Browsing by Autor "G. Plata"

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Aptitud combinatoria de la resistencia al tizón tardío (Phytophthora infestans) en cultivares nativos de papa
(2016) Julio Gabriel; L. Orellana; G. Plata; Melicio Siles
En el Centro Toralapa en Cochabamba, Bolivia, se realizaron cruzamientos de 10 variedades nativas de papa resistentes al tizón tardío de la papa (Phytophthora infestans) del banco de germoplasma de papa en diseño dialélico triangular simple. Las progenies fueron alojadas en diseño de bloques completos al azar. Los objetivos de la investigación fueron caracterizar y seleccionar genotipos de papa con resistencia a tizón tardío en invernadero, mediante la medición del Área Bajo la Curva de Progreso de Phytophthora infestans (ABCPPI). Los resultados mostraron 67% de plántulas susceptibles y 33% de plántulas resistentes. Se observó que las progenies de los cruzamientos Bol 2835 x Morapapa, Polonia x Bol 1164; Bol 3147 x Bol 2718 y Bol 3147 x Polonia, Bol 2835 x Morapapa ; Bol 3147 x Bol 2718 y Waych’a x Bol 3147 tuvieron altos niveles de resistencia al tizón. Los progenitores Bol 3147, Bol 2835, Morapapa y Polonia mostraron una varianza significativa de la Aptitud Combinatoria Específica (ACE) en plántula. En plantas jóvenes se observó 16% de susceptibles y 84% de resistentes. La varianza de los efectos de la Aptitud Combinatoria General (ACG), mostró diferencias significativas para los cultivares Bol 3147, Bol 2835, Morapapa y Polonia. Estos resultados confirmaron lo observado para plántula en Polonia, Bol 2835 y Bol 3738. Las familias 00-223 (Polonia x Morapapa), y 00-224 (Polonia x Bol 1164) mostraron que la ACE fue más importante.Aceptado para publicación: Junio 15, 2011.
‘Candidatus Phytoplasma lycopersici’, a phytoplasma associated with ‘hoja de perejil’ disease in Bolivia
(Microbiology Society, 2007) Y. Arocha; O. Antesana; E. Montellano; Pablo Franco; G. Plata; P. Jones
New diseases known locally as 'hoja de perejil' of tomato (Lycopersicon esculentum Mill) and 'brotes grandes' of potato (Solanum tuberosum L.) were first recognized in surveys of production fields in Bolivia during 2000-2003. Alfalfa (Medicago sativa) witches' broom and little leaf diseases of native weeds Morrenia variegata and mora-mora (Serjania perulacea) were also identified near to production fields. Phytoplasma aetiology was attributed to each of these diseases following detection and initial identification of aster yellows group (16SrI) phytoplasmas in all five diseased plant species. While potato, alfalfa and mora-mora plants contained indistinguishable 16SrI-B strains, 'hoja de perejil' (THP) and morrenia little leaf (MVLL)-associated phytoplasma strains shared 97.5 % 16S rRNA gene sequence similarity with 'Candidatus Phytoplasma asteris' and related strains and <95 % similarity with all other 'Candidatus Phytoplasma' species. Phylogenetic analysis of 16S rRNA gene sequences indicated that the THP and MVLL phytoplasmas represent a novel lineage within the aster yellows (16SrI) group and, on the basis of unique 16S rRNA gene sequences, we propose that THP and MVLL phytoplasmas represent 'Candidatus Phytoplasma lycopersici', with THP as the reference strain.
Characterization of the resistance to Phytophthora infestans in local potato cultivars in Bolivia
(Springer Science+Business Media, 2006) Julio Gabriel; Alejandro Coca; G. Plata; J. E. Parlevliet
Correlación fenotípica y genotípica-molecular de la resistencia a enfermedades en variedades mejoradas de papa (Solanum tuberosum L.)
