51
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Wosula EN, Chen W, Fei Z, Legg JP. Unravelling the Genetic Diversity among Cassava Bemisia tabaci Whiteflies Using NextRAD Sequencing. Genome Biol Evol 2018; 9:2958-2973. [PMID: 29096025 PMCID: PMC5714214 DOI: 10.1093/gbe/evx219] [Citation(s) in RCA: 43] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/30/2017] [Indexed: 12/27/2022] Open
Abstract
Bemisia tabaci threatens production of cassava in Africa through vectoring viruses that cause cassava mosaic disease (CMD) and cassava brown streak disease (CBSD). B. tabaci sampled from cassava in eight countries in Africa were genotyped using NextRAD sequencing, and their phylogeny and population genetics were investigated using the resultant single nucleotide polymorphism (SNP) markers. SNP marker data and short sequences of mitochondrial DNA cytochrome oxidase I (mtCOI) obtained from the same insect were compared. Eight genetically distinct groups were identified based on mtCOI, whereas phylogenetic analysis using SNPs identified six major groups, which were further confirmed by PCA and multidimensional analyses. STRUCTURE analysis identified four ancestral B. tabaci populations that have contributed alleles to the six SNP-based groups. Significant gene flows were detected between several of the six SNP-based groups. Evidence of gene flow was strongest for SNP-based groups occurring in central Africa. Comparison of the mtCOI and SNP identities of sampled insects provided a strong indication that hybrid populations are emerging in parts of Africa recently affected by the severe CMD pandemic. This study reveals that mtCOI is not an effective marker at distinguishing cassava-colonizing B. tabaci haplogroups, and that more robust SNP-based multilocus markers should be developed. Significant gene flows between populations could lead to the emergence of haplogroups that might alter the dynamics of cassava virus spread and disease severity in Africa. Continuous monitoring of genetic compositions of whitefly populations should be an essential component in efforts to combat cassava viruses in Africa.
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Affiliation(s)
- Everlyne N Wosula
- International Institute of Tropical Agriculture, Dar es Salaam, Tanzania
| | - Wenbo Chen
- Boyce Thompson Institute, Ithaca, New York
| | - Zhangjun Fei
- Boyce Thompson Institute, Ithaca, New York.,USDA-ARS Robert W. Holley Center for Agriculture and Health, Ithaca, New York
| | - James P Legg
- International Institute of Tropical Agriculture, Dar es Salaam, Tanzania
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52
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Shaw AK, Peace A, Power AG, Bosque-Pérez NA. Vector population growth and condition-dependent movement drive the spread of plant pathogens. Ecology 2018; 98:2145-2157. [PMID: 28555726 DOI: 10.1002/ecy.1907] [Citation(s) in RCA: 41] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/09/2016] [Revised: 04/27/2017] [Accepted: 05/11/2017] [Indexed: 11/08/2022]
Abstract
Plant viruses, often spread by arthropod vectors, impact natural and agricultural ecosystems worldwide. Intuitively, the movement behavior and life history of vectors influence pathogen spread, but the relative contribution of each factor has not been examined. Recent research has highlighted the influence of host infection status on vector behavior and life history. Here, we developed a model to explore how vector traits influence the spread of vector-borne plant viruses. We allowed vector life history (growth rate, carrying capacity) and movement behavior (departure and settlement rates) parameters to be conditional on whether the plant host is infected or healthy and whether the vector is viruliferous (carrying the virus) or not. We ran simulations under a wide range of parameter combinations and quantified the fraction of hosts infected over time. We also ran case studies of the model for Barley yellow dwarf virus, a persistently transmitted virus, and for Potato virus Y, a non-persistently transmitted virus. We quantified the relative importance of each parameter on pathogen spread using Latin hypercube sampling with the statistical partial rank correlation coefficient technique. We found two general types of mechanisms in our model that increased the rate of pathogen spread. First, increasing factors such as vector intrinsic growth rate, carrying capacity, and departure rate from hosts (independent of whether these factors were condition-dependent) led to more vectors moving between hosts, which increased pathogen spread. Second, changing condition-dependent factors such as a vector's preference for settling on a host with a different infection status than itself, and vector tendency to leave a host of the same infection status, led to increased contact between hosts and vectors with different infection statuses, which also increased pathogen spread. Overall, our findings suggest that vector population growth rates had the greatest influence on rates of virus spread, but rates of vector dispersal from infected hosts and from hosts of the same infection status were also very important. Our model highlights the importance of simultaneously considering vector life history and behavior to better understand pathogen spread. Although developed for plant viruses, our model could readily be utilized with other vector-borne pathogen systems.
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Affiliation(s)
- Allison K Shaw
- Department of Ecology, Evolution, and Behavior, University of Minnesota, St. Paul, Minnesota, 55108, USA
| | - Angela Peace
- National Institute for Mathematical and Biological Synthesis, University of Tennessee, Knoxville, Tennessee, 37996, USA.,Department of Mathematics and Statistics, Texas Tech University, Lubbock, Texas, 79409, USA
| | - Alison G Power
- Department of Ecology and Evolutionary Biology, Cornell University, Ithaca, New York, 14853, USA
| | - Nilsa A Bosque-Pérez
- Department of Plant, Soil and Entomological Sciences, University of Idaho, Moscow, Idaho, 83843, USA
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53
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Kalyebi A, Macfadyen S, Parry H, Tay WT, De Barro P, Colvin J. African cassava whitefly, Bemisia tabaci, cassava colonization preferences and control implications. PLoS One 2018; 13:e0204862. [PMID: 30300388 PMCID: PMC6177144 DOI: 10.1371/journal.pone.0204862] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2018] [Accepted: 09/14/2018] [Indexed: 11/19/2022] Open
Abstract
Cassava is a staple food for people across sub-Saharan Africa. Over the last 20 years, there has been an increased frequency of outbreaks and crop damage in this region caused by the cassava-adapted Bemisia tabaci putative species. Little is known about when and why B. tabaci adults move and colonize new cassava crops, especially in farming systems that contain a mixture of cultivar types and plant ages. Here, we assessed experimentally whether the age and variety of cassava affected the density of B. tabaci. We also tested whether the age and variety of the source cassava field affected the variety preference of B. tabaci when they colonized new cassava plants. We placed uninfested potted "sentinel" plants of three cassava varieties (Nam 130, Nase 14, and Njule Red) in source fields containing one of two varieties (Nam 130 or Nase 14) and one of three age classes (young, medium, or old). After two weeks, the numbers of nymphs on the sentinel plants were used as a measure of colonization. Molecular identification revealed that the B. tabaci species was sub-Saharan Africa 1 (SSA1). We found a positive correlation between the density of nymphs on sentinel plants and the density of adults in the source field. The density of nymphs on the sentinels was not significantly related to the age of the source field. Bemisia tabaci adults did not preferentially colonize the sentinel plant of the same variety as the source field. There was a significant interactive effect, however, between the source and sentinel variety that may indicate variability in colonization. We conclude that managing cassava source fields to reduce B. tabaci abundance will be more effective than manipulating nearby varieties. We also suggest that planting a "whitefly sink" variety is unlikely to reduce B. tabaci SSA1 populations unless fields are managed to reduce B. tabaci densities using other integrative approaches.
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Affiliation(s)
- Andrew Kalyebi
- National Crops Resources Research Institute, Kampala, Uganda
- Mikocheni Agricultural Research Institute, Dar es Salaam, Tanzania
| | | | - Hazel Parry
- CSIRO Ecosciences Precinct, Brisbane QLD, Australia
| | - Wee Tek Tay
- CSIRO, Clunies Ross St, Acton, ACT, Australia
| | | | - John Colvin
- Natural Resources Institute, University of Greenwich, Chatham Maritime, Kent, United Kingdom
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54
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Macfadyen S, Paull C, Boykin L, De Barro P, Maruthi M, Otim M, Kalyebi A, Vassão D, Sseruwagi P, Tay W, Delatte H, Seguni Z, Colvin J, Omongo C. Cassava whitefly, Bemisia tabaci (Gennadius) (Hemiptera: Aleyrodidae) in East African farming landscapes: a review of the factors determining abundance. BULLETIN OF ENTOMOLOGICAL RESEARCH 2018; 108:565-582. [PMID: 29433589 PMCID: PMC7672366 DOI: 10.1017/s0007485318000032] [Citation(s) in RCA: 32] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/14/2023]
Abstract
Bemisia tabaci (Gennadius) (Hemiptera: Aleyrodidae) is a pest species complex that causes widespread damage to cassava, a staple food crop for millions of households in East Africa. Species in the complex cause direct feeding damage to cassava and are the vectors of multiple plant viruses. Whilst significant work has gone into developing virus-resistant cassava cultivars, there has been little research effort aimed at understanding the ecology of these insect vectors. Here we assess critically the knowledge base relating to factors that may lead to high population densities of sub-Saharan African (SSA) B. tabaci species in cassava production landscapes of East Africa. We focus first on empirical studies that have examined biotic or abiotic factors that may lead to high populations. We then identify knowledge gaps that need to be filled to deliver sustainable management solutions. We found that whilst many hypotheses have been put forward to explain the increases in abundance witnessed since the early 1990s, there are little published data and these tend to have been collected in a piecemeal manner. The most critical knowledge gaps identified were: (i) understanding how cassava cultivars and alternative host plants impact population dynamics and natural enemies; (ii) the impact of natural enemies in terms of reducing the frequency of outbreaks and (iii) the use and management of insecticides to delay the development of resistance. In addition, there are several fundamental methodologies that need to be developed and deployed in East Africa to address some of the more challenging knowledge gaps.
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Affiliation(s)
- S. Macfadyen
- CSIRO, Clunies Ross St. Acton, ACT, 2601, Australia
- Author for correspondence Phone: +61 (02) 62464432 Fax: +61 (02) 62464094
| | - C. Paull
- CSIRO, Boggo Rd. Dutton Park, QLD, 4001, Australia
| | - L.M. Boykin
- University of Western Australia, School of Molecular Sciences, 35 Stirling Highway, Crawley, WA 6009, Australia
| | - P. De Barro
- CSIRO, Boggo Rd. Dutton Park, QLD, 4001, Australia
| | - M.N. Maruthi
- Natural Resources Institute, University of Greenwich, Chatham Maritime, Kent, ME4 4TB, UK
| | - M. Otim
- National Crops Resources Research Institute, Kampala, Uganda
| | - A. Kalyebi
- National Crops Resources Research Institute, Kampala, Uganda
- Mikocheni Agricultural Research Institute, P.O. Box 6226 Dar es Salaam, Tanzania
| | - D.G. Vassão
- Max Planck Institute for Chemical Ecology, Hans-Knoell Str. 8 D-07745 Jena, Germany
| | - P. Sseruwagi
- Mikocheni Agricultural Research Institute, P.O. Box 6226 Dar es Salaam, Tanzania
| | - W.T. Tay
- CSIRO, Boggo Rd. Dutton Park, QLD, 4001, Australia
| | - H. Delatte
- CIRAD, UMR PVBMT, Saint Pierre, La Réunion 97410-F, France
| | - Z. Seguni
- Mikocheni Agricultural Research Institute, P.O. Box 6226 Dar es Salaam, Tanzania
| | - J. Colvin
- Natural Resources Institute, University of Greenwich, Chatham Maritime, Kent, ME4 4TB, UK
| | - C.A. Omongo
- National Crops Resources Research Institute, Kampala, Uganda
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55
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Jacobson AL, Duffy S, Sseruwagi P. Whitefly-transmitted viruses threatening cassava production in Africa. Curr Opin Virol 2018; 33:167-176. [PMID: 30243102 DOI: 10.1016/j.coviro.2018.08.016] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2018] [Revised: 08/28/2018] [Accepted: 08/31/2018] [Indexed: 10/28/2022]
Abstract
Emerging plant viruses are one of the greatest problems facing crop production worldwide, and have severe consequences in the developing world where subsistence farming is a major source of food production, and knowledge and resources for management are limited. In Africa, evolution of two viral disease complexes, cassava mosaic begomoviruses (CMBs) (Geminiviridae) and cassava brown streak viruses (CBSVs) (Potyviridae), have resulted in severe pandemics that continue to spread and threaten cassava production. Identification of genetically diverse and rapidly evolving CMBs and CBSVs, extensive genetic variation in the vector, Bemisia tabaci (Hemiptera: Aleyrodidae), and numerous secondary endosymbiont profiles that influence vector phenotypes suggest that complex local and regional vector-virus-plant-environment interactions may be driving the evolution and epidemiology of these viruses.
