scholarly journals First Report of Five Viruses Infecting Potatoes in Tanzania

Plant Disease ◽  
2013 ◽  
Vol 97 (9) ◽  
pp. 1260-1260 ◽  
Author(s):  
E. Chiunga ◽  
J. P. T. Valkonen

Potato (Solanum tuberosum L.) is an increasingly important food and cash crop in Tanzania (3). Potato production is concentrated in the southern highlands and mainly carried out by smallholder farmers. A certification system for seed potatoes does not exist in the country. Currently, there is little information about viruses infecting potatoes in Tanzania. In October through December 2011, occurrence of the most common, globally distributed potato viruses, Potato leaf roll virus (PLRV), Potato virus A (PVA), M (PVM), S (PVS), Y (PVY), and X (PVX) (1), was determined in 219 potato plants in 16 fields ranging from 0.2 to 1 ha. Potato crops, 1 to 3 months old, consisted sometimes of mixtures of varieties identified as Arika, Chekundu, Kagiri, Kiazi, Kikondo, Sasamka, or Tigoni by farmers, but could not be independently confirmed. The fields were located in the regions of Mbeya (Kawetele, Kikondo, Umalia, Uyole) and Rungwe (Mwakaleli) ~100 km apart in the southern highlands. Virus-like symptoms observed in most fields included yellowish-green mosaic, leaf rolling, and veinal necrosis. Symptoms in tubers were not studied. Leaves from 10 symptomatic and three symptomless plants were sampled from each field and tested by double antibody sandwich (DAS)-ELISA (1) at ARI-Uyole. Virus-specific antibodies and negative and positive controls were used according to the supplier's instructions (Science and Advice for Scottish Agriculture, Edinburgh, United Kingdom). PVS and PLRV were detected in 55% and 39% of the samples, respectively, and in all fields sampled. PVX and PVM were found in most fields and in 14% and 5% of the samples, respectively. PVA and PVY were only detected in two localities. Co-infection with PVS and PLRV was detected in 14% of the tested plants. Mixed infections involving three or four viruses were detected in 5% of the plants. A total of 20 samples, which were collected from Uyole and Mwakeleli and found to be ELISA-positive for one or several viruses, were pressed on FTA cards (GE Healthcare, Buckinghamshire, United Kingdom), transported to University of Helsinki, and analyzed by reverse-transcription PCR (2) using virus-specific primers designed to amplify the coat protein (CP) encoding region. All ELISA-positive samples tested positive by reverse transcriptase (RT)-PCR. Four and five samples ELISA-negative for PVX or PVA, respectively, were positive when tested by RT-PCR, suggesting that the actual incidence of these viruses may be higher than detected by DAS-ELISA. The PCR products from three to five samples per virus were sequenced without cloning, which reconfirmed detection of PLRV, PVA, PVS, PVX, and PVM (GenBank Accession Nos. KC866618 through KC866622, respectively) and revealed few if any differences among isolates of the viruses. The CP sequences were compared with viruses from other countries and continents (4). CP similarities suggested that viruses might have been introduced to Tanzania through potato trade or through introducing new cultivars without adequate indexing for viruses. These results suggest the need for the development of virus control schemes in potato crops, including the nascent, domestic certified seed potato production in Mbeya. References: (1) G. Loebenstein et al., eds. Virus and Virus-Like Diseases of Potatoes and Production of Seed Potatoes. Kluwer, Dortrecht, Netherlands, 2001. (2) J. Ndunguru et al. Virol. J. 2:45, 2005. (3) J. Rahko. Potato Value Chain in Tanzania. Univ. Helsinki, Finland, 2012. (4) K. Tamura et al. Mol. Biol. Evol. 28:2731, 2011.