(Selva Andina Research Society, 2015) Mariela Baldelomar; Julio Gabriel; Silene Veramendi; Ariana Terán; G. Plata
En dos campañas consecutivas
First report of a ‘ Candidatus Phytoplasma asteris’ isolate associated with a witches’ broom disease of alfalfa in Bolivia
(Wiley, 2005) Peter Jones; Y. Arocha; G. Plata
During a survey in 2003, alfalfa (Medicago sativa) plants showing typical phytoplasma witches’ broom and little leaf symptoms were collected from fields in Limon Pampa, Rio Chico, Bolivia. Samples were evaluated by nested PCR using 16S rDNA primers P1/P7 and R16F2n/R16R2. PCR products of ≈1250 bp, and identical RFLP profiles following digestion with the restriction endonucleases HaeIII, RsaI and AluI were produced for all samples. PCR products were purified and directly sequenced, and the sequence deposited in GenBank (accession no. AY 725211). The sequence was compared with those of other phytoplasmas in GenBank using the blast protocol, and had the highest similarity (98%) with the phytoplasma from ash witches’ broom disease (GenBank accession no. AY568302), a member of the 16SrI aster yellows group (‘Candidatus Phytoplasma asteris’) (Firrao et al., 2004). Alfalfa witches’ broom diseases caused by phytoplasmas have been reported from Canada (‘Ca. Phytoplasma trifolii’, Khadhair & Hiruki, 1995; Firrao et al., 2004); Italy (‘Ca. Phytoplasma phoenecium’, Marcone et al., 1997; Firrao et al., 2004); and Oman (‘Ca. Phytoplasma aurantifolia’, Khan et al., 2001; Firrao et al., 2004). This is the first record of alfalfa witches’ broom disease in Bolivia, and the first report of an isolate of ‘Ca. Phytoplasma asteris’ infecting alfalfa. This work was supported by the Department for International Development (UK) through the Global Plant Clinic. Work in the UK was done under Defra plant health licence no. 174B/4612(09/2003). Y. Arocha thanks the Royal Society (UK) for financial support.
First report of a 16SrIII phytoplasma (X‐disease group) affecting bell pepper, strawberry (frutilla), Schinus molle and Arracacia xanthorrhiza in Cochabamba, Bolivia
(Wiley, 2010) Y. Arocha; G. Plata; Javier Franco; Gladys Main; Silene Veramendi; F. Lazcano; José L. Crespo; V. Lino; Claudene Menezes Atayde Calderon; Rodolfo Plana Llerena
Bell pepper (Capsicum annuum) and strawberry (Fragaria chiloensis, ‘frutilla’ in Spanish) are crops grown for local consumption in plots at the PROINPA Foundation, Cochabamba. Schinus molle (family Anacardiaceae, known locally as ‘molle’) is an ornamental tree widely distributed in Cochabamba urban areas, including PROINPA surroundings. Recently, symptoms of leaf size reduction and yellowing, proliferation, and shortening of internodes were observed in S. molle trees. Strawberry plants displayed rosette formation and small fruits, while bell pepper showed leaf size reduction and shortening of internodes. Symptoms were present in about 30% of strawberry and bell pepper plots, and more than 50% of the S. molle trees surrounding PROINPA exhibited symptoms. Arracacia xanthorrhiza, a nearby-grown vegetable in the celery family (Apiaceae), displayed leaf yellowing and little leaf. Symptom-bearing plants of bell pepper (4), S. molle (5), strawberry (4) and A. xanthorrhiza (4) were collected, as well as one symptomless plant of each plant species. Total DNA from leaf midribs was extracted and indexed by a nested PCR with universal 16S rRNA primers R16mF2/R1 and fU5/rU3. PCR amplicons (approximately 880 bp) were produced for almost all symptom-bearing plants, except for one plant of strawberry and one plant of A. xanthorrhiza. Symptomless plants did not yield amplicons. PCR amplicons were purified (Wizard, Promega), cloned (pGEMT-Easy Vector, Promega) and sequenced (http://www.dnaseq.co.uk). The 16S rRNA sequences of phytoplasmas detected in bell pepper (GenBank Accession No. FJ207456), strawberry (FJ207455), S. molle (FJ207454) and A. xanthorrhiza (FJ207451) showed the highest identity of 99% with the members of phytoplasma group 16SrIII (X-disease). A 16SrIII phytoplasma has been previously reported in Bolivia affecting chinaberry (Melia azadarach) trees (Harrison et al., 2003), but this is the first report of phytoplasmas belonging to group 16SrIII in bell pepper, strawberry, S. molle, and A. xanthorrhiza in Cochabamba, Bolivia. Work in the UK was done under Defra licence No. PHF 174D/5185 (08/2005). Rothamsted Research receives grants from BBSRC, UK.