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Affiliation(s)
- Alana Lynn Jacobson
- Department of Entomology and Plant Pathology, Auburn University, 301 Funchess Hall, Auburn, AL 36849, USA.
| | - Siobain Duffy
- Department of Ecology, Evolution, and Natural Resources, Rutgers University, 14 College Farm Rd, New Brunswick, NJ 08901, USA
| | - Peter Sseruwagi
- Mikocheni Agricultural Research Institute, P.O. Box 6226, Dar es Salaam, Tanzania
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56
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Wainaina JM, Ateka E, Makori T, Kehoe MA, Boykin LM. Phylogenomic relationship and evolutionary insights of sweet potato viruses from the western highlands of Kenya. PeerJ 2018; 6:e5254. [PMID: 30038869 PMCID: PMC6054865 DOI: 10.7717/peerj.5254] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2018] [Accepted: 06/24/2018] [Indexed: 11/20/2022] Open
Abstract
Sweet potato is a major food security crop within sub-Saharan Africa where 90% of Africa production occurs. One of the major limitations of sweet potato production are viral infections. In this study, we used a combination of whole genome sequences from a field isolate obtained from Kenya and those available in GenBank. Sequences of four sweet potato viruses: Sweet potato feathery mottle virus (SPFMV), Sweet potato virus C (SPVC), Sweet potato chlorotic stunt virus (SPCSV), Sweet potato chlorotic fleck virus (SPCFV) were obtained from the Kenyan sample. SPFMV sequences both from this study and from GenBank were found to be recombinant. Recombination breakpoints were found within the Nla-Pro, coat protein and P1 genes. The SPCSV, SPVC, and SPCFV viruses from this study were non-recombinant. Bayesian phylogenomic relationships across whole genome trees showed variation in the number of well-supported clades; within SPCSV (RNA1 and RNA2) and SPFMV two well-supported clades (I and II) were resolved. The SPCFV tree resolved three well-supported clades (I-III) while four well-supported clades were resolved in SPVC (I-IV). Similar clades were resolved within the coalescent species trees. However, there were disagreements between the clades resolved in the gene trees compared to those from the whole genome tree and coalescent species trees. However the coat protein gene tree of SPCSV and SPCFV resolved similar clades to the genome and coalescent species tree while this was not the case in SPFMV and SPVC. In addition, we report variation in selective pressure within sites of individual genes across all four viruses; overall all viruses were under purifying selection. We report the first complete genomes of SPFMV, SPVC, SPCFV, and a partial SPCSV from Kenya as a mixed infection in one sample. Our findings provide a snap shot on the evolutionary relationship of sweet potato viruses (SPFMV, SPVC, SPCFV, and SPCSV) from Kenya as well as assessing whether selection pressure has an effect on their evolution.
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Affiliation(s)
- James M. Wainaina
- School of Molecular Sciences/ARC CoE Plant Energy Biology, The University of Western Australia, Crawley, WA, Australia
| | - Elijah Ateka
- Department of Horticulture, Jomo Kenyatta University of Agriculture and Technology, Nairobi, Kenya
| | - Timothy Makori
- Department of Horticulture, Jomo Kenyatta University of Agriculture and Technology, Nairobi, Kenya
| | - Monica A. Kehoe
- Plant Pathology, Department of Primary Industries and Regional Development Diagnostic Laboratory Service, South Perth, WA, Australia
| | - Laura M. Boykin
- School of Molecular Sciences/ARC CoE Plant Energy Biology, The University of Western Australia, Crawley, WA, Australia
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57
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Romba R, Gnankine O, Drabo SF, Tiendrebeogo F, Henri H, Mouton L, Vavre F. Abundance of Bemisia tabaci Gennadius (Hemiptera: Aleyrodidae) and its parasitoids on vegetables and cassava plants in Burkina Faso (West Africa). Ecol Evol 2018; 8:6091-6103. [PMID: 29988460 PMCID: PMC6024141 DOI: 10.1002/ece3.4078] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2017] [Revised: 03/09/2018] [Accepted: 03/24/2018] [Indexed: 02/02/2023] Open
Abstract
The whitefly Bemisia tabaci is a pest of many agricultural and ornamental crops worldwide and particularly in Africa. It is a complex of cryptic species, which is extremely polyphagous with hundreds of host plants identified around the world. Previous surveys in western Africa indicated the presence of two biotypes of the invasive MED species (MED-Q1 and MED-Q3) living in sympatry with the African species SSA and ASL. This situation constitutes one of the rare cases of local coexistence of various genetic entities within the B. tabaci complex. In order to study the dynamics of the distribution and abundance of genetic entities within this community and to identify potential factors that could contribute to coexistence, we sampled B. tabaci populations in Burkina Faso in 2015 and 2016 on various plants, and also their parasitoids. All four genetic entities were still recorded, indicating no exclusion of local species by the MED species. While B. tabaci individuals were found on 55 plant species belonging to eighteen (18) families showing the high polyphagy of this pest, some species/biotypes exhibited higher specificity. Two parasitoid species (Eretmocerus mundus and Encarsia vandrieschei) were also recorded with E. mundus being predominant in most localities and on most plants. Our data indicated that whitefly abundance, diversity, and rate of parasitism varied according to areas, plants, and years, but that parasitism rate was globally highly correlated with whitefly abundance suggesting density dependence. Our results also suggest dynamic variation in the local diversity of B. tabaci species/biotypes from 1 year to the other, specifically with MED-Q1 and ASL species. This work provides relevant information on the nature of plant-B. tabaci-parasitoid interactions in West Africa and identifies that coexistence might be stabilized by niche differentiation for some genetic entities. However, MED-Q1 and ASL show extensive niche overlap, which could ultimately lead to competitive exclusion.
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Affiliation(s)
- Rahim Romba
- Laboratoire d'Entomologie Fondamentale et Appliquée, Unité de Formation et de Recherche en Sciences de la Vie et de la Terre (UFR‐SVT)Université Ouaga I Pr Joseph Ki ZerboOuagadougouBurkina Faso
| | - Olivier Gnankine
- Laboratoire d'Entomologie Fondamentale et Appliquée, Unité de Formation et de Recherche en Sciences de la Vie et de la Terre (UFR‐SVT)Université Ouaga I Pr Joseph Ki ZerboOuagadougouBurkina Faso
| | - Samuel Fogné Drabo
- Laboratoire d'Entomologie Fondamentale et Appliquée, Unité de Formation et de Recherche en Sciences de la Vie et de la Terre (UFR‐SVT)Université Ouaga I Pr Joseph Ki ZerboOuagadougouBurkina Faso
| | | | - Hélène Henri
- Université de LyonUniversité Lyon 1CNRSLaboratoire de Biométrie et Biologie EvolutiveUMR5558VilleurbanneFrance
| | - Laurence Mouton
- Université de LyonUniversité Lyon 1CNRSLaboratoire de Biométrie et Biologie EvolutiveUMR5558VilleurbanneFrance
| | - Fabrice Vavre
- Université de LyonUniversité Lyon 1CNRSLaboratoire de Biométrie et Biologie EvolutiveUMR5558VilleurbanneFrance
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58
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Sseruwagi P, Wainaina J, Ndunguru J, Tumuhimbise R, Tairo F, Guo JY, Vrielink A, Blythe A, Kinene T, De Marchi B, Kehoe MA, Tanz S, Boykin LM. The first transcriptomes from field-collected individual whiteflies ( Bemisia tabaci, Hemiptera: Aleyrodidae): a case study of the endosymbiont composition. Gates Open Res 2018. [PMID: 29608200 DOI: 10.12688/gatesopenres.12783.1] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Background: Bemisia tabaci species ( B. tabaci), or whiteflies, are the world's most devastating insect pests. They cause billions of dollars (US) of damage each year, and are leaving farmers in the developing world food insecure. Currently, all publically available transcriptome data for B. tabaci are generated from pooled samples, which can lead to high heterozygosity and skewed representation of the genetic diversity. The ability to extract enough RNA from a single whitefly has remained elusive due to their small size and technological limitations. Methods: In this study, we optimised a single whitefly RNA extraction procedure, and sequenced the transcriptome of four individual adult Sub-Saharan Africa 1 (SSA1) B. tabaci. Transcriptome sequencing resulted in 39-42 million raw reads. De novo assembly of trimmed reads yielded between 65,000-162,000 Contigs across B. tabaci transcriptomes. Results: Bayesian phylogenetic analysis of mitochondrion cytochrome I oxidase (mtCOI) grouped the four whiteflies within the SSA1 clade. BLASTn searches on the four transcriptomes identified five endosymbionts; the primary endosymbiont Portiera aleyrodidarum and four secondary endosymbionts: Arsenophonus, Wolbachia, Rickettsia, and Cardinium spp. that were predominant across all four SSA1 B. tabaci samples with prevalence levels of between 54.1 to 75%. Amino acid alignments of the NusG gene of P. aleyrodidarum for the SSA1 B. tabaci transcriptomes of samples WF2 and WF2b revealed an eleven amino acid residue deletion that was absent in samples WF1 and WF2a. Comparison of the protein structure of the NusG protein from P. aleyrodidarum in SSA1 with known NusG structures showed the deletion resulted in a shorter D loop. Conclusions: The use of field-collected specimens means time and money will be saved in future studies using single whitefly transcriptomes in monitoring vector and viral interactions. Our method is applicable to any small organism where RNA quantity has limited transcriptome studies.
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Affiliation(s)
- Peter Sseruwagi
- Mikocheni Agriculture Research Institute (MARI), Dar es Salaam, P.O. Box 6226, Tanzania
| | - James Wainaina
- School of Molecular Sciences and Australian Research Council Centre of Excellence in Plant Energy Biology, University of Western Australia, Perth, WA, 6009, Australia
| | - Joseph Ndunguru
- Mikocheni Agriculture Research Institute (MARI), Dar es Salaam, P.O. Box 6226, Tanzania
| | - Robooni Tumuhimbise
- National Agricultural Research Laboratories, P.O. Box 7065, Kampala Kawanda - Senge Rd, Kampala, Uganda
| | - Fred Tairo
- Mikocheni Agriculture Research Institute (MARI), Dar es Salaam, P.O. Box 6226, Tanzania
| | - Jian-Yang Guo
- Ministry of Agriculture Key Laboratory of Agricultural Entomology, Institute of Insect Sciences, Zhejiang University, Hangzhou, 310058, China.,State Key Laboratory for the Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing, 100193, China
| | - Alice Vrielink
- School of Molecular Sciences and Australian Research Council Centre of Excellence in Plant Energy Biology, University of Western Australia, Perth, WA, 6009, Australia
| | - Amanda Blythe
- School of Molecular Sciences and Australian Research Council Centre of Excellence in Plant Energy Biology, University of Western Australia, Perth, WA, 6009, Australia
| | - Tonny Kinene
- School of Molecular Sciences and Australian Research Council Centre of Excellence in Plant Energy Biology, University of Western Australia, Perth, WA, 6009, Australia
| | - Bruno De Marchi
- School of Molecular Sciences and Australian Research Council Centre of Excellence in Plant Energy Biology, University of Western Australia, Perth, WA, 6009, Australia.,Faculdade de Ciências Agronômicas, Universidade Estadual Paulista , Botucatu, Brazil
| | - Monica A Kehoe
- Department of Primary Industries and Regional Development, DPIRD Diagnostic Laboratory Services, South Perth, WA, Australia
| | - Sandra Tanz
- School of Molecular Sciences and Australian Research Council Centre of Excellence in Plant Energy Biology, University of Western Australia, Perth, WA, 6009, Australia
| | - Laura M Boykin
- School of Molecular Sciences and Australian Research Council Centre of Excellence in Plant Energy Biology, University of Western Australia, Perth, WA, 6009, Australia
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59
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Sseruwagi P, Wainaina J, Ndunguru J, Tumuhimbise R, Tairo F, Guo JY, Vrielink A, Blythe A, Kinene T, De Marchi B, Kehoe MA, Tanz S, Boykin LM. The first transcriptomes from field-collected individual whiteflies ( Bemisia tabaci, Hemiptera: Aleyrodidae): a case study of the endosymbiont composition. Gates Open Res 2018; 1:16. [PMID: 29608200 PMCID: PMC5872585 DOI: 10.12688/gatesopenres.12783.3] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/06/2018] [Indexed: 11/23/2022] Open
Abstract
Background: Bemisia tabaci species (
B. tabaci), or whiteflies, are the world’s most devastating insect pests. They cause billions of dollars (US) of damage each year, and are leaving farmers in the developing world food insecure. Currently, all publically available transcriptome data for
B. tabaci are generated from pooled samples, which can lead to high heterozygosity and skewed representation of the genetic diversity. The ability to extract enough RNA from a single whitefly has remained elusive due to their small size and technological limitations. Methods: In this study, we optimised a single whitefly RNA extraction procedure, and sequenced the transcriptome of four individual adult Sub-Saharan Africa 1 (SSA1)
B. tabaci. Transcriptome sequencing resulted in 39-42 million raw reads.
De novo assembly of trimmed reads yielded between 65,000-162,000 Contigs across
B. tabaci transcriptomes. Results: Bayesian phylogenetic analysis of mitochondrion cytochrome I oxidase (mtCOI) grouped the four whiteflies within the SSA1 clade. BLASTn searches on the four transcriptomes identified five endosymbionts; the primary endosymbiont
Portiera aleyrodidarum and four secondary endosymbionts:
Arsenophonus, Wolbachia, Rickettsia, and
Cardinium spp. that were predominant across all four SSA1 B.
