding sequences from further arracacha accessions and potato plant samples collected from farmers’ fields in Colombia and Peru. It was possible to determine the near complete g...

One of the future challenges to produce food in a Mars environment will be the optimization of resources through the potential use of the Martian substratum for growing crops as a part of bioregenerative food systems. In vitro plantlets from 65 potato genotypes were rooted in peat-pellets substratum and transplanted in pots filled with Mars-like soil from La Joya desert in Southern Peru. The Mars-like soil was characterized by extreme salinity (an electric conductivity of 19.3 and 52.6 dS m−1 under 1 : 1 and saturation extract of the soil solution, respectively) and plants grown in it were under sub-optimum physiological status indicated by average maximum stomatal conductance <50 mmol H2O m−2 s−1 even after irrigation. 40% of the genotypes survived and yielded (0.3–5.2 g tuber plant−1) where CIP.397099.4, CIP.396311.1 and CIP.390478.9 were targeted as promising materials with ...

The Oomycete Phytophthora infestans (Mont.) de Bary, the causal agent of the disease known as late blight, is primarily responsible for the decreased in production performance and potato crops worldwide. The integration of the complete Rgenes sequences in the potato genome using Agro-transformation appears an alternative to be considered in the fight against this pathogen. The Rpi-blb2 gene (Rgene) from the wild species Solanum bulbocastanumDunal shows a broad resistance to isolates ofP. infestans,making it an important candidate for plant breeding studies. This paper reports the integration of the Rpi-blb2gene into potato var. Désirée genome by Agrobacterium tumefaciens- mediated transformation system, the molecular characterization of 29 events transformed and whole plant infection with isolate POX67 of P. infestansfrom Peru. Désirée events [Rpi-blb2] 4 and Désirée [Rpi-blb2] 30,...

One of the most efficient options for the control of late blight disease in potato (Solanum tuberosum) is the development of resistant varieties to Phytophthora infestans mediated by the direct transfer of resistance (R) genes through genetic engineering. In the present work, we used Solanum bulbocastanum RB gene to confers broad spectrum resistance to P. infestans races. To that end, Agrobacterium - mediated genetic transformation was used to transform a susceptible potato variety, Desiree, with the binary vector pCIP68 harboring the RB gene. As a result, 19 transformed plants containing the RB gene were obtained. kanamycin resistance test and polymerase chain reaction (PCR) assays confirmed the integration of the T-DNA in the potato genome. The 19 transformed plants, also called transgenic events were subjected to infection under biosafety greenhouse conditions. Phytophthora infestans ...

The Oomycete Phytophthora infestans (Mont.) de Bary, the causal agent of the disease known as late blight, is primarily responsible for the decreased in production performance and potato crops worldwide. The integration of the complete Rgenes sequences in the potato genome using Agro-transformation appears an alternative to be considered in the fight against this pathogen. The Rpi-blb2 gene (Rgene) from the wild species Solanum bulbocastanumDunal shows a broad resistance to isolates ofP. infestans,making it an important candidate for plant breeding studies. This paper reports the integration of the Rpi-blb2gene into potato var. Désirée genome by Agrobacterium tumefaciens- mediated transformation system, the molecular characterization of 29 events transformed and whole plant infection with isolate POX67 of P. infestansfrom Peru. Désirée events [Rpi-blb2] 4 and Désirée [Rpi-blb2] 30,...

One of the most efficient options for the control of late blight disease in potato (Solanum tuberosum) is the development of resistant varieties to Phytophthora infestans mediated by the direct transfer of resistance (R) genes through genetic engineering. In the present work, we used Solanum bulbocastanum RB gene to confers broad spectrum resistance to P. infestans races. To that end, Agrobacterium - mediated genetic transformation was used to transform a susceptible potato variety, Desiree, with the binary vector pCIP68 harboring the RB gene. As a result, 19 transformed plants containing the RB gene were obtained. kanamycin resistance test and polymerase chain reaction (PCR) assays confirmed the integration of the T-DNA in the potato genome. The 19 transformed plants, also called transgenic events were subjected to infection under biosafety greenhouse conditions. Phytophthora infestans ...

Potato virus X (PVX) occurs worldwide and causes an important potato disease. Complete PVX genomes were obtained from 326 new isolates from Peru, which is within the potato crop′s main domestication center, 10 from historical PVX isolates from the Andes (Bolivia, Peru) or Europe (UK), and three from Africa (Burundi). Concatenated open reading frames (ORFs) from these genomes plus 49 published genomic sequences were analyzed. Only 18 of them were recombinants, 17 of them Peruvian. A phylogeny of the non-recombinant sequences found two major (I, II) and five minor (I-1, I-2, II-1, II-2, II-3) phylogroups, which included 12 statistically supported clusters. Analysis of 488 coat protein (CP) gene sequences, including 128 published previously, gave a completely congruent phylogeny. Among the minor phylogroups, I-2 and II-3 only contained Andean isolates, I-1 and II-2 were of both Andean and...

The evolutionary divergence of Potato mop-top virus (PMTV), a tri-partite, single-stranded RNA virus, is exceptionally low, based on the analysis of sequences obtained from isolates from Europe, Asia and North America. In general, RNA viruses exist as Dynamic populations of closely related and recombinant genomes that are subjected to continuous genetic variation. The reason behind the low genetic variation of PMTV remains unclear. The question remains as to whether the low variability is a shared property of all PMTV isolates or is a result of the limited number of isolates characterized so far. We hypothesized that higher divergence of the virus might exist in the Andean regions of South America, the centre of potato domestication. Here, we report high variability of PMTV isolates collected from 12 fields in three locations in the Andean region of Peru. To evaluate PMTV genetic variati...

Plant DNA and RNA extraction methods are well established, with a wide range of protocols, depending on the purposes of each laboratory/research. Nowadays, quick, inexpensive and easy plant DNA and RNA extraction methods are highly sought after. We developed an optimized protocol for plant DNA and RNA extraction that uses an inexpensive bench drill and plastic bags and does not require liquid nitrogen. DNA from leaves and RNA from leaves and roots of banana, pineapple, citrus, papaya, passion fruit and cassava, were extracted using a basic cetyltrimethylammonium bromide method. Both nucleic acids were quantified and evaluated for quality based on agarose gel electrophoresis. The DNA and RNA extractions were successful for all species, and RNA quality in pellets was maintained after storage at room temperature for three weeks. This protocol can reduce costs considerably in laboratories wi...