Identification, characterization, antimicrobial activity and biocontrol potential of four endophytic fungi isolated from Amazonian plants
(Nature Portfolio, 2025) Sonia Mendieta-Brito; Mahmoud Sayed; Faqiha Ali Hamza; Eunjung Son; Dong-Seon Kim; G. Plata; Marcelo Dávila; Sang‐Hyun Pyo
Endophytic fungi, which reside within plants without causing disease, are recognized for their ability to produce bioactive metabolites with antibacterial, antifungal, and antioxidant properties, as well as their role in enhancing plant defense mechanisms. Due to these valuable traits, endophytic fungi have attracted significant attention in biotechnology and microbiology. The four endophytic fungal strains were isolated from the leaves of four Amazonian plant species—Piper heterophyllum Ruiz & Pav. (Paichané negro), Peperomia sp., Faramea multiflora A. Rich. ex DC.(Yuracaré), and Dictyoloma vandellianum A. Juss. (Sombrerillo). Molecular identification via 18 S rDNA sequencing and NCBI-BLAST analysis, as well as morphological characterization, were carried out for the isolates. Ethyl acetate extracts were obtained from both the growth medium and the fungal biomass. Thin-layer chromatography (TLC) combined with various staining techniques was used to identify the main groups of chemical compounds present in the extracts. The extracts were then assessed for antibacterial activity through a minimum inhibitory concentration (MIC) assay. The antagonistic potential of four endophytic fungi was evaluated through confrontation with phytopathogenic fungi using the dual culture plate assay. The results from molecular and morphological identification revealed two Aspergillus strains (SMB-18 and SMB-22), one Fusarium strain (SMB-20), and one Alternaria strain (SMB-28). Chemical profiling revealed a diverse composition, including carotenoids, terpenes, flavonoids, and phenolic compounds. The MIC assay demonstrated strong antibacterial activity against Gram-positive bacteria (Staphylococcus aureus, Enterococcus faecalis, and Propionibacterium acnes), with MIC values ranging from 15.6 to 500 µg/mL. Additionally, antagonistic and biocontrol assays using dual-culture tests showed strong antifungal activity. Strains SMB-18, SMB-20, and SMB-22 effectively inhibited Helminthosporium sp. (58–80%), Fusarium oxysporum (37–50%), and Fusarium solani (51–57%), the well-known phytopathogenic fungi that affect potato crops. These findings highlight the potential of Amazonian endophytic fungi as sources of bioactive metabolites with promising applications in agriculture, medicine, and biotechnology, reinforcing the importance of biodiversity in bioprospecting.
Niveles de resistencia al tizón tardío en clones de papa del Centro Internacional de la Papa (CIP) evaluados en Bolivia
(2016) Julio Gabriel; Silvia Fernández; G. Plata; Molina Siles
Este estudio fue realizado en el Centro Toralapa, Cochabamba, Bolivia durante el periodo 2001-2002 y 2002-2003, con el objetivo de evaluar la resistencia a Phytophthora infestans y verificar la ausencia de genes R en la población LBr3 del Centro Internacional de la Papa (CIP). El estudio se llevo a cabo en base a tres componentes: (i) resistencia medida por el tamaño de la lesión (TL). (ii), Rango de crecimiento de la lesión (RCL) y (iii) intensidad de esporulación (IE) a diferentes edades de plantas. Se utilizaron 25 clones de papa, aparentemente libres de genes R. Para el estudio de los componentes de resistencia se utilizó un aislamiento complejo y se determinó la presencia de genes R usando una raza simple. La evaluación del TL, RCL e IE, identificó a 5 clones: 391696.96, 392637.10, 392661.18, 393280.64 y 393280.82 con buenos niveles de resistencia parcial y libres de genes R. Se observó que en plantas jóvenes y susceptibles, Phytophthora infestans se desarrollo más rápidamente que en clones resistentes e hipersensibles. Las correlaciones encontradas entre las plantas provenientes de cultivo in vitro y tubérculos para los componentes de resistencia estudiados, fueron positivas y altamente significativas.Aceptado para publicación: Junio 15, 2011.