tabaci samples with prevalence levels of between 54.1 to 75%. Amino acid alignments of the
NusG gene of
P. aleyrodidarum for the SSA1
B. tabaci transcriptomes of samples WF2 and WF2b revealed an eleven amino acid residue deletion that was absent in samples WF1 and WF2a. Comparison of the protein structure of the
NusG protein from
P. aleyrodidarum in SSA1 with known
NusG structures showed the deletion resulted in a shorter D loop. Conclusions: The use of field-collected specimens means time and money will be saved in future studies using single whitefly transcriptomes in monitoring vector and viral interactions. Our method is applicable to any small organism where RNA quantity has limited transcriptome studies.
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Affiliation(s)
- Peter Sseruwagi
- Mikocheni Agriculture Research Institute (MARI), Dar es Salaam, P.O. Box 6226, Tanzania
| | - James Wainaina
- School of Molecular Sciences and Australian Research Council Centre of Excellence in Plant Energy Biology, University of Western Australia, Perth, WA, 6009, Australia
| | - Joseph Ndunguru
- Mikocheni Agriculture Research Institute (MARI), Dar es Salaam, P.O. Box 6226, Tanzania
| | - Robooni Tumuhimbise
- National Agricultural Research Laboratories, P.O. Box 7065, Kampala Kawanda - Senge Rd, Kampala, Uganda
| | - Fred Tairo
- Mikocheni Agriculture Research Institute (MARI), Dar es Salaam, P.O. Box 6226, Tanzania
| | - Jian-Yang Guo
- Ministry of Agriculture Key Laboratory of Agricultural Entomology, Institute of Insect Sciences, Zhejiang University, Hangzhou, 310058, China.,State Key Laboratory for the Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing, 100193, China
| | - Alice Vrielink
- School of Molecular Sciences and Australian Research Council Centre of Excellence in Plant Energy Biology, University of Western Australia, Perth, WA, 6009, Australia
| | - Amanda Blythe
- School of Molecular Sciences and Australian Research Council Centre of Excellence in Plant Energy Biology, University of Western Australia, Perth, WA, 6009, Australia
| | - Tonny Kinene
- School of Molecular Sciences and Australian Research Council Centre of Excellence in Plant Energy Biology, University of Western Australia, Perth, WA, 6009, Australia
| | - Bruno De Marchi
- School of Molecular Sciences and Australian Research Council Centre of Excellence in Plant Energy Biology, University of Western Australia, Perth, WA, 6009, Australia.,Faculdade de Ciências Agronômicas, Universidade Estadual Paulista , Botucatu, Brazil
| | - Monica A Kehoe
- Department of Primary Industries and Regional Development, DPIRD Diagnostic Laboratory Services, South Perth, WA, Australia
| | - Sandra Tanz
- School of Molecular Sciences and Australian Research Council Centre of Excellence in Plant Energy Biology, University of Western Australia, Perth, WA, 6009, Australia
| | - Laura M Boykin
- School of Molecular Sciences and Australian Research Council Centre of Excellence in Plant Energy Biology, University of Western Australia, Perth, WA, 6009, Australia
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Sseruwagi P, Wainaina J, Ndunguru J, Tumuhimbise R, Tairo F, Guo JY, Vrielink A, Blythe A, Kinene T, De Marchi B, Kehoe MA, Tanz S, Boykin LM. The first transcriptomes from field-collected individual whiteflies (Bemisia tabaci, Hemiptera: Aleyrodidae). Gates Open Res 2018; 1:16. [DOI: 10.12688/gatesopenres.12783.2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 02/02/2018] [Indexed: 11/20/2022] Open
Abstract
Background: Bemisia tabaci species (B. tabaci), or whiteflies, are the world’s most devastating insect pests. They cause billions of dollars (US) of damage each year, and are leaving farmers in the developing world food insecure. Currently, all publically available transcriptome data for B. tabaci are generated from pooled samples, which can lead to high heterozygosity and skewed representation of the genetic diversity. The ability to extract enough RNA from a single whitefly has remained elusive due to their small size and technological limitations. Methods: In this study, we optimised a single whitefly RNA extraction procedure, and sequenced the transcriptome of four individual adult Sub-Saharan Africa 1 (SSA1) B. tabaci. Transcriptome sequencing resulted in 39-42 million raw reads. De novo assembly of trimmed reads yielded between 65,000-162,000 Contigs across B. tabaci transcriptomes. Results: Bayesian phylogenetic analysis of mitochondrion cytochrome I oxidase (mtCOI) grouped the four whiteflies within the SSA1 clade. BLASTn searches on the four transcriptomes identified five endosymbionts; the primary endosymbiont Portiera aleyrodidarum and four secondary endosymbionts: Arsenophonus, Wolbachia, Rickettsia, and Cardinium spp. that were predominant across all four SSA1 B. tabaci samples with prevalence levels of between 54.1 to 75%. Amino acid alignments of the NusG gene of P. aleyrodidarum for the SSA1 B. tabaci transcriptomes of samples WF2 and WF2b revealed an eleven amino acid residue deletion that was absent in samples WF1 and WF2a. Comparison of the protein structure of the NusG protein from P. aleyrodidarum in SSA1 with known NusG structures showed the deletion resulted in a shorter D loop. Conclusions: The use of field-collected specimens means time and money will be saved in future studies using single whitefly transcriptomes in monitoring vector and viral interactions. Our method is applicable to any small organism where RNA quantity has limited transcriptome studies.
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African ancestry of New World, Bemisia tabaci-whitefly species. Sci Rep 2018; 8:2734. [PMID: 29426821 PMCID: PMC5807539 DOI: 10.1038/s41598-018-20956-3] [Citation(s) in RCA: 60] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2016] [Accepted: 01/25/2018] [Indexed: 11/25/2022] Open
Abstract
Bemisia tabaci whitefly species are some of the world’s most devastating agricultural pests and plant-virus disease vectors. Elucidation of the phylogenetic relationships in the group is the basis for understanding their evolution, biogeography, gene-functions and development of novel control technologies. We report here the discovery of five new Sub-Saharan Africa (SSA) B. tabaci putative species, using the partial mitochondrial cytochrome oxidase 1 gene: SSA9, SSA10, SSA11, SSA12 and SSA13. Two of them, SSA10 and SSA11 clustered with the New World species and shared 84.8‒86.5% sequence identities. SSA10 and SSA11 provide new evidence for a close evolutionary link between the Old and New World species. Re-analysis of the evolutionary history of B. tabaci species group indicates that the new African species (SSA10 and SSA11) diverged from the New World clade c. 25 million years ago. The new putative species enable us to: (i) re-evaluate current models of B. tabaci evolution, (ii) recognise increased diversity within this cryptic species group and (iii) re-estimate divergence dates in evolutionary time.
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Anjanappa RB, Mehta D, Okoniewski MJ, Szabelska‐Berȩsewicz A, Gruissem W, Vanderschuren H. Molecular insights into Cassava brown streak virus susceptibility and resistance by profiling of the early host response. MOLECULAR PLANT PATHOLOGY 2018; 19:476-489. [PMID: 28494519 PMCID: PMC6638049 DOI: 10.1111/mpp.12565] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/20/2017] [Revised: 05/02/2017] [Accepted: 05/03/2017] [Indexed: 05/19/2023]
Abstract
Cassava brown streak virus (CBSV) and Ugandan cassava brown streak virus (UCBSV) are responsible for significant cassava yield losses in eastern sub-Saharan Africa. To study the possible mechanisms of plant resistance to CBSVs, we inoculated CBSV-susceptible and CBSV-resistant cassava varieties with a mixed infection of CBSVs using top-cleft grafting. Transcriptome profiling of the two cassava varieties was performed at the earliest time point of full infection (28 days after grafting) in the susceptible scions. The expression of genes encoding proteins in RNA silencing, salicylic acid pathways and callose deposition was altered in the susceptible cassava variety, but transcriptional changes were limited in the resistant variety. In total, the expression of 585 genes was altered in the resistant variety and 1292 in the susceptible variety. Transcriptional changes led to the activation of β-1,3-glucanase enzymatic activity and a reduction in callose deposition in the susceptible cassava variety. Time course analysis also showed that CBSV replication in susceptible cassava induced a strong up-regulation of RDR1, a gene previously reported to be a susceptibility factor in other potyvirus-host pathosystems. The differences in the transcriptional responses to CBSV infection indicated that susceptibility involves the restriction of callose deposition at plasmodesmata. Aniline blue staining of callose deposits also indicated that the resistant variety displays a moderate, but significant, increase in callose deposition at the plasmodesmata. Transcriptome data suggested that resistance does not involve typical antiviral defence responses (i.e. RNA silencing and salicylic acid). A meta-analysis of the current RNA-sequencing (RNA-seq) dataset and selected potyvirus-host and virus-cassava RNA-seq datasets revealed that the conservation of the host response across pathosystems is restricted to genes involved in developmental processes.
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Affiliation(s)
| | - Devang Mehta
- Department of BiologyETH Zurich8092 ZurichSwitzerland
| | - Michal J. Okoniewski
- ID Scientific IT ServicesETH Zurich8092 ZurichSwitzerland
- Functional Genomics Center Zurich8057 ZurichSwitzerland
| | - Alicja Szabelska‐Berȩsewicz
- Functional Genomics Center Zurich8057 ZurichSwitzerland
- Department of Mathematical and Statistical MethodsPoznan University of Life Sciences60‐637 PoznanPoland
| | | | - Hervé Vanderschuren
- Department of BiologyETH Zurich8092 ZurichSwitzerland
- AgroBioChem Department, Gembloux Agro‐Bio TechUniversity of Liège5030 GemblouxBelgium
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Wainaina JM, De Barro P, Kubatko L, Kehoe MA, Harvey J, Karanja D, Boykin LM. Global phylogenetic relationships, population structure and gene flow estimation of Trialeurodes vaporariorum (Greenhouse whitefly). BULLETIN OF ENTOMOLOGICAL RESEARCH 2018; 108:5-13. [PMID: 28532532 DOI: 10.1017/s0007485317000360] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Trialeurodes vaporariorum (Westwood, 1856) (Greenhouse whitefly) is an agricultural pest of global importance. It is associated with damage to plants during feeding and subsequent virus transmission. Yet, global phylogenetic relationships, population structure, and estimation of the rates of gene flow within this whitefly species remain largely unexplored. In this study, we obtained and filtered 227 GenBank records of mitochondrial cytochrome c oxidase I (mtCOI) sequences of T. vaporariorum, across various global locations to obtain a final set of 217 GenBank records. We further amplified and sequenced a ~750 bp fragment of mtCOI from an additional 31 samples collected from Kenya in 2014. Based on a total of 248 mtCOI sequences, we identified 16 haplotypes, with extensive overlap across all countries. Population structure analysis did not suggest population differentiation. Phylogenetic analysis indicated the 2014 Kenyan collection of samples clustered with a single sequence from the Netherlands to form a well-supported clade (denoted clade 1a) nested within the total set of sequences (denoted clade 1). Pairwise distances between sequences show greater sequence divergence between clades than within clades. In addition, analysis using migrate-n gave evidence for recent gene flow between the two groups. Overall, we find that T. vaporariorum forms a single large group, with evidence of further diversification consisting primarily of Kenyan sequences and one sequence from the Netherlands forming a well-supported clade.
