First report of banana bunchy top virus in banana and plantain (Musa spp.) in Tanzania

Banana (including plantain; Musa spp.) is an important vegetatively propagated food staple grown as a semi-perennial crop in fields and backyard gardens in Tanzania. Banana bunchy top disease (BBTD), caused by the banana bunchy top virus (BBTV, genus Babuvirus), is the most economically important viral disease of banana, infection of which results in severe stunting and reduction in fruit production by 90-100% within two seasons. The virus is spread by the banana aphid, Pentalonia nigronervosa, and through vegetative propagation of infected sources. BBTV is an introduced virus first reported in sub-Saharan Africa (SSA) in the 1960s in the Democratic Republic of Congo. Since then, BBTV spread was confirmed in 15 countries in Central, Southern, and Western African regions but was not detected in any previous surveys in the East African sub-region. During banana pests and disease surveys conducted in December 2020 – January 2021 in Buhigwe District in the Kigoma Region of Tanzania revealed banana plants with typical BBTV symptoms (severe stunting, leaves with shortened petioles, chlorotic streaks, and yellow leaf margins) in several banana fields in Muhinda (lon. 29.78662, lat. -4.53672) and Mwayaya (lon. 29.8218, lat. -4.49203) villages. Most of the affected plantations were 5 to 15 years old. Leaf samples (N=21) from symptomatic (N=6) and asymptomatic (N=15) banana plants were collected and used for total DNA extraction and BBTV detection by polymerase chain reaction (PCR) using the primer pair BBTV-1 and BBTV-2 to amplify ~240 bp sequence of DNA-R encoding for core master replication initiator protein gene. All samples from symptomatic plants tested positive and asymptomatic plants were negative. To further confirm the virus identity, four samples, each from symptomatic (PCR positive) and asymptomatic (PCR negative) plants from Muhinda and Mwayaya villages, were tested by Triple Antibody Sandwich-Enzyme-linked Immunosorbent Assay (TAS-ELISA) using BBTV ELISA reagent set (Cat. # SRA24700-1000, Agdia, France) following the manufacturer's protocol. Samples from symptomatic plants reacted positively in TAS-ELISA, and asymptomatic plants were negative. The 240-bp PCR product of two isolates was purified, and both strands were sequenced. A BLAST search of the nucleotide sequences (NCBI GenBank Acc.# MW711671 and MW711672) revealed 99% identity with DNA-R sequences of several other BBTV isolates from Africa (Acc. No# JF755994). Further analysis of the 240-bp nucleotide sequences with Maximum-likelihood phylogenetic analysis using MEGA-X software has grouped the two BBTV sequence isolates with the SSA sub-clade of the South-Pacific group. To our knowledge, this is the first report of BBTV infecting bananas in Tanzania, and East Africa endowed with rich banana diversity and popular East African Highland banana clone. BBTV presents a new threat to banana production in this sub-region due to the high risk of further spread through vegetative propagation, traditional planting material exchange practices, and the ubiquitous banana aphid vector. This study warrants delimitation surveys to assess the extent of spread, with simultaneous efforts to raise awareness about BBTD recognition and control measures among banana growers, including eradicating infected mats and replanting with healthy planting material to recover banana production.

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First report of banana bunchy top virus in banana (Musa spp.) and its eradication in Togo

Plant Disease ◽

10.1094/pdis-03-21-0473-pdn ◽

2021 ◽

Author(s):

Yao Kolombia ◽

Taiwo Oviasuyi ◽

Kwasi Dzola AYISAH ◽

Ayefouni Ale Gonh-Goh ◽

Tagba Atsu ◽

...

Keyword(s):