Occurrence of ‘ Candidatus Phytoplasma aurantifolia’ (16SrII group) in Bolivia
(Wiley, 2010) Y. Arocha; G. Plata; Javier Franco; Gladys Main; Silene Veramendi; F. Lazcano; José L. Crespo; V. Lino; Claudia Vargas Calderón; R. E. Espino Llerena
During a survey for phytoplasma at the PROINPA Foundation, Cochabamba, Bolivia in June 2008, plants of podocarpus (Podocarpus macrophyllus) showed symptoms of shortened internodes, leaf size reduction and proliferation compared to healthy ones, while those of rose (Rosa sp.) exhibited little leaf and yellowing. Both podocarpus and rose are widely distributed ornamental plants in the urban area of Cochabamba, and symptoms were observed in at least 20% of plants of each species surveyed at PROINPA. In addition, symptoms of leaf deformation, crinkling, and curling were displayed by wild plants of tomatillo (Physalis ixocarpa) growing nearby. Three plants with symptoms and one symptomless plant respectively of each species were collected. A nested PCR with universal 16S rRNA gene primers R16mF2/R1 and fU5/rU3 was carried out from total DNAs extracted from collected plant material. All plants with symptoms yielded PCR amplicons (∼880 bp), whilst the symptomless plants did not. PCR products were purified (Wizard, Promega), cloned (pGEM T-Easy Vector, Promega) and sequenced (http: http://www.dnaseq.co.uk). A representative sequence was deposited in GenBank for podocarpus (FJ207457), rose (FJ207453) and tomatillo (FJ207452). BLAST comparisons indicated that the 16S rDNA sequences of these phytoplasmas showed the highest identity (99%) with those of phytoplasma members of group 16SrII, ‘Candidatus Phytoplasma aurantifolia’. A disease in tomatillo was recently associated with a ‘Ca. Phytoplasma asteris’-related strain in Mexico (Santos-Cervantes et al., 2007). However, no phytoplasmas have been reported associated with diseases in podocarpus or rose in the region. This is the first report of phytoplasmas of group 16SrII in Bolivia and its association with diseases in podocarpus, tomatillo and rose plants. Work in the UK was done under Defra licence No. PHF 174D/5185(08/2005). Rothamsted Research receives grants from BBSRC, UK.
Phenotypic and molecular-genotypic correlation of diseases resistance in improved varieties potato (Solanum tuberosum L.)
(2015) Mariela Baldelomar; Julio Gabriel; Silene Veramendi; Ariana Terán; G. Plata
In two consecutive agricultural campaigns (2010-2011 and 2011-2012), 18 improved potato varieties were planted in the PROINPA Foundation greenhouses as well as two witness varieties (Waych’a and Desirée) with the aim to study: i) late blight resistance (Phytophthora infestans), wart (Synchytrium endobioticum) an virus PVX and ii) validate molecular markers GP94, RB, CP60 and NL25 for co-localizing with major resistance genes of diseases mentioned. The results showed significant differences among varieties for AUDPCrel (late blight), severity (Wart) and severity and absorbance (PVX). Different levels of resistance were observed in varieties, such varieties with high resistance and moderate resistance. Molecular analysis were highly significant to Pr<0.01 of probability for three of the market used. It was observed that the allele for marker GP94 was co-located with the resistance gene Rpi-phu1 for late blight at a distance of 350 bp, showing the resistance allele in all varieties except the Waych'a variety. The allele for RB marker that is co-localizes with the RB gene for resistance to blight was not found in any of the varieties tested. The allele for marker CP60 was co-located with Rx1 gene to PVX resistance at a distance of 350 bp and it was observed in almost all varieties except Chota Ñawi variety. Finally, the allele for marker NL25 is co-located with Sen1 gene resistance to wart at a distance of 1000 bp and it was observed in all varieties.