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Affiliation(s)
- J M Wainaina
- The University of Western Australia,Australian Research Council Centre of Excellence in Plant Energy Biology and School of Molecular Sciences,Crawley,Perth 6009,Western Australia,Australia
| | - P De Barro
- CSIRO,GPO Box 2583,Brisbane QLD 4001,Australia
| | - L Kubatko
- The Ohio State University 12th Avenue Columbus,Ohio,USA
| | - M A Kehoe
- Departments of Agriculture and Food Western Australia,South Perth WA 6151,Australia
| | - J Harvey
- Feed the Future Innovation Lab for the Reduction of Post-Harvest Loss,Kansas State University,Manhattan,Kansas,USA
| | - D Karanja
- Kenya Agriculture and Livestock Research Organization (KARLO) Box 340-90100,Machakos,Kenya
| | - L M Boykin
- The University of Western Australia,Australian Research Council Centre of Excellence in Plant Energy Biology and School of Molecular Sciences,Crawley,Perth 6009,Western Australia,Australia
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Kayondo SI, Pino Del Carpio D, Lozano R, Ozimati A, Wolfe M, Baguma Y, Gracen V, Offei S, Ferguson M, Kawuki R, Jannink JL. Genome-wide association mapping and genomic prediction for CBSD resistance in Manihot esculenta. Sci Rep 2018; 8:1549. [PMID: 29367617 PMCID: PMC5784162 DOI: 10.1038/s41598-018-19696-1] [Citation(s) in RCA: 50] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2017] [Accepted: 01/08/2018] [Indexed: 12/04/2022] Open
Abstract
Cassava (Manihot esculenta Crantz) is an important security crop that faces severe yield loses due to cassava brown streak disease (CBSD). Motivated by the slow progress of conventional breeding, genetic improvement of cassava is undergoing rapid change due to the implementation of quantitative trait loci mapping, Genome-wide association mapping (GWAS), and genomic selection (GS). In this study, two breeding panels were genotyped for SNP markers using genotyping by sequencing and phenotyped for foliar and CBSD root symptoms at five locations in Uganda. Our GWAS study found two regions associated to CBSD, one on chromosome 4 which co-localizes with a Manihot glaziovii introgression segment and one on chromosome 11, which contains a cluster of nucleotide-binding site-leucine-rich repeat (NBS-LRR) genes. We evaluated the potential of GS to improve CBSD resistance by assessing the accuracy of seven prediction models. Predictive accuracy values varied between CBSD foliar severity traits at 3 months after planting (MAP) (0.27-0.32), 6 MAP (0.40-0.42) and root severity (0.31-0.42). For all traits, Random Forest and reproducing kernel Hilbert spaces regression showed the highest predictive accuracies. Our results provide an insight into the genetics of CBSD resistance to guide CBSD marker-assisted breeding and highlight the potential of GS to improve cassava breeding.
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Affiliation(s)
- Siraj Ismail Kayondo
- National Crop Resources Research Institute, NaCRRI, P.O. Box, 7084, Kampala, Uganda.
- West Africa Center for Crop Improvement, , (WACCI), University of Ghana, Accra, Ghana.
| | - Dunia Pino Del Carpio
- School of Integrative Plant Sciences, Section of Plant Breeding and Genetics, Cornell University, Ithaca, New York, USA
| | - Roberto Lozano
- School of Integrative Plant Sciences, Section of Plant Breeding and Genetics, Cornell University, Ithaca, New York, USA
| | - Alfred Ozimati
- National Crop Resources Research Institute, NaCRRI, P.O. Box, 7084, Kampala, Uganda
- School of Integrative Plant Sciences, Section of Plant Breeding and Genetics, Cornell University, Ithaca, New York, USA
| | - Marnin Wolfe
- School of Integrative Plant Sciences, Section of Plant Breeding and Genetics, Cornell University, Ithaca, New York, USA
| | - Yona Baguma
- National Crop Resources Research Institute, NaCRRI, P.O. Box, 7084, Kampala, Uganda
| | - Vernon Gracen
- West Africa Center for Crop Improvement, , (WACCI), University of Ghana, Accra, Ghana
- School of Integrative Plant Sciences, Section of Plant Breeding and Genetics, Cornell University, Ithaca, New York, USA
| | - Samuel Offei
- West Africa Center for Crop Improvement, , (WACCI), University of Ghana, Accra, Ghana
| | - Morag Ferguson
- International Institute for Tropical Agriculture (IITA), Nairobi, Kenya
| | - Robert Kawuki
- National Crop Resources Research Institute, NaCRRI, P.O. Box, 7084, Kampala, Uganda
| | - Jean-Luc Jannink
- School of Integrative Plant Sciences, Section of Plant Breeding and Genetics, Cornell University, Ithaca, New York, USA
- US Department of Agriculture, Agricultural Research Service (USDA-ARS), Ithaca, New York, USA
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Ghosh S, Bouvaine S, Richardson SCW, Ghanim M, Maruthi MN. Fitness costs associated with infections of secondary endosymbionts in the cassava whitefly species Bemisia tabaci. JOURNAL OF PEST SCIENCE 2018; 91:17-28. [PMID: 29367840 PMCID: PMC5750334 DOI: 10.1007/s10340-017-0910-8] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/29/2017] [Revised: 07/31/2017] [Accepted: 08/12/2017] [Indexed: 05/13/2023]
Abstract
We investigated the dual effects of bacterial infections and diseased cassava plants on the fitness and biology of the Bemisia tabaci infesting cassava in Africa. Isofemale B. tabaci colonies of sub-Saharan Africa 1-subgroup 3 (SSA1-SG3), infected with two secondary endosymbiotic bacteria Arsenophonus and Rickettsia (AR+) and those free of AR infections (AR-), were compared for fitness parameters on healthy and East African cassava mosaic virus-Uganda variant (EACMV-UG)-infected cassava plants. The whitefly fecundity and nymph development was not affected by bacterial infections or the infection of cassava by the virus. However, emergence of adults from nymphs was 50 and 17% higher by AR- on healthy and virus-infected plants, respectively, than AR+ flies. Development time of adults also was 10 days longer in AR+ than AR-. The whiteflies were further compared for acquisition and retention of EACMV-UG. Higher proportion of AR- acquired (91.8%) and retained (87.6%) the virus than AR+ (71.8, 61.2%, respectively). Similarly, the AR- flies retained higher quantities of virus (~ninefold more) than AR+. These results indicated that bacteria-free whiteflies were superior and better transmitters of EACMV-UG, as they had higher adult emergence, quicker life cycle and better virus retention abilities than those infected with bacteria.
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Affiliation(s)
- Saptarshi Ghosh
- Natural Resources Institute, University of Greenwich, Central Avenue, Chatham Maritime, Kent, ME4 4TB UK
| | - Sophie Bouvaine
- Natural Resources Institute, University of Greenwich, Central Avenue, Chatham Maritime, Kent, ME4 4TB UK
| | - Simon C. W. Richardson
- Faculty of Engineering and Science, University of Greenwich, Medway Campus, Central Avenue, Chatham Maritime, Kent, ME4 4TB UK
| | - Murad Ghanim
- Volcani Center, ARO, HaMaccabim Road 68, PO Box 15159, 7528809 Rishon Le Tsiyon, Israel
| | - M. N. Maruthi
- Natural Resources Institute, University of Greenwich, Central Avenue, Chatham Maritime, Kent, ME4 4TB UK
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Szyniszewska AM, Busungu C, Boni SB, Shirima R, Bouwmeester H, Legg JP. Spatial Analysis of Temporal Changes in the Pandemic of Severe Cassava Mosaic Disease in Northwestern Tanzania. PHYTOPATHOLOGY 2017; 107:1229-1242. [PMID: 28714353 DOI: 10.1094/phyto-03-17-0105-fi] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
To improve understanding of the dynamics of the cassava mosaic disease (CMD) pandemic front, geospatial approaches were applied to the analysis of 3 years' data obtained from a 2-by-2° (approximately 222-by-222 km) area of northwestern Tanzania. In total, 80 farmers' fields were assessed in each of 2009, 2010, and 2011, with 20 evenly distributed fields per 1-by-1° quadrant. CMD-associated variables (CMD incidence, CMD severity, vector-borne CMD infection, and vector abundance) increased in magnitude from 2009 to 2010 but showed little change from 2010 to 2011. Increases occurred primarily in the two westernmost quadrants of the study area. A pandemic "front" was defined by determining the values of CMD incidence and whitefly abundance where predicted disease gradients were greatest. The pandemic-associated virus (East African cassava mosaic virus-Uganda) and vector genotype (Bemisia tabaci sub-Saharan Africa 1-subgroup 1) were both present within the area bounded by the CMD incidence front but both also occurred ahead of the front. The average speed and direction of movement of the CMD incidence front (22.9 km/year; southeast) and whitefly abundance front (46.6 km/year; southeast) were calculated, and production losses due to CMD were estimated to range from US$4.3 million to 12.2 million.
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Affiliation(s)
- A M Szyniszewska
- First author: Rothamsted Research, Harpenden, Hertfordshire, AL5 2JQ, United Kingdom; second author: United Graduate School of Agricultural Sciences, Kagoshima University, 1-21-24 Korimoto, Kagoshima 890-0065, Japan; third author: PO Box 21026, Dar es Salaam, Tanzania; fourth and sixth authors: International Institute of Tropical Agriculture, PO Box 34441, Dar es Salaam, Tanzania; and fifth author: Geospace, Roseboomlaan 38, 6717 ZB Ede, The Netherlands
| | - C Busungu
- First author: Rothamsted Research, Harpenden, Hertfordshire, AL5 2JQ, United Kingdom; second author: United Graduate School of Agricultural Sciences, Kagoshima University, 1-21-24 Korimoto, Kagoshima 890-0065, Japan; third author: PO Box 21026, Dar es Salaam, Tanzania; fourth and sixth authors: International Institute of Tropical Agriculture, PO Box 34441, Dar es Salaam, Tanzania; and fifth author: Geospace, Roseboomlaan 38, 6717 ZB Ede, The Netherlands
| | - S B Boni
- First author: Rothamsted Research, Harpenden, Hertfordshire, AL5 2JQ, United Kingdom; second author: United Graduate School of Agricultural Sciences, Kagoshima University, 1-21-24 Korimoto, Kagoshima 890-0065, Japan; third author: PO Box 21026, Dar es Salaam, Tanzania; fourth and sixth authors: International Institute of Tropical Agriculture, PO Box 34441, Dar es Salaam, Tanzania; and fifth author: Geospace, Roseboomlaan 38, 6717 ZB Ede, The Netherlands
| | - R Shirima
- First author: Rothamsted Research, Harpenden, Hertfordshire, AL5 2JQ, United Kingdom; second author: United Graduate School of Agricultural Sciences, Kagoshima University, 1-21-24 Korimoto, Kagoshima 890-0065, Japan; third author: PO Box 21026, Dar es Salaam, Tanzania; fourth and sixth authors: International Institute of Tropical Agriculture, PO Box 34441, Dar es Salaam, Tanzania; and fifth author: Geospace, Roseboomlaan 38, 6717 ZB Ede, The Netherlands
| | - H Bouwmeester
- First author: Rothamsted Research, Harpenden, Hertfordshire, AL5 2JQ, United Kingdom; second author: United Graduate School of Agricultural Sciences, Kagoshima University, 1-21-24 Korimoto, Kagoshima 890-0065, Japan; third author: PO Box 21026, Dar es Salaam, Tanzania; fourth and sixth authors: International Institute of Tropical Agriculture, PO Box 34441, Dar es Salaam, Tanzania; and fifth author: Geospace, Roseboomlaan 38, 6717 ZB Ede, The Netherlands
| | - J P Legg
- First author: Rothamsted Research, Harpenden, Hertfordshire, AL5 2JQ, United Kingdom; second author: United Graduate School of Agricultural Sciences, Kagoshima University, 1-21-24 Korimoto, Kagoshima 890-0065, Japan; third author: PO Box 21026, Dar es Salaam, Tanzania; fourth and sixth authors: International Institute of Tropical Agriculture, PO Box 34441, Dar es Salaam, Tanzania; and fifth author: Geospace, Roseboomlaan 38, 6717 ZB Ede, The Netherlands
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Legg J, Ndalahwa M, Yabeja J, Ndyetabula I, Bouwmeester H, Shirima R, Mtunda K. Community phytosanitation to manage cassava brown streak disease. Virus Res 2017; 241:236-253. [PMID: 28487059 PMCID: PMC5669585 DOI: 10.1016/j.virusres.2017.04.020] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2017] [Revised: 04/05/2017] [Accepted: 04/18/2017] [Indexed: 02/04/2023]
Abstract
Cassava viruses are the major biotic constraint to cassava production in Africa. Community-wide action to manage them has not been attempted since a successful cassava mosaic disease control programme in the 1930s/40s in Uganda. A pilot initiative to investigate the effectiveness of community phytosanitation for managing cassava brown streak disease (CBSD) was implemented from 2013 to 2016 in two communities in coastal (Mkuranga) and north-western (Chato) Tanzania. CBSD incidence in local varieties at the outset was >90%, which was typical of severely affected regions of Tanzania. Following sensitization and monitoring by locally-recruited taskforces, there was effective community-wide compliance with the initial requirement to replace local CBSD-infected material with newly-introduced disease-free planting material of improved varieties. The transition was also supported by the free provision of additional seed sources, including maize, sweet potato, beans and cowpeas. Progress of the initiative was followed in randomly-selected monitoring fields in each of the two locations. Community phytosanitation in both target areas produced an area-wide reduction in CBSD incidence, which was sustained over the duration of the programme. In Chato, maximum CBSD incidence was 39.1% in the third season, in comparison with an incidence of >60% after a single season in a control community where disease-free planting material was introduced in the absence of community phytosanitation. Kriging and geospatial analysis demonstrated that inoculum pressure, which was a function of vector abundance and the number of CBSD-infected plants surrounding monitored fields, was a strong determinant of the pattern of CBSD development in monitored fields. In the first year, farmers achieved yield increases with the new varieties relative to the local variety baseline of 94% in Chato (north-west) and 124% in Mkuranga (coast). Yield benefits of the new material were retained up to the final season in each location. The new variety (Mkombozi) introduced under community phytosanitation conditions in Chato yielded 86% more than the same variety from the same source planted in the no-phytosanitation control location. Although there was an 81% reduction in CBSD incidence in the new variety Kiroba introduced under community phytosanitation compared to control conditions in Mkuranga, there was no concomitant yield increase. Variety Kiroba is known to be tolerant to the effects of CBSD, and tuberous roots of infected plants are frequently asymptomatic. Community phytosanitation has the potential to deliver area-wide and sustained reductions in the incidence of CBSD, which also provide significant productivity gains for growers, particularly where introduced varieties do not have high levels of resistant/tolerance to CBSD. The approach should therefore be considered as a potential component for integrated cassava virus management programmes, particularly where new cassava plantations are being established in areas severely affected by CBSD.
