scholarly journals Selecting for Coupling Phase Recombination between Potyvirus Resitance and White Endosperm Colour in Maize Preferred by Farmers in Sub-Saharan Africa (SSA)

Afrika Focus ◽  
2019 ◽  
Vol 32 (2) ◽  
Author(s):  
Victoria B. Bulegeya ◽  
Mark W. Jones ◽  
Tryphone G. Muhamba ◽  
Biswanath Das ◽  
Peter R. Thomison ◽  
...  
Keyword(s):  
Mosaic Virus ◽  
Genetic Recombination ◽  
Sub Saharan Africa ◽  
Maize Dwarf Mosaic Virus ◽  
Coupling Phase ◽  
Chlorotic Mottle Virus ◽  
Maize Chlorotic Mottle Virus ◽  
Chlorotic Mottle ◽  
Sub Saharan ◽  
Combined Infection

Maize lethal necrosis (MLN) disease caused by a combined infection of Maize chlorotic mottle virus (MCMV) and any cereal infecting potyvirus is a threat to food security in Sub-Saharan Africa (SSA). Resistance to potyvirus has been extensively studied and Mdm1 gene for potyvirus resistance on chromosome 6 of maize is linked to Y1 gene for maize endosperm colour. This study is aimed at se- lecting for coupling-phase recombination of potyvirus resistance and white endosperm colour. White susceptible maize lines CML333 and CML277 were crossed with a yellow resistant line, Pa405, to