Sub Saharan Africa ◽

Replicase Gene ◽

Banana Bunchy Top Virus ◽

First Report ◽

Severe Stunting ◽

Musa Spp ◽

First Case ◽

Two Samples ◽

Sub Saharan

Banana (including plantain; Musa spp.) is a vegetatively propagated semi-perennial crop in fields and backyard gardens in Togo. Banana bunchy top disease (BBTD), caused by banana bunchy top virus (BBTV, genus Babuvirus) is the most economically important viral disease, infection of which causes severe stunting and production losses of 90-100% within two seasons. The virus is spread by banana aphid, Pentalonia nigronervosa, and through vegetative propagation from infected sources. BBTV occurrence was first reported in West Africa in 2011 with confirmation in Republic of Benin and in Nigeria in 2012 . A regional alliance (www.bbtvalliance.org) has been established for BBTV surveillance through frequent surveys in countries neighboring those affected, such as Togo. The surveys conducted in September 2018 in banana growing areas in Togo revealed plants with typical symptoms (severe stunting, bunchy growth with shortened petioles with chlorotic streaks and yellow leaf margins) in three banana fields. Locations were Tsévié, Préfecture de Zio, (6.44°N, 1.21028°E), Lilicope, Préfecture de Zio in Maritime region (6.56583°N, 1.18639°E), and Amoutchou, Préfecture de l’Ogou in Plateaux region (7.3775°N, 1.17472°E). Leaf samples were collected from symptomatic (N=8) and asymptomatic plants (N=30) and used for DNA extraction followed by a polymerase chain reaction (PCR) for BBTV detection to amplify ~240 bp sequence of DNA-R encoding for core replicase gene. All samples from symptomatic plants (N=8) tested positive and asymptomatic plants were negative. To ascertain virus identity the 240-bp PCR product was purified and sequenced in both directions. A BLAST search of the sequence (NCBI GenBank Acc.# MK073116) revealed 99% identity with DNA-R sequences of BBTV isolates from Africa (e.g., JQ437549-Benin, JN290301-Nigeria). Further analysis of the 240-bp nucleotide sequence with Maximum-likelihood phylogenetic analysis using MEGA-X software has grouped the BBTV isolate with sub-Saharan African sub-clade of the South Pacific group. To further confirm the virus identity, two samples from symptomatic (PCR positive) and asymptomatic (PCR negative) plants from Tsévié were tested by TAS-ELISA using BBTV ELISA reagent set (Cat. No. SRA24700-1000, Agdia, France) following the manufacturers’ protocol. Only samples from two symptomatic plants that were positive in PCR reacted positively in TAS-ELISA; asymptomatic plants were negative. BBTV was not observed in any of the 22 locations surveyed as a follow-up in banana producing areas. To our knowledge, this is the first report of BBTV infecting banana in Togo. The plants detected in the three sites were eradicated in the follow-up action implemented by the alliance team together with the Direction de la Protection des Végétaux of Togo. Follow-up surveys were conducted in the same regions in 2019 and 2020 to ensure disease-free status in these sites and other banana producing regions in Togo. Efforts have been made to raise awareness about BBTD recognition, diagnosis, and eradication. To the best of our knowledge this is the first case of rapid detection and eradication of BBTD in sub-Saharan Africa. This study illustrates the importance of regular surveillance for early detection of invasive virus threats and the value of rapid eradication to contain viruses before spread and establishment in a new territory.

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First Report of Banana bunchy top virus in Banana (Musa spp.) from South Africa

Plant Disease ◽

10.1094/pdis-12-15-1422-pdn ◽

2016 ◽

Vol 100 (6) ◽

pp. 1251 ◽

Cited By ~ 12

Author(s):

A. E. C. Jooste ◽

N. Wessels ◽

M. van der Merwe

Keyword(s):

South Africa ◽

Banana Bunchy Top Virus ◽

First Report ◽

Musa Spp

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First Report of Banana Streak Virus Infecting Banana Cultivars (Musa spp.) in Taiwan

Plant Disease ◽

10.1094/pdis.1997.81.5.550a ◽

1997 ◽

Vol 81 (5) ◽

pp. 550-550 ◽

Cited By ~ 1

Author(s):

Hong-Ji Su ◽

Ting-Hsuan Hung ◽

Meng-Ling Wu

Keyword(s):

Enzyme Linked Immunosorbent Assay ◽

Streak Virus ◽

Banana Streak Virus ◽

Banana Bunchy Top Virus ◽

Citrus Mealybug ◽

First Report ◽

Musa Spp ◽

Cavendish Banana ◽

Southern Taiwan ◽

Leaf Symptoms

Banana (Musa sapientam L.) is an economically important crop for both export and local consumption in Taiwan. Recently, leaf symptoms characteristic of banana streak disease (1) were found on banana cv. Mysore (AAB group) introduced from Australia in the germ plasm collection of the Taiwan Banana Research Institute. The citrus mealybug (Planococus citri) has been shown to transmit banana streak virus (BSV) but not banana bunchy top virus or cucumber mosaic virus (CMV) (2). When mealybugs were fed on leaves of diseased Mysore banana and transferred to healthy banana cv. Cavendish seedlings in a growth chamber, the latter developed fine chlorotic streaks characteristic of symptoms caused by BSV within 1 to 3 months. Some chlorotic streaks became necrotic. BSV was detected in diseased but not healthy leaves of Mysore and Cavendish bananas by polymerase chain reaction (PCR) with primer pairs of BSV provided by J. E. Thomas of Queensland Department of Primary Industries. Subsequently, fine chlorotic streaks were observed in leaves of Cavendish banana in several fields in southern Taiwan. Some of these diseased plants developed severe leaf necrosis, causing heart rot of spindle leaves characteristic of symptoms caused by CMV. Presence of BSV in these plants was verified by PCR assay. However, CMV was also detected by double antibody sandwich-enzyme-linked immunosorbent assay with a monoclonal antibody to CMV, indicating that these plants were simultaneously infected by both viruses. This is the first report of BSV infecting Musa spp. in Taiwan. References: (1) B. E. L. Lockhart. Phytopathology 76:995, 1986. (2) B. E. L. Lockhart. 1995 Food & Fertilizer Technol. Center (ASPAC) Tech. Bull. 143. 11 pp.