2007 ◽  
Vol 7 ◽  
pp. 1
Author(s):  
S. P. Dhital ◽  
B. M. Sakha ◽  
H. T. Lim

Heat and ribavirin treatments were applied for the elimination of potato leaf roll virus (PLRV) and potato virus Y (PVY) from the potato genotype F 9-99. The explants, rooted young plantlets, cultured on MS medium with and without ribavirin (20 mg l<sup>-1</sup>) were subjected to thermotherapy (35ºC/31ºC, 4 h alternating periods) and room temperature (25ºC) for 30 days. Double antibody sandwich - enzyme linked immunosorbent assay (DAS-ELISA) testing following the therapies revealed that ribavirin alone was enable to eliminate 10% each of PLRV and PVY, whereas along with thermotherapy its efficacy increased to 25% PLRV and 20% PVY elimination. In another experiment, three potato genotypes F 9-99 infected with PLRV and PVY, Gui Valley with PLRV infection and Rose Valley with PVY infection were evaluated. Ribavirin (20 mg l<sup>-1</sup>) and ASA (acetylsalicylic acid) (10<sup>-5</sup> M) were supplemented in liquid culture medium alone or in combination with thermotherapy for three successive cycles of 30-36 days interval. Heat and/or ribavirin suppressed survival and plant height whereas ASA promoted the survival as well as plant height even under heat treatment. After each cycle, the effect of treatment on virus elimination was evaluated by DAS-ELISA. The combined application of ribavirin and ASA with thermotherapy after three cycles of treatment showed up to 47.4% PLRV and 57.9% PVY elimination in F 9-99. In the case of single viral infection of PLRV or PVY the same combined treatment showed up to 58.8% PLRV and 61.1% PVY free plantlets. Virus elimination was also confirmed by transplanting in vitro grown plantlets in a net house and then retesting after 45 days of in vivo growth. This novel technique would be highly efficient for virus elimination within a short duration in diverse genotypes of potato. <i>Nepal Journal of Science and Technology </i> 7 2006


2009 ◽  
Vol 27 (4) ◽  
pp. 490-497 ◽  
Author(s):  
Antônio Carlos de Ávila ◽  
Paulo Eduardo de Melo ◽  
Lindolfo R Leite ◽  
Alice K Inoue-Nagata

As viroses causam rápida degenerescência dos tubérculos-sementes de batata. Em condições tropicais, em que a presença de afídeos vetores é constante e a estrutura das populações de vírus é dinâmica, a pressão das doenças é enorme. Conhecer essa dinâmica é uma ferramenta importante para a sustentabilidade da produção de batata. Realizou-se um levantamento abrangente da ocorrência de viroses em batata no Brasil, além de estudar-se a distribuição das estirpes de Potato virus Y (PVY) associadas ao mosaico da batata. Em 2005 e 2006 foram visitadas lavouras em sete estados brasileiros, coletando-se folíolos com sintomas de viroses (1.256 amostras) e amostras aleatórias (360 amostras). Foi feita também uma estimativa visual da incidência de mosaico e enrolamento-das-folhas em vários dos campos visitados. Das 1.256 amostras suspeitas, 840 apresentaram reação positiva em teste sorológico para PVY (66,9%), 128 para Potato leaf roll virus (PLRV) (10,2%), 79 para Potato virus S (PVS) (6,3%) e nenhuma para Potato virus X (PVX). Os resultados dos testes de detecção por DAS-ELISA, biológico e RT-PCR mostraram a presença quase absoluta do subgrupo necrótico de PVY, em sua maioria PVY NTN. A análise de uma sub-amostragem em todos os municípios visitados confirmou que essa variante está hoje presente nos sete estados visitados. Amostras de PVY NTN foram obtidas das cultivares Asterix, Atlantic, Agata, Achat, Baronesa, Baraka, Bintje, Caesar, Cupido, Marijke, Monalisa, Panda e Vivaldi, que apresentaram diferentes níveis de suscetibilidade. As amostras aleatórias revelaram um quadro muito similar ao encontrado com as amostras sintomáticas. PLRV foi identificado em MG, BA, PR e SC, em várias lavouras de forma muito freqüente. PVS foi identificado nesses mesmos estados e também em SP. PVX foi detectado em apenas uma amostra tomada ao acaso em Serra do Salitre (MG). O contraste entre a avaliação visual dos sintomas e os resultados do teste de detecção por ELISA revelou a possibilidade de infecção latente por PVY em níveis relevantes na cultivar Asterix.