Resistencia genética de híbridos de tomate [Solanum lycopersicum L. (Mill.)] al virus del bronceado (TSWV)
(University of Costa Rica, 1969) Julio Gabriel; Daniel Alexander Céspedes Sanabria; Silene Veramendi; G. Plata; Ada Angulo; Mario Crespo
La presente investigación se realizó en el invernadero y laboratorio de la Fundación PROINPA en Cochabamba - Bolivia en el 2012. El objetivo fue evaluar la resistencia y suscep- tibilidad de plantas a los virus Tomato spotted wilt virus – TSWV, Tomato cholorotic spot virus – TCSV y Groundnut ringspot virus – GRSV en 10 híbridos de tomate mediante evaluación feno- típica y del patrón molecular (marcador SCAR Sw- 421), que distingue los homocigotos y hete- rocigotos resistentes del susceptible. Los resul- tados mostraron que el marcador SW-421 se co- localizó con el gen Sw-5 de resistencia a TSWV. Se observó la presencia de la banda de resistencia (R) para TSWV a 940 bp en las variedades PROINPA 2 (Aguaí) y PROINPA 9 (Bonita) en estado homocigoto dominante (Sw-5/Sw-5). Las variedades PROINPA 1 (Andinita), PROINPA 3 (Arami), PROINPA 4 (Yara), PROINPA 5 (Pintona), PROINPA 6 (Jasuka), y PROINPA 10 (Bola Pera), mostraron la banda resistencia (H) a TSWV a 900-940 bp en estado heterocigoto (Sw-5/Sw-5+). Solamente la variedad PROINPA 7 (Redonda), el padre 71 89S LACHING SW-5 y la variedad Shannon mostraron el gen de suscep- tibilidad (S) al TSWV a 900 bp en estado homo- cigoto recesivo (Sw-5+/Sw-5+). Los análisis de severidad y de DAS-ELISA fueron confirmados con el análisis molecular.
The expansion of brown rot disease throughout Bolivia: possible role of climate change
(Canadian Science Publishing, 2016) José A. Castillo; G. Plata
Bacterial wilt is a devastating plant disease caused by the bacterial pathogen Ralstonia solanacearum species complex and affects different crops. Bacterial wilt infecting potato is also known as brown rot (BR) and is responsible for significant economic losses in potato production, especially in developing countries. In Bolivia, BR affects up to 75% of the potato crop in areas with high incidence and 100% of stored potatoes. The disease has disseminated since its introduction to the country in the mid-1980s mostly through contaminated seed tubers. To avoid this, local farmers multiply seed tubers in highlands because the strain infecting potatoes cannot survive near-freezing temperatures that are typical in the high mountains. Past disease surveys have shown an increase in seed tubers with latent infection in areas at altitudes lower than 3000 m a.s.l. Since global warming is increasing in the Andes Mountains, in this work, we explored the incidence of BR in areas at altitudes above 3000 m a.s.l. Results showed BR presence in the majority of these areas, suggesting a correlation between the increase in disease incidence and the increase in temperature and the number of irregular weather events resulting from climate change. However, it cannot be excluded that the increasing availability of latently infected seed tubers has boosted the spread of BR.
Utilization of SSR and cDNA markers for screening known QTLs for late blight (Phytophthora infestans) resistance in potato
(Springer Science+Business Media, 2009) Enrique Ritter; José Ignacio Ruíz de Galarreta; M. Rodríguez Hernández; G. Plata; Leire Barandalla; R. L. López; Isbene Sanchez; Julio Gabriel