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Affiliation(s)
- James Legg
- International Institute of Tropical Agriculture, PO Box 34441, Dar es Salaam, Tanzania.
| | - Mathias Ndalahwa
- International Institute of Tropical Agriculture, PO Box 34441, Dar es Salaam, Tanzania
| | - Juma Yabeja
- International Institute of Tropical Agriculture, PO Box 34441, Dar es Salaam, Tanzania
| | | | | | - Rudolph Shirima
- International Institute of Tropical Agriculture, PO Box 34441, Dar es Salaam, Tanzania
| | - Kiddo Mtunda
- Sugarcane Agricultural Research Institute, PO Box 30031, Kibaha, Tanzania
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Tocko-Marabena BK, Silla S, Simiand C, Zinga I, Legg J, Reynaud B, Delatte H. Genetic diversity of Bemisia tabaci species colonizing cassava in Central African Republic characterized by analysis of cytochrome c oxidase subunit I. PLoS One 2017; 12:e0182749. [PMID: 28813463 PMCID: PMC5557543 DOI: 10.1371/journal.pone.0182749] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2017] [Accepted: 07/23/2017] [Indexed: 12/03/2022] Open
Abstract
After 2007, upsurges of whiteflies on cassava plants and high incidences of cassava diseases were observed in Central African Republic. This recent upsurge in the abundance of Bemisia tabaci (Gennadius) (Hemiptera: Aleyrodidae) was directly linked to serious damage to cassava crops resulting from spread of whitefly-borne cassava mosaic geminiviruses (CMGs). There is currently very little information describing whitefly populations on cassava and associated crops in Central African Republic. The current study aimed to address this gap, and to determine whether the increasing damage associated with B. tabaci whiteflies was the consequence of a new invasion, or an upsurge of a local population. The molecular genetic identification and phylogenetic relationships of 898 B. tabaci adult individuals collected from representative locations (54) throughout CAR were determined based on their mitochondrial cytochrome oxidase I sequences (mtCOI). Field and ecological data were also collected from each site, including whitefly abundance, CMD incidence, host plants colonized by B. tabaci and agro-ecological zone. Phylogenetic analysis of the whitefly mtCOI sequences indicated that SSA1 (-SG1, -SG2), SSA3, MED, MEAM1 and Indian Ocean (IO) putative species occur in CAR. One specific haplotype of SSA1-SG1 (SSA1-SG1-P18F5) predominated on most cassava plants and at the majority of sites. This haplotype was identical to the SSA1-SG1 Mukono8-4 (KM377961) haplotype that was recorded from Uganda but that also occurs widely in CMD pandemic-affected areas of East Africa. These results suggest that the SSA1-SG1-P18F5 haplotype occurring in CAR represents a recent invasive population, and that it is the likely cause of the increased spread and severity of CMD in CAR. Furthermore, the high mtDNA sequence diversity observed for SSA1 and its broad presence on all sites and host plants sampled suggest that this genetic group was the dominant resident species even before the arrival of this new invasive haplotype.
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Affiliation(s)
- Brice Kette Tocko-Marabena
- Laboratoire des Sciences Biologiques et Agronomique pour le Développement (LBSAD), Université de Bangui, Bangui, Centrafrique
- CIRAD, UMR PVBMT, Pôle de Protection des Plantes, Saint-Pierre, Île de la Réunion, France
- Université de la Réunion, UMR PVBMT, Pôle de Protection des Plantes, Saint-Pierre, Île de la Réunion, France
| | - Semballa Silla
- Laboratoire des Sciences Biologiques et Agronomique pour le Développement (LBSAD), Université de Bangui, Bangui, Centrafrique
| | - Christophe Simiand
- CIRAD, UMR PVBMT, Pôle de Protection des Plantes, Saint-Pierre, Île de la Réunion, France
| | - Innocent Zinga
- Laboratoire des Sciences Biologiques et Agronomique pour le Développement (LBSAD), Université de Bangui, Bangui, Centrafrique
| | | | - Bernard Reynaud
- Université de la Réunion, UMR PVBMT, Pôle de Protection des Plantes, Saint-Pierre, Île de la Réunion, France
| | - Helene Delatte
- CIRAD, UMR PVBMT, Pôle de Protection des Plantes, Saint-Pierre, Île de la Réunion, France
- * E-mail:
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Rahman MU, Khan AQ, Rahmat Z, Iqbal MA, Zafar Y. Genetics and Genomics of Cotton Leaf Curl Disease, Its Viral Causal Agents and Whitefly Vector: A Way Forward to Sustain Cotton Fiber Security. FRONTIERS IN PLANT SCIENCE 2017; 8:1157. [PMID: 28725230 PMCID: PMC5495822 DOI: 10.3389/fpls.2017.01157] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 02/04/2017] [Accepted: 06/15/2017] [Indexed: 06/07/2023]
Abstract
Cotton leaf curl disease (CLCuD) after its first epidemic in 1912 in Nigeria, has spread to different cotton growing countries including United States, Pakistan, India, and China. The disease is of viral origin-transmitted by the whitefly Bemisia tabaci, which is difficult to control because of the prevalence of multiple virulent viral strains or related species. The problem is further complicated as the CLCuD causing virus complex has a higher recombination rate. The availability of alternate host crops like tomato, okra, etc., and practicing mixed type farming system have further exaggerated the situation by adding synergy to the evolution of new viral strains and vectors. Efforts to control this disease using host plant resistance remained successful using two gene based-resistance that was broken by the evolution of new resistance breaking strain called Burewala virus. Development of transgenic cotton using both pathogen and non-pathogenic derived approaches are in progress. In future, screening for new forms of host resistance, use of DNA markers for the rapid incorporation of resistance into adapted cultivars overlaid with transgenics and using genome editing by CRISPR/Cas system would be instrumental in adding multiple layers of defense to control the disease-thus cotton fiber production will be sustained.
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Affiliation(s)
- Mehboob-ur- Rahman
- National Institute for Biotechnology and Genetic EngineeringFaisalabad, Pakistan
| | - Ali Q. Khan
- National Institute for Biotechnology and Genetic EngineeringFaisalabad, Pakistan
| | - Zainab Rahmat
- National Institute for Biotechnology and Genetic EngineeringFaisalabad, Pakistan
| | - Muhammad A. Iqbal
- National Institute for Biotechnology and Genetic EngineeringFaisalabad, Pakistan
| | - Yusuf Zafar
- Pakistan Agricultural Research CouncilIslamabad, Pakistan
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Boni SB, Rugumamu CP, Gerling D, Sagary Nokoe K, Legg JP. Interactions Between Cassava Mosaic Geminiviruses and Their Vector, Bemisia tabaci (Hemiptera: Aleyrodidae). JOURNAL OF ECONOMIC ENTOMOLOGY 2017; 110:884-892. [PMID: 28431093 DOI: 10.1093/jee/tox064] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/12/2016] [Indexed: 06/07/2023]
Abstract
The sweetpotato whitefly, Bemisia tabaci (Gennadius) is the vector of the cassava mosaic geminiviruses (CMGs) that cause cassava mosaic disease (CMD). Synergistic interactions between B. tabaci and CMGs have been hypothesized as a cause of whitefly "super-abundance," which has been a key factor behind the spread of the severe CMD pandemic through East and Central Africa. The current study investigated this hypothesis by conducting experiments with CMD-susceptible cassava varieties infected with different CMGs in both the north-western Lake Zone region (pandemic affected) and the eastern Coast Zone where CMD is less severe. Male and female pairs of B. tabaci were placed in clip cages for 48 h on plants of three cassava varieties at each of the two locations. There were significantly more eggs laid on CMG-infected than on CMG-free plants in the Lake Zone, whereas in Coast Zone, there were no significant differences. There were no significant differences in proportions, mortality, and development duration of immature stages of B. tabaci among virus states and cassava variety in the two locations. The overall number of eggs was significantly higher with longer development duration of the immature stages in the Lake than in the Coast Zone, whereas mortality was significantly higher in the Coast than in the Lake Zone. Based on these results, it is concluded that there was no net positive synergistic interaction between CMGs and B. tabaci for either lowland coastal or mid-altitude inland populations. Consequently, other factors seem more likely to be the cause of the "super-abundance," and require further investigation.
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Affiliation(s)
- Simon B Boni
- International Institute of Tropical Agriculture (IITA), Plot 25, Mwenge Coca-Cola Road, Mikocheni B, P. O. Box 34441, Dar es Salaam, Tanzania, ( ; )
- Current address: P. O. Box 21026, Dar es Salaam, Tanzania
| | - Costancia P Rugumamu
- Department of Zoology and Wildlife Conservation, University of Dar es Salaam, P. O. Box 35064, Dar es Salaam, Tanzania,
| | - Dan Gerling
- Department of Zoology, Tel Aviv University, Ramat Aviv 69978, Israel
| | - K Sagary Nokoe
- University of Energy & Natural Resources, P. O. Box 214, Sunyani, B/A Ghana
| | - James P Legg
- International Institute of Tropical Agriculture (IITA), Plot 25, Mwenge Coca-Cola Road, Mikocheni B, P. O. Box 34441, Dar es Salaam, Tanzania, ( ; )
- Corresponding author:
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71
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Yonow T, Kriticos DJ, Ota N. The potential distribution of cassava mealybug (Phenacoccus manihoti), a threat to food security for the poor. PLoS One 2017; 12:e0173265. [PMID: 28296903 PMCID: PMC5351876 DOI: 10.1371/journal.pone.0173265] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2016] [Accepted: 12/15/2016] [Indexed: 11/25/2022] Open
Abstract
The cassava mealybug is a clear and present threat to the food security and livelihoods of some of the world's most impoverished citizens. Niche models, such as CLIMEX, are useful tools to indicate where and when such threats may extend, and can assist with planning for biosecurity and the management of pest invasions. They can also contribute to bioeconomic analyses that underpin the allocation of resources to alleviate poverty. Because species can invade and establish in areas with climates that are different from those that are found in their native range, it is essential to define robust range-limiting mechanisms in niche models. To avoid spurious results when applied to novel climates, it is necessary to employ cross-validation techniques spanning different knowledge domains (e.g., distribution data, experimental results, phenological observations). We build upon and update a CLIMEX niche model by Parsa et al. (PloS ONE 7: e47675), correcting inconsistent parameters and re-fitting it based on a careful examination of geographical distribution data and relevant literature. Further, we consider the role of irrigation, the known distribution of cassava production and a targeted review of satellite imagery to refine, validate and interpret our model and results. In so doing, we bring new insights into the potential spread of this invasive insect, enabling us to identify potential bio-security threats and biological control opportunities. The fit of the revised model is improved, particularly in relation to the wet and dry limits to establishment, and the parameter values are biologically plausible and accord with published scientific literature.
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Affiliation(s)
- Tania Yonow
- HarvestChoice, InSTePP, University of Minnesota, St. Paul, MN, United States of America
- CSIRO, Canberra ACT, Australia
| | - Darren J. Kriticos
- HarvestChoice, InSTePP, University of Minnesota, St. Paul, MN, United States of America
- CSIRO, Canberra ACT, Australia
- The University of Queensland, School of Biological Sciences, St. Lucia, QLD, Australia
- * E-mail:
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72
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Manani DM, Ateka EM, Nyanjom SRG, Boykin LM. Phylogenetic Relationships among Whiteflies in the Bemisia tabaci (Gennadius) Species Complex from Major Cassava Growing Areas in Kenya. INSECTS 2017; 8:E25. [PMID: 28264479 PMCID: PMC5371953 DOI: 10.3390/insects8010025] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/26/2016] [Revised: 02/07/2017] [Accepted: 02/15/2017] [Indexed: 11/16/2022]
Abstract
Whiteflies, Bemisia tabaci (Gennadius) are major insect pests that affect many crops such as cassava, tomato, beans, cotton, cucurbits, potato, sweet potato, and ornamental crops. Bemisia tabaci transmits viral diseases, namely cassava mosaic and cassava brown streak diseases, which are the main constraints to cassava production, causing huge losses to many small-scale farmers. The aim of this work was to determine the phylogenetic relationships among Bemisia tabaci species in major cassava growing areas of Kenya. Surveys were carried out between 2013 and 2015 in major cassava growing areas (Western, Nyanza, Eastern, and Coast regions), for cassava mosaic disease (CMD) and cassava brown streak disease (CBSD). Mitochondrial cytochrome oxidase I (mtCOI-DNA) was used to determine the genetic diversity of B. tabaci. Phylogenetic trees were constructed using Bayesian methods to understand the genetic diversity across the study regions. Phylogenetic analysis revealed two B. tabaci species present in Kenya, sub-Saharan Africa 1 and 2 comprising five distinct clades (A-E) with percent sequence similarity ranging from 97.7 % to 99.5%. Clades B, C, D, and E are predominantly distributed in the Western and Nyanza regions of Kenya whereas clade B is dominantly found along the coast, the eastern region, and parts of Nyanza. Our B. tabaci clade A groups with sub-Saharan Africa 2-(SSA2) recorded a percent sequence similarity of 99.5%. In this study, we also report the identification of SSA2 after a 15 year absence in Kenya. The SSA2 species associated with CMD has been found in the Western region of Kenya bordering Uganda. More information is needed to determine if these species are differentially involved in the epidemiology of the cassava viruses.
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Affiliation(s)
- Duke M Manani
- Department of Biochemistry, Jomo Kenyatta University of Agriculture and Technology, Nairobi P.O. Box 62000-00200, Kenya.
| | - Elijah M Ateka
- Department of Horticulture, Jomo Kenyatta University of Agriculture and Technology, Nairobi P.O. Box 62000-00200, Kenya.
| | - Steven R G Nyanjom
- Department of Biochemistry, Jomo Kenyatta University of Agriculture and Technology, Nairobi P.O. Box 62000-00200, Kenya.
| | - Laura M Boykin
- Australian Research Council Centre of Excellence in Plant Energy Biology, The University of Western Australia, Crawley, WA 6009, Australia.
- School of Molecular Sciences, The University of Western Australia, Crawley, WA 6009, Australia.
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73
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Wagaba H, Beyene G, Aleu J, Odipio J, Okao-Okuja G, Chauhan RD, Munga T, Obiero H, Halsey ME, Ilyas M, Raymond P, Bua A, Taylor NJ, Miano D, Alicai T. Field Level RNAi-Mediated Resistance to Cassava Brown Streak Disease across Multiple Cropping Cycles and Diverse East African Agro-Ecological Locations. FRONTIERS IN PLANT SCIENCE 2017; 7:2060. [PMID: 28127301 PMCID: PMC5226948 DOI: 10.3389/fpls.2016.02060] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/21/2016] [Accepted: 12/23/2016] [Indexed: 05/24/2023]
Abstract
Cassava brown streak disease (CBSD) presents a serious threat to cassava production in East and Central Africa. Currently, no cultivars with high levels of resistance to CBSD are available to farmers. Transgenic RNAi technology was employed to combat CBSD by fusing coat protein (CP) sequences from Ugandan cassava brown streak virus (UCBSV) and Cassava brown streak virus (CBSV) to create an inverted repeat construct (p5001) driven by the constitutive Cassava vein mosaic virus promoter. Twenty-five plant lines of cultivar TME 204 expressing varying levels of small interfering RNAs (siRNAs) were established in confined field trials (CFTs) in Uganda and Kenya. Within an initial CFT at Namulonge, Uganda, non-transgenic TME 204 plants developed foliar and storage root CBSD incidences at 96-100% by 12 months after planting. In contrast, 16 of the 25 p5001 transgenic lines showed no foliar symptoms and had less than 8% of their storage roots symptomatic for CBSD. A direct positive correlation was seen between levels of resistance to CBSD and expression of transgenic CP-derived siRNAs. A subsequent CFT was established at Namulonge using stem cuttings from the initial trial. All transgenic lines established remained asymptomatic for CBSD, while 98% of the non-transgenic TME 204 stake-derived plants developed storage roots symptomatic for CBSD. Similarly, very high levels of resistance to CBSD were demonstrated by TME 204 p5001 RNAi lines grown within a CFT over a full cropping cycle at Mtwapa, coastal Kenya. Sequence analysis of CBSD causal viruses present at the trial sites showed that the transgenic lines were exposed to both CBSV and UCBSV, and that the sequenced isolates shared >90% CP identity with transgenic CP sequences expressed by the p5001 inverted repeat expression cassette. These results demonstrate very high levels of field resistance to CBSD conferred by the p5001 RNAi construct at diverse agro-ecological locations, and across the vegetative cropping cycle.
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Affiliation(s)
- Henry Wagaba
- National Crops Resources Research InstituteKampala, Uganda
| | - Getu Beyene
- Donald Danforth Plant Science CenterSt. Louis, MO, USA
| | - Jude Aleu
- National Crops Resources Research InstituteKampala, Uganda
| | - John Odipio
- National Crops Resources Research InstituteKampala, Uganda
- Donald Danforth Plant Science CenterSt. Louis, MO, USA
| | | | | | - Theresia Munga
- Kenya Agricultural and Livestock Research OrganizationNairobi, Kenya
| | | | | | | | | | - Anton Bua
- National Crops Resources Research InstituteKampala, Uganda
| | | | - Douglas Miano
- Department of Plant Science and Crop Protection, University of NairobiNairobi, Kenya
| | - Titus Alicai
- National Crops Resources Research InstituteKampala, Uganda
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Kaur N, Hasegawa DK, Ling KS, Wintermantel WM. Application of Genomics for Understanding Plant Virus-Insect Vector Interactions and Insect Vector Control. PHYTOPATHOLOGY 2016; 106:1213-1222. [PMID: 27442532 DOI: 10.1094/phyto-02-16-0111-fi] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
The relationships between plant viruses and their vectors have evolved over the millennia, and yet, studies on viruses began <150 years ago and investigations into the virus and vector interactions even more recently. The advent of next generation sequencing, including rapid genome and transcriptome analysis, methods for evaluation of small RNAs, and the related disciplines of proteomics and metabolomics offer a significant shift in the ability to elucidate molecular mechanisms involved in virus infection and transmission by insect vectors. Genomic technologies offer an unprecedented opportunity to examine the response of insect vectors to the presence of ingested viruses through gene expression changes and altered biochemical pathways. This review focuses on the interactions between viruses and their whitefly or thrips vectors and on potential applications of genomics-driven control of the insect vectors. Recent studies have evaluated gene expression in vectors during feeding on plants infected with begomoviruses, criniviruses, and tospoviruses, which exhibit very different types of virus-vector interactions. These studies demonstrate the advantages of genomics and the potential complementary studies that rapidly advance our understanding of the biology of virus transmission by insect vectors and offer additional opportunities to design novel genetic strategies to manage insect vectors and the viruses they transmit.
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Affiliation(s)
- Navneet Kaur
- First and fourth authors: USDA-ARS, Crop Improvement and Protection Research, Salinas, CA 93905; second author: USDA-ARS, U.S. Vegetable Laboratory, Charleston, SC 29414; Boyce Thompson Institute, Cornell University, Ithaca, NY 14853; and third author: USDA-ARS, U.S. Vegetable Laboratory, Charleston, SC 29414
| | - Daniel K Hasegawa
- First and fourth authors: USDA-ARS, Crop Improvement and Protection Research, Salinas, CA 93905; second author: USDA-ARS, U.S. Vegetable Laboratory, Charleston, SC 29414; Boyce Thompson Institute, Cornell University, Ithaca, NY 14853; and third author: USDA-ARS, U.S. Vegetable Laboratory, Charleston, SC 29414
| | - Kai-Shu Ling
- First and fourth authors: USDA-ARS, Crop Improvement and Protection Research, Salinas, CA 93905; second author: USDA-ARS, U.S. Vegetable Laboratory, Charleston, SC 29414; Boyce Thompson Institute, Cornell University, Ithaca, NY 14853; and third author: USDA-ARS, U.S. Vegetable Laboratory, Charleston, SC 29414
| | - William M Wintermantel
- First and fourth authors: USDA-ARS, Crop Improvement and Protection Research, Salinas, CA 93905; second author: USDA-ARS, U.S. Vegetable Laboratory, Charleston, SC 29414; Boyce Thompson Institute, Cornell University, Ithaca, NY 14853; and third author: USDA-ARS, U.S. Vegetable Laboratory, Charleston, SC 29414
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75
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Ndunguru J, Sseruwagi P, Tairo F, Stomeo F, Maina S, Djinkeng A, Kehoe M, Boykin LM. Analyses of Twelve New Whole Genome Sequences of Cassava Brown Streak Viruses and Ugandan Cassava Brown Streak Viruses from East Africa: Diversity, Supercomputing and Evidence for Further Speciation. PLoS One 2015; 10:e0139321. [PMID: 26439260 PMCID: PMC4595453 DOI: 10.1371/journal.pone.0139321] [Citation(s) in RCA: 50] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2015] [Accepted: 09/11/2015] [Indexed: 11/19/2022] Open
Abstract
Cassava brown streak disease is caused by two devastating viruses, Cassava brown streak virus (CBSV) and Ugandan cassava brown streak virus (UCBSV) which are frequently found infecting cassava, one of sub-Saharan Africa's most important staple food crops. Each year these viruses cause losses of up to $100 million USD and can leave entire families without their primary food source, for an entire year. Twelve new whole genomes, including seven of CBSV and five of UCBSV were uncovered in this research, doubling the genomic sequences available in the public domain for these viruses. These new sequences disprove the assumption that the viruses are limited by agro-ecological zones, show that current diagnostic primers are insufficient to provide confident diagnosis of these viruses and give rise to the possibility that there may be as many as four distinct species of virus. Utilizing NGS sequencing technologies and proper phylogenetic practices will rapidly increase the solution to sustainable cassava production.
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Affiliation(s)
- Joseph Ndunguru
- Mikocheni Agricultural Research Institute, Sam Nujoma Road, Box 6226, Dar es Salaam, Tanzania
| | - Peter Sseruwagi
- Mikocheni Agricultural Research Institute, Sam Nujoma Road, Box 6226, Dar es Salaam, Tanzania
| | - Fred Tairo
- Mikocheni Agricultural Research Institute, Sam Nujoma Road, Box 6226, Dar es Salaam, Tanzania
| | - Francesca Stomeo
- Biosciences eastern and central Africa, The International Livestock Research Institute in Nairobi, Kenya (the BecA-ILRI Hub), P.O. Box 30709, Nairobi 00100, Kenya
| | - Solomon Maina
- Biosciences eastern and central Africa, The International Livestock Research Institute in Nairobi, Kenya (the BecA-ILRI Hub), P.O. Box 30709, Nairobi 00100, Kenya
| | - Appolinaire Djinkeng
- Biosciences eastern and central Africa, The International Livestock Research Institute in Nairobi, Kenya (the BecA-ILRI Hub), P.O. Box 30709, Nairobi 00100, Kenya
| | - Monica Kehoe
- Crop Protection Branch, Department of Agriculture and Food Western Australia, Bentley Delivery Centre, Perth 6983, Western Australia, Australia
| | - Laura M. Boykin
- The University of Western Australia, ARC Centre of Excellence in Plant Energy Biology and School of Chemistry and Biochemistry, Crawley, Perth 6009, Western Australia, Australia
- * E-mail:
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76
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Patil BL, Legg JP, Kanju E, Fauquet CM. Cassava brown streak disease: a threat to food security in Africa. J Gen Virol 2015; 96:956-68. [PMID: 26015320 DOI: 10.1099/vir.0.000014] [Citation(s) in RCA: 61] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Cassava brown streak disease (CBSD) has emerged as the most important viral disease of cassava (Manihot esculenta) in Africa and is a major threat to food security. CBSD is caused by two distinct species of ipomoviruses, Cassava brown streak virus and Ugandan cassava brown streak virus, belonging to the family Potyviridae. Previously, CBSD was reported only from the coastal lowlands of East Africa, but recently it has begun to spread as an epidemic throughout the Great Lakes region of East and Central Africa. This new spread represents a major threat to the cassava-growing regions of West Africa. CBSD-resistant cassava cultivars are being developed through breeding, and transgenic RNA interference-derived field resistance to CBSD has also been demonstrated. This review aims to provide a summary of the most important studies on the aetiology, epidemiology and control of CBSD and to highlight key research areas that need prioritization.
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Affiliation(s)
- Basavaprabhu L Patil
- National Research Centre on Plant Biotechnology, IARI, Pusa Campus, New Delhi 110012, India
| | - James P Legg
- International Institute of Tropical Agriculture, PO Box 34441, Dar-Es-Salaam, Tanzania
| | - Edward Kanju
- International Institute of Tropical Agriculture, PO Box 34441, Dar-Es-Salaam, Tanzania
| | - Claude M Fauquet
- Centro Internacional de Agricultura Tropical, Apartado Aéreo 6713, Cali, Colombia
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Ghosh S, Bouvaine S, Maruthi MN. Prevalence and genetic diversity of endosymbiotic bacteria infecting cassava whiteflies in Africa. BMC Microbiol 2015; 15:93. [PMID: 25933928 PMCID: PMC4434523 DOI: 10.1186/s12866-015-0425-5] [Citation(s) in RCA: 48] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2014] [Accepted: 04/15/2015] [Indexed: 01/08/2023] Open
Abstract
BACKGROUND Cassava provides over half of the dietary requirement for more than 200 million poor in Africa. In recent years, cassava has been affected by an epidemic of a virus disease called cassava brown streak disease (CBSD) that is spreading in much of eastern and central Africa, affecting food security and the economic development of the poor. The viruses that cause CBSD are transmitted by the insect vector whitefly (Bemisia tabaci), which have increased to very high numbers in some African countries. Strains of endosymbiotic bacteria infecting whiteflies have been reported to interact specifically with different whitefly populations with varied effects on its host biology and efficiency of virus transmission. The main aim of this study was therefore to investigate the prevalence and diversity of the secondary endosymbiotic bacteria infecting cassava whiteflies with a view to better understand their role on insect population dynamics and virus disease epidemics. RESULTS The genetic diversity of field-collected whitefly from Tanzania, Malawi, Uganda and Nigeria was determined by mitochondrial DNA based phylogeny and restriction fragment length polymorphism. Cassava in these countries was infected with five whitefly populations, and each one was infected with different endosymbiotic bacteria. Incidences of Arsenophonus, Rickettsia, Wolbachia and Cardinium varied amongst the populations. Wolbachia was the most predominant symbiont with infection levels varying from 21 to 97%. Infection levels of Arsenophonus varied from 17 to 64% and that of Rickettsia was 0 to 53%. Hamiltonella and Fritschea were absent in all the samples. Multiple locus sequence typing identified four different strains of Wolbachia infecting cassava whiteflies. A common strain of Wolbachia infected the whitefly population Sub-Saharan Africa 1-subgroup 1 (SSA1-SG1) and SSA1-SG2, while others were infected with different strains. Phylogeny based on 16S rDNA of Rickettsia and 23S rDNA of Arsenophonus also identified distinct strains. CONCLUSIONS Genetically diverse bacteria infect cassava whiteflies in Africa with varied prevalence across different host populations, which may affect their whitefly biology. Further studies are required to investigate the role of endosymbionts to better understand the whitefly population dynamics.
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Affiliation(s)
- Saptarshi Ghosh
- Natural Resources Institute, University of Greenwich, Chatham, ME4 4 TB, Kent, UK.
| | - Sophie Bouvaine
- Natural Resources Institute, University of Greenwich, Chatham, ME4 4 TB, Kent, UK.
| | - M N Maruthi
- Natural Resources Institute, University of Greenwich, Chatham, ME4 4 TB, Kent, UK.
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78
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Patil BL, Legg JP, Kanju E, Fauquet CM. Cassava brown streak disease: a threat to food security in Africa. J Gen Virol 2015. [DOI: 10.1099/jgv.0.000014] [Citation(s) in RCA: 48] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023] Open
Affiliation(s)
- Basavaprabhu L. Patil
- National Research Centre on Plant Biotechnology, IARI, Pusa Campus, New Delhi 110012, India
| | - James P. Legg
- International Institute of Tropical Agriculture, PO Box 34441, Dar-Es-Salaam, Tanzania
| | - Edward Kanju
- International Institute of Tropical Agriculture, PO Box 34441, Dar-Es-Salaam, Tanzania
| | - Claude M. Fauquet
- Centro Internacional de Agricultura Tropical, Apartado Aéreo 6713, Cali, Colombia
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Jeremiah SC, Ndyetabula IL, Mkamilo GS, Haji S, Muhanna MM, Chuwa C, Kasele S, Bouwmeester H, Ijumba JN, Legg JP. The Dynamics and Environmental Influence on Interactions Between Cassava Brown Streak Disease and the Whitefly, Bemisia tabaci. PHYTOPATHOLOGY 2015; 105:646-55. [PMID: 25585059 DOI: 10.1094/phyto-05-14-0146-r] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/05/2023]
Abstract
Cassava brown streak disease (CBSD) is currently the most significant virus disease phenomenon affecting African agriculture. In this study, we report results from the most extensive set of field data so far presented for CBSD in Africa. From assessments of 515 farmers' plantings of cassava, incidence in the Coastal Zone of Tanzania (46.5% of plants; 87% of fields affected) was higher than in the Lake Zone (22%; 34%), but incidences for both zones were greater than previous published records. The whitefly vector, Bemisia tabaci, was more abundant in the Lake Zone than the Coastal Zone, the reverse of the situation reported previously, and increased B. tabaci abundance is driving CBSD spread in the Lake Zone. The altitudinal "ceiling" previously thought to restrict the occurrence of CBSD to regions <1,000 masl has been broken as a consequence of the greatly increased abundance of B. tabaci in mid-altitude areas. Among environmental variables analyzed, minimum temperature was the strongest determinant of CBSD incidence. B. tabaci in the Coastal and Lake Zones responded differently to environmental variables examined, highlighting the biological differences between B. tabaci genotypes occurring in these regions and the superior adaptation of B. tabaci in the Great Lakes region both to cassava and low temperature conditions. Regression analyses using multi-country data sets could be used to determine the potential environmental limits of CBSD. Approaches such as this offer potential for use in the development of predictive models for CBSD, which could strengthen country- and continent-level CBSD pandemic mitigation strategies.
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Affiliation(s)
- S C Jeremiah
- First, sixth, and seventh authors: Ministry of Agriculture, Food Security and Cooperatives-Ukiriguru Research, P.O. Box 1433, Mwanza, Tanzania; second author: Ministry of Agriculture, Food Security and Cooperatives-Maruku Research, P.O. Box 127, Bukoba, Tanzania; third author: Ministry of Agriculture, Food Security and Cooperatives-Naliendele Research, P.O. Box 509, Mtwara, Tanzania; fourth author: Ministry of Agriculture, Food Security and Cooperatives-Kizimbani Research, P.O. Box 159, Zanzibar, Tanzania; fifth author: Ministry of Agriculture, Food Security and Cooperatives-Kibaha Research, P.O. Box 30031, Kibaha, Tanzania; eighth author: Geospace, Roseboomlaan 38, 6717 ZB Ede, Netherlands; ninth author: Nelson Mandela African Institute of Science and Technology, P.O. Box 447, Arusha, Tanzania; and tenth author: International Institute of Tropical Agriculture, P.O. Box 34441, Dar es Salaam, Tanzania
| | - I L Ndyetabula
- First, sixth, and seventh authors: Ministry of Agriculture, Food Security and Cooperatives-Ukiriguru Research, P.O. Box 1433, Mwanza, Tanzania; second author: Ministry of Agriculture, Food Security and Cooperatives-Maruku Research, P.O. Box 127, Bukoba, Tanzania; third author: Ministry of Agriculture, Food Security and Cooperatives-Naliendele Research, P.O. Box 509, Mtwara, Tanzania; fourth author: Ministry of Agriculture, Food Security and Cooperatives-Kizimbani Research, P.O. Box 159, Zanzibar, Tanzania; fifth author: Ministry of Agriculture, Food Security and Cooperatives-Kibaha Research, P.O. Box 30031, Kibaha, Tanzania; eighth author: Geospace, Roseboomlaan 38, 6717 ZB Ede, Netherlands; ninth author: Nelson Mandela African Institute of Science and Technology, P.O. Box 447, Arusha, Tanzania; and tenth author: International Institute of Tropical Agriculture, P.O. Box 34441, Dar es Salaam, Tanzania
| | - G S Mkamilo
- First, sixth, and seventh authors: Ministry of Agriculture, Food Security and Cooperatives-Ukiriguru Research, P.O. Box 1433, Mwanza, Tanzania; second author: Ministry of Agriculture, Food Security and Cooperatives-Maruku Research, P.O. Box 127, Bukoba, Tanzania; third author: Ministry of Agriculture, Food Security and Cooperatives-Naliendele Research, P.O. Box 509, Mtwara, Tanzania; fourth author: Ministry of Agriculture, Food Security and Cooperatives-Kizimbani Research, P.O. Box 159, Zanzibar, Tanzania; fifth author: Ministry of Agriculture, Food Security and Cooperatives-Kibaha Research, P.O. Box 30031, Kibaha, Tanzania; eighth author: Geospace, Roseboomlaan 38, 6717 ZB Ede, Netherlands; ninth author: Nelson Mandela African Institute of Science and Technology, P.O. Box 447, Arusha, Tanzania; and tenth author: International Institute of Tropical Agriculture, P.O. Box 34441, Dar es Salaam, Tanzania
| | - S Haji
- First, sixth, and seventh authors: Ministry of Agriculture, Food Security and Cooperatives-Ukiriguru Research, P.O. Box 1433, Mwanza, Tanzania; second author: Ministry of Agriculture, Food Security and Cooperatives-Maruku Research, P.O. Box 127, Bukoba, Tanzania; third author: Ministry of Agriculture, Food Security and Cooperatives-Naliendele Research, P.O. Box 509, Mtwara, Tanzania; fourth author: Ministry of Agriculture, Food Security and Cooperatives-Kizimbani Research, P.O. Box 159, Zanzibar, Tanzania; fifth author: Ministry of Agriculture, Food Security and Cooperatives-Kibaha Research, P.O. Box 30031, Kibaha, Tanzania; eighth author: Geospace, Roseboomlaan 38, 6717 ZB Ede, Netherlands; ninth author: Nelson Mandela African Institute of Science and Technology, P.O. Box 447, Arusha, Tanzania; and tenth author: International Institute of Tropical Agriculture, P.O. Box 34441, Dar es Salaam, Tanzania
| | - M M Muhanna
- First, sixth, and seventh authors: Ministry of Agriculture, Food Security and Cooperatives-Ukiriguru Research, P.O. Box 1433, Mwanza, Tanzania; second author: Ministry of Agriculture, Food Security and Cooperatives-Maruku Research, P.O. Box 127, Bukoba, Tanzania; third author: Ministry of Agriculture, Food Security and Cooperatives-Naliendele Research, P.O. Box 509, Mtwara, Tanzania; fourth author: Ministry of Agriculture, Food Security and Cooperatives-Kizimbani Research, P.O. Box 159, Zanzibar, Tanzania; fifth author: Ministry of Agriculture, Food Security and Cooperatives-Kibaha Research, P.O. Box 30031, Kibaha, Tanzania; eighth author: Geospace, Roseboomlaan 38, 6717 ZB Ede, Netherlands; ninth author: Nelson Mandela African Institute of Science and Technology, P.O. Box 447, Arusha, Tanzania; and tenth author: International Institute of Tropical Agriculture, P.O. Box 34441, Dar es Salaam, Tanzania
| | - C Chuwa
- First, sixth, and seventh authors: Ministry of Agriculture, Food Security and Cooperatives-Ukiriguru Research, P.O. Box 1433, Mwanza, Tanzania; second author: Ministry of Agriculture, Food Security and Cooperatives-Maruku Research, P.O. Box 127, Bukoba, Tanzania; third author: Ministry of Agriculture, Food Security and Cooperatives-Naliendele Research, P.O. Box 509, Mtwara, Tanzania; fourth author: Ministry of Agriculture, Food Security and Cooperatives-Kizimbani Research, P.O. Box 159, Zanzibar, Tanzania; fifth author: Ministry of Agriculture, Food Security and Cooperatives-Kibaha Research, P.O. Box 30031, Kibaha, Tanzania; eighth author: Geospace, Roseboomlaan 38, 6717 ZB Ede, Netherlands; ninth author: Nelson Mandela African Institute of Science and Technology, P.O. Box 447, Arusha, Tanzania; and tenth author: International Institute of Tropical Agriculture, P.O. Box 34441, Dar es Salaam, Tanzania
| | - S Kasele
- First, sixth, and seventh authors: Ministry of Agriculture, Food Security and Cooperatives-Ukiriguru Research, P.O. Box 1433, Mwanza, Tanzania; second author: Ministry of Agriculture, Food Security and Cooperatives-Maruku Research, P.O. Box 127, Bukoba, Tanzania; third author: Ministry of Agriculture, Food Security and Cooperatives-Naliendele Research, P.O. Box 509, Mtwara, Tanzania; fourth author: Ministry of Agriculture, Food Security and Cooperatives-Kizimbani Research, P.O. Box 159, Zanzibar, Tanzania; fifth author: Ministry of Agriculture, Food Security and Cooperatives-Kibaha Research, P.O. Box 30031, Kibaha, Tanzania; eighth author: Geospace, Roseboomlaan 38, 6717 ZB Ede, Netherlands; ninth author: Nelson Mandela African Institute of Science and Technology, P.O. Box 447, Arusha, Tanzania; and tenth author: International Institute of Tropical Agriculture, P.O. Box 34441, Dar es Salaam, Tanzania
| | - H Bouwmeester
- First, sixth, and seventh authors: Ministry of Agriculture, Food Security and Cooperatives-Ukiriguru Research, P.O. Box 1433, Mwanza, Tanzania; second author: Ministry of Agriculture, Food Security and Cooperatives-Maruku Research, P.O. Box 127, Bukoba, Tanzania; third author: Ministry of Agriculture, Food Security and Cooperatives-Naliendele Research, P.O. Box 509, Mtwara, Tanzania; fourth author: Ministry of Agriculture, Food Security and Cooperatives-Kizimbani Research, P.O. Box 159, Zanzibar, Tanzania; fifth author: Ministry of Agriculture, Food Security and Cooperatives-Kibaha Research, P.O. Box 30031, Kibaha, Tanzania; eighth author: Geospace, Roseboomlaan 38, 6717 ZB Ede, Netherlands; ninth author: Nelson Mandela African Institute of Science and Technology, P.O. Box 447, Arusha, Tanzania; and tenth author: International Institute of Tropical Agriculture, P.O. Box 34441, Dar es Salaam, Tanzania
| | - J N Ijumba
- First, sixth, and seventh authors: Ministry of Agriculture, Food Security and Cooperatives-Ukiriguru Research, P.O. Box 1433, Mwanza, Tanzania; second author: Ministry of Agriculture, Food Security and Cooperatives-Maruku Research, P.O. Box 127, Bukoba, Tanzania; third author: Ministry of Agriculture, Food Security and Cooperatives-Naliendele Research, P.O. Box 509, Mtwara, Tanzania; fourth author: Ministry of Agriculture, Food Security and Cooperatives-Kizimbani Research, P.O. Box 159, Zanzibar, Tanzania; fifth author: Ministry of Agriculture, Food Security and Cooperatives-Kibaha Research, P.O. Box 30031, Kibaha, Tanzania; eighth author: Geospace, Roseboomlaan 38, 6717 ZB Ede, Netherlands; ninth author: Nelson Mandela African Institute of Science and Technology, P.O. Box 447, Arusha, Tanzania; and tenth author: International Institute of Tropical Agriculture, P.O. Box 34441, Dar es Salaam, Tanzania
| | - J P Legg
- First, sixth, and seventh authors: Ministry of Agriculture, Food Security and Cooperatives-Ukiriguru Research, P.O. Box 1433, Mwanza, Tanzania; second author: Ministry of Agriculture, Food Security and Cooperatives-Maruku Research, P.O. Box 127, Bukoba, Tanzania; third author: Ministry of Agriculture, Food Security and Cooperatives-Naliendele Research, P.O. Box 509, Mtwara, Tanzania; fourth author: Ministry of Agriculture, Food Security and Cooperatives-Kizimbani Research, P.O. Box 159, Zanzibar, Tanzania; fifth author: Ministry of Agriculture, Food Security and Cooperatives-Kibaha Research, P.O. Box 30031, Kibaha, Tanzania; eighth author: Geospace, Roseboomlaan 38, 6717 ZB Ede, Netherlands; ninth author: Nelson Mandela African Institute of Science and Technology, P.O. Box 447, Arusha, Tanzania; and tenth author: International Institute of Tropical Agriculture, P.O. Box 34441, Dar es Salaam, Tanzania
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Leke WN, Mignouna DB, Brown JK, Kvarnheden A. Begomovirus disease complex: emerging threat to vegetable production systems of West and Central Africa. ACTA ACUST UNITED AC 2015. [DOI: 10.1186/s40066-014-0020-2] [Citation(s) in RCA: 51] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
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Legg JP, Lava Kumar P, Makeshkumar T, Tripathi L, Ferguson M, Kanju E, Ntawuruhunga P, Cuellar W. Cassava virus diseases: biology, epidemiology, and management. Adv Virus Res 2015; 91:85-142. [PMID: 25591878 DOI: 10.1016/bs.aivir.2014.10.001] [Citation(s) in RCA: 103] [Impact Index Per Article: 11.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Cassava (Manihot esculenta Crantz.) is the most important vegetatively propagated food staple in Africa and a prominent industrial crop in Latin America and Asia. Its vegetative propagation through stem cuttings has many advantages, but deleteriously it means that pathogens are passed from one generation to the next and can easily accumulate, threatening cassava production. Cassava-growing continents are characterized by specific suites of viruses that affect cassava and pose particular threats. Of major concern, causing large and increasing economic impact in Africa and Asia are the cassava mosaic geminiviruses that cause cassava mosaic disease in Africa and Asia and cassava brown streak viruses causing cassava brown streak disease in Africa. Latin America, the center of origin and domestication of the crop, hosts a diverse set of virus species, of which the most economically important give rise to cassava frog skin disease syndrome. Here, we review current knowledge on the biology, epidemiology, and control of the most economically important groups of viruses in relation to both farming and cultural practices. Components of virus control strategies examined include: diagnostics and surveillance, prevention and control of infection using phytosanitation, and control of disease through the breeding and promotion of varieties that inhibit virus replication and/or movement. We highlight areas that need further research attention and conclude by examining the likely future global outlook for virus disease management in cassava.
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Affiliation(s)
- James P Legg
- International Institute of Tropical Agriculture (IITA), Dar es Salaam, Tanzania.
| | - P Lava Kumar
- International Institute of Tropical Agriculture (IITA), Ibadan, Nigeria
| | - T Makeshkumar
- Central Tuber Crops Research Institute (CTCRI), Thiruvananthapuram, India
| | - Leena Tripathi
- International Institute of Tropical Agriculture (IITA), Nairobi, Kenya
| | - Morag Ferguson
- International Institute of Tropical Agriculture (IITA), Nairobi, Kenya
| | - Edward Kanju
- International Institute of Tropical Agriculture (IITA), Dar es Salaam, Tanzania
| | | | - Wilmer Cuellar
- Centro Internacional de Agricultura Tropical (CIAT), Cali, Colombia
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Legg JP, Shirima R, Tajebe LS, Guastella D, Boniface S, Jeremiah S, Nsami E, Chikoti P, Rapisarda C. Biology and management of Bemisia whitefly vectors of cassava virus pandemics in Africa. PEST MANAGEMENT SCIENCE 2014; 70:1446-53. [PMID: 24706604 DOI: 10.1002/ps.3793] [Citation(s) in RCA: 54] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/29/2013] [Revised: 03/12/2014] [Accepted: 03/31/2014] [Indexed: 05/26/2023]
Abstract
Cassava mosaic disease and cassava brown streak disease are caused by viruses transmitted by Bemisia tabaci and affect approximately half of all cassava plants in Africa, resulting in annual production losses of more than $US 1 billion. A historical and current bias towards virus rather than vector control means that these diseases continue to spread, and high Bemisia populations threaten future virus spread even if the extant strains and species are controlled. Progress has been made in parts of Africa in replicating some of the successes of integrated Bemisia control programmes in the south-western United States. However, these management efforts, which utilise chemical insecticides that conserve the Bemisia natural enemy fauna, are only suitable for commercial agriculture, which presently excludes most cassava cultivation in Africa. Initiatives to strengthen the control of B. tabaci on cassava in Africa need to be aware of this limitation, and to focus primarily on control methods that are cheap, effective, sustainable and readily disseminated, such as host-plant resistance and biological control. A framework based on the application of force multipliers is proposed as a means of prioritising elements of future Bemisia control strategies for cassava in Africa.
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Affiliation(s)
- James P Legg
- International Institute of Tropical Agriculture, Dar es Salaam, Tanzania
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Abstract
Whiteflies are a key pest of crops in open-field production throughout the tropics and subtropics. This is due in large part to the long and diverse list of devastating plant viruses transmitted by these vectors. Open-field production provides many challenges to manage these viruses and in many cases adequate management has not been possible. Diseases caused by whitefly-transmitted viruses have become limiting factors in open-field production of a wide range of crops, i.e., bean golden mosaic disease in beans, tomato yellow leaf curl disease in tomato, cassava mosaic disease and cassava brown streak disease in cassava, and cotton leaf crumple disease in cotton. While host resistance has proven to be the most cost-effective management solution, few examples of host resistance have been developed to date. The main strategy to limit the incidence of virus-infected plants has been the application of insecticides to reduce vector populations aided to some extent by the use of selected cultural practices. However, due to concerns about the effect of insecticides on pollinators, consumer demand for reduced pesticide use, and the ability of the whitefly vectors to develop insecticide-resistance, there is a growing need to develop and deploy strategies that do not rely on insecticides. The reduction in pesticide use will greatly increase the need for genetic resistance to more viruses in more crop plants. Resistance combined with selected IPM strategies could become a viable means to increase yields in crops produced in open fields despite the presence of whitefly-transmitted viruses.
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