Plant Disease ◽  
2021 ◽  
Author(s):  
Pengcheng Ding ◽  
Dexin Chen ◽  
Haixu Feng ◽  
Jiao Li ◽  
Hui Cao ◽  
...  

Potato is an important crop in Shanxi province located in north-central China. During 2019-2020, 319 potato leaf samples were collected from eight locations distributed in three major potato production areas in Shanxi. Bio-chip detection kit revealed the presence of several potato viruses, and among them potato virus Y (PVY) was the most common one, reaching the incidence of 87.8% of all symptomatic samples. The immuno-captured multiplex reverse transcription (RT)-PCR was used to identify strains for all 280 PVY-positive samples, unveiling 242 samples infected with a single strain of PVY (86.4%) and 38 (13.6%) with a mixed infection. Of samples with a single-strain infection, PVY -SYR-II accounted for 102 (42.1%), followed by PVYN-Wi (33, 13.6%) , PVY -SYR-I (28, 11.6%), 261-4 (22, 9.1%), PVYNTNa (20, 8.3%), PVYNTNb (19, 7.9%), and PVY -SYR-III (18, 7.4%). Seven isolates representing different recombinants were selected for whole genome sequencing. Phylogenetic and recombination analyses confirmed the RT-PCR based strain typing for all seven strains of PVY found in Shanxi. SXKL-12 is the first SYR-III strain from potato reported from China. However, unlike that in other known SYR-III isolates, the region positioned from 1,764 to1,902 nt in SXKL-12 shared the highest sequence identity of 82.2% with an uncharacterized PVY isolate, JL-23, from China. Interestingly, the PVYN-Wi isolate SXZY-40 also possessed a more divergent sequence for the region positioned from 6,156 to 6,276 nt than other N-Wi isolates known to date, sharing the highest identity of 86.6% with an uncharacterized Chinese PVY isolate, JL-11. Pathogenicity analysis of dominant strains PVY -SYR-II and PVYN-Wi in six local popular potato cultivars revealed that Kexin 13, Helan 15 and Jizhangshu 12 were susceptible to these two strains with mild mottling or mosaic symptoms expression, while three cultivars, Jinshu 16, Qingshu 9, Xisen 6 were found fully resistant.


2018 ◽  
Vol 73 (11-12) ◽  
pp. 423-438 ◽  
Author(s):  
Engy E. Abdel Aleem ◽  
Radwa M. Taha ◽  
Faiza A. Fattouh

Abstract Solanum tuberosum (potato) is the second most important vegetable crop in Egypt. It is locally consumed, manufactured or supplied for export to Europe and other Arab countries. Potato is subject to infection by a number of plant viruses, which affect its yield and quality. Potato virus Y (PVY), potato leaf roll virus (PLRV), and Alfalfa mosaic virus (AMV) were detected in major potato-growing areas surveyed. Multiplex-RT-PCR assay was used for the detection of these three viruses in one reaction using three specific primer pairs designed to amplify genomic parts of each virus (1594 bp for PLRV, 795 bp for AMV, 801 bp for PVY). All three viruses were detected in a single reaction mixture in naturally infected field-grown potatoes. Multiplex RT-PCR improved sensitivity necessary for the early detection of infection. Incidence of single, double, or triple infection has been recorded in some locations. Full-length sequencing has been performed for an Egyptian FER isolate of PLRV. Through phylogenetic analysis, it was shown to occupy the same clade with isolate JokerMV10 from Germany. Complete nucleotide sequence of an Egyptian FER isolate of AMV and phylogenetic analysis was also performed; we propose that it is a new distinct strain of AMV belonging to a new subgroup IIC. This is the first complete nucleotide sequence of an Egyptian isolate of AMV. Genetic biodiversity of devastating potato viruses necessitates continuous monitoring of new genetic variants of such viruses.