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Effect of Seasonal Drought on the Agronomic Performance of Four Banana Genotypes (Musa spp.) in the East African Highlands

Agronomy ◽

10.3390/agronomy11010004 ◽

2020 ◽

Vol 11 (1) ◽

pp. 4

Author(s):

Brigitte Uwimana ◽

Yasmín Zorrilla-Fontanesi ◽

Jelle van Wesemael ◽

Hassan Mduma ◽

Allan Brown ◽

...

Keyword(s):

Yield Traits ◽

East African ◽

Ploidy Levels ◽

Early Effect ◽

Seasonal Drought ◽

Musa Spp ◽

Drought Tolerant ◽

Genome Group ◽

African Highlands ◽

East African Highlands

Banana (Musa spp.), a perennial (sub-)tropical crop, suffers from seasonal droughts, which are typical of rain-fed agriculture. This study aimed at understanding the effect of seasonal drought on early growth, flowering and yield traits in bananas grown in the East African highlands. A field experiment was set up in North Tanzania using four genotypes from different geographical origins and two different ploidy levels. The treatments considered were exclusively rain-fed versus rain supplemented with irrigation. Growth in plant girth and leaf area were promising traits to detect the early effect of water deficit. Seasonal drought slowed down vegetative growth, thus significantly decreasing plant girth, plant height and the number of suckers produced when compared to irrigated plants. It also delayed flowering time and bunch maturity and had a negative effect on yield traits. However, the results depended on the genotype and crop cycle and their interaction with the treatments. “Nakitengwa”, an East African highland banana (EAHB; AAA genome group), which is adapted to the region, showed sensitivity to drought in terms of reduced bunch weight and expected yield, while “Cachaco” (ABB genome group) showed less sensitivity to drought but had a poorer yield than “Nakitengwa”. Our study confirms that seasonal drought has a negative impact on banana production in East Africa, where EAHBs are the most predominant type of bananas grown in the region. We also show that a drought-tolerant cultivar not adapted to the East African highlands had a low performance in terms of yield. We recommend a large-scale screening of diploid bananas to identify drought-tolerant genotypes to be used in the improvement of locally adapted and accepted varieties.

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Serological survey and metagenomic discovery of potato viruses in Rwanda and Burundi reveals absence of PVY in Burundi and first report of TRV in potatoes in sub Saharan Africa

Virus Research ◽

10.1016/j.virusres.2021.198487 ◽

2021 ◽

pp. 198487

Author(s):

Joshua Sikhu Okonya ◽

Heidy Gamarra ◽

Anastase Nduwayezu ◽

Astere Bararyenya ◽

Jürgen Kroschel ◽

...

Keyword(s):

Sub Saharan Africa ◽

Serological Survey ◽

First Report ◽

Potato Viruses ◽

Sub Saharan

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Nutrient imbalance and yield limiting factors of low input East African highland banana (Musa spp. AAA-EA) cropping systems

Field Crops Research ◽

10.1016/j.fcr.2013.04.001 ◽

2013 ◽

Vol 147 ◽

pp. 68-78 ◽

Cited By ~ 10

Author(s):

T. Ndabamenye ◽

P.J.A. Van Asten ◽

G. Blomme ◽

B. Vanlauwe ◽

B. Uzayisenga ◽

...

Keyword(s):

Cropping Systems ◽

Limiting Factors ◽

East African ◽

Low Input ◽

Musa Spp ◽

Nutrient Imbalance

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RATE OF NEMATODE INFESTATION OF CLEAN BANANA PLANTING MATERIAL (MUSA SPP. AAA) IN UGANDA

Acta Horticulturae ◽

10.17660/actahortic.2000.540.52 ◽

2000 ◽

pp. 461-467 ◽

Cited By ~ 5

Author(s):

P.R. Speijer ◽

C.S. Gold ◽

B. Goossens ◽

E.B. Karamura ◽

A. Elsen ◽

...

Keyword(s):

Musa Spp ◽

Planting Material

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Characterizing the genomic variation and population dynamics of Plasmodium falciparum malaria parasites in and around Lake Victoria, Kenya

Scientific Reports ◽

10.1038/s41598-021-99192-1 ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

Ashley Osborne ◽

Emilia Manko ◽

Mika Takeda ◽

Akira Kaneko ◽

Wataru Kagaya ◽

...

Keyword(s):

Plasmodium Falciparum ◽

Population Dynamics ◽

Malaria Elimination ◽

Lake Victoria ◽

Genomic Variation ◽

Genomic Diversity ◽

Sub Saharan Africa ◽

Lake Victoria Basin ◽

East African ◽

Lake Region

AbstractCharacterising the genomic variation and population dynamics of Plasmodium falciparum parasites in high transmission regions of Sub-Saharan Africa is crucial to the long-term efficacy of regional malaria elimination campaigns and eradication. Whole-genome sequencing (WGS) technologies can contribute towards understanding the epidemiology and structural variation landscape of P. falciparum populations, including those within the Lake Victoria basin, a region of intense transmission. Here we provide a baseline assessment of the genomic diversity of P. falciparum isolates in the Lake region of Kenya, which has sparse genetic data. Lake region isolates are placed within the context of African-wide populations using Illumina WGS data and population genomic analyses. Our analysis revealed that P. falciparum isolates from Lake Victoria form a cluster within the East African parasite population. These isolates also appear to have distinct ancestral origins, containing genome-wide signatures from both Central and East African lineages. Known drug resistance biomarkers were observed at similar frequencies to those of East African parasite populations, including the S160N/T mutation in the pfap2mu gene, which has been associated with delayed clearance by artemisinin-based combination therapy. Overall, our work provides a first assessment of P. falciparum genetic diversity within the Lake Victoria basin, a region targeting malaria elimination.

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First Report of East African Cassava Mosaic Begomovirus in Nigeria

Plant Disease ◽

10.1094/pdis.1999.83.4.398a ◽

1999 ◽

Vol 83 (4) ◽

pp. 398-398 ◽

Cited By ~ 14

Author(s):

F. O. Ogbe ◽

G. I. Atiri ◽

D. Robinson ◽

S. Winter ◽

A. G. O. Dixon ◽

...

Keyword(s):

Central Africa ◽

Mosaic Disease ◽

Sub Saharan Africa ◽

Cassava Mosaic Disease ◽

Enzyme Linked Immunosorbent Assay ◽

East African ◽

African Countries ◽

Manihot Esculenta Crantz ◽

Cross River State ◽

Sub Saharan

Cassava (Manihot esculenta Crantz) is an important food crop in sub-Saharan Africa. One of the major production constraints is cassava mosaic disease caused by African cassava mosaic (ACMV) and East African cassava mosaic (EACMV) begomoviruses. ACMV is widespread in its distribution, occurring throughout West and Central Africa and in some eastern and southern African countries. In contrast, EACMV has been reported to occur mainly in more easterly areas, particularly in coastal Kenya and Tanzania, Malawi, and Madagascar. In 1997, a survey was conducted in Nigeria to determine the distribution of ACMV and its strains. Samples from 225 cassava plants showing mosaic symptoms were tested with ACMV monoclonal antibodies (MAbs) in triple antibody sandwich enzyme-linked immunosorbent assay (1). Three samples reacted strongly with MAbs that could detect both ACMV and EACMV. One of them did not react with ACMV-specific MAbs while the other two reacted weakly with such MAbs. With polymerase chain reaction (2), the presence of EACMV and a mixture of EACMV and ACMV in the respective samples was confirmed. These samples were collected from two villages: Ogbena in Kwara State and Akamkpa in Cross River State. Co-infection of some cassava varieties with ACMV and EACMV leads to severe symptoms. More importantly, a strain of mosaic geminivirus known as Uganda variant arose from recombination between the two viruses (2). This report provides evidence for the presence of EACMV in West Africa. References: (1) J. E. Thomas et al. J. Gen. Virol. 67:2739, 1986. (2) X. Zhou et al. J. Gen. Virol. 78:2101, 1997.

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Volcanic activity and hazard in the East African Rift Zone

Nature Communications ◽

10.1038/s41467-021-27166-y ◽

2021 ◽

Vol 12 (1) ◽

Author(s):

Juliet Biggs ◽

Atalay Ayele ◽

Tobias P. Fischer ◽

Karen Fontijn ◽

William Hutchison ◽

...

Keyword(s):

Volcanic Activity ◽

East African Rift ◽

Volcanic Hazards ◽

Crisis Response ◽

Sub Saharan Africa ◽

Rift System ◽

East African Rift System ◽

East African ◽

Sub Saharan ◽

African Rift

AbstractOver the past two decades, multidisciplinary studies have unearthed a rich history of volcanic activity and unrest in the densely-populated East African Rift System, providing new insights into the influence of rift dynamics on magmatism, the characteristics of the volcanic plumbing systems and the foundation for hazard assessments. The raised awareness of volcanic hazards is driving a shift from crisis response to reducing disaster risks, but a lack of institutional and human capacity in sub-Saharan Africa means baseline data are sparse and mitigating geohazards remains challenging.

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