Author(s):  
Pauline Nyokabi Kamau ◽  
Geoffrey Kingori Gathungu ◽  
Rael Nkatha Mwirigi

This study focused on measuring farm level technical efficiency among smallholder Irish potato farmers in Molo Sub County and its determinants. Descriptive research design was applied. Cross-sectional data was collected through multistage sampling from smallholder Irish potato farmers located in Molo Sub County from April to June 2019. A Stochastic frontier approach assuming a Cobb-Douglas production function was adopted to analyze the level of technical efficiency and explain variations in this technical efficiency across farmers and estimation was done by applying the maximum likelihood method. Mean technical efficiency was 70.7%. The statistically significant variables with respect to the farm inputs were land (0.262), seed (0.629), fertilizer (-0.299) and fungicide (0.131) variables respectively. However, fertilizer variable had negative effects on Irish potato production. Education (-0.061), gender (-0.262), access to extension services (-0.078) and farmer group (-0.217) variables were significant and influenced technical inefficiency negatively.Increase in smallholder farmers’ literacy level, accessibility to extension services and farmer groups may improve Irish potato production technical efficiency. However, gender contribution towards Irish potato production technical efficiency needs a deeper understanding.


Author(s):  
Debora Margareth ◽  
Ida Ayu Astarini ◽  
I Gede Rai Maya Temaja

This study aims to determine the symptoms of virus attacks on potato crops, identification of viruses that attack potato plants in Pancasari village, Bali, efectivity of thermotherapy technique to eliminate in vivo potato. The research was taken using purposive sampling technique and complete random program. Virus symptoms were observed on two potato fields. Serological test employed DAS-ELISA with PVX, PVS, PVY and PLRV antiserum. In vivo elimination virus were done by thermoteraphy in 37°C±1°C (4 days), 34°C±1°C (3 days) on 3 weeks and 33°C±1°C (4 days), 30°C±1°C (3 days) on 2 weeks. Results of the study at Pancasari Village Bali shown varied symptoms on potato leaves, such as mottle, mosaic, malformation, leafroll, witchesbroom. Through serological test, had identified viruses were 11.11% PVX, 55.56% PVS, 80% PVY and 11.11% PLRV which were infected farmer’s potato. In vivo thermotherapy was succeed decreasing PVS and PVY level during 2 weeks on 33°C±1°C (4 days) and 30°C±1°C (3 days).


2011 ◽  
Vol 26 (2) ◽  
pp. 117-127
Author(s):  
Jelena Zindovic

The research was carried out, in the period 2002-2004 in order to determine the presence and distribution of potato viruses at 12 different locations and on 9 different potato varieties grown in Montenegro. The research included collecting of samples in seed potato crops and testing of six economically important potato viruses: Potato leaf roll virus (PLRV), Potato virus Y (PVY), Potato virus X (PVX), Potato virus S (PVS), Potato virus A (PVA) i Potato virus M (PVM). Using the direct enzyme-linked immunosorbent assay (DAS-ELISA) and commercial antisera specific for six potato viruses, it was found that PVY was the most frequent virus during the three-year research period. The second frequent virus was PVS, followed by PVA, PLRV, PVM and PVX. Single and mixed infections were detected, and the most prevalent were the single infections of PVY. Also, in the period 2002-2004, PVY had the highest distribution and the number of present viruses was different at different localities and on different potato varieties. Further investigations were related to detailed characterization of the most prevalent virus (PVY), which is at the same time economically the most important one. Serological characterization of PVY was performed utilizing DAS-ELISA kit with commercial monoclonal antibodies specific for detection of the three strain groups of PVY, and the two strain groups - necrotic (PVYN/PVYNTN) and common (PVYO), were identified. Necrotic strains were prevalent in 2002 and 2004, while in 2003 PVYO was the most frequent strain in virus population. The presence of stipple streak strain (PVYC) was not detected in any of the tested samples.


2000 ◽  
Vol 53 ◽  
pp. 78-82 ◽  
Author(s):  
M.A.W. Stufkens ◽  
D.A.J. Teulon ◽  
D. Nicol ◽  
J.D. Fletcher

The flight patterns of aphid vectors of the potato leaf roll virus were monitored for 18 years with a 75 m high suction trap at Lincoln Canterbury Analysis of the collected samples indicates that latespring and autumn aphid flight peaks vary considerably between seasons and years in their timing magnitude and duration which may have important implications for aphid and virus control in potato crops The potential of a virus forecasting system based on aphid flight monitoring to support potato growers pest management decisions is discussed


Sign in / Sign up

Export Citation Format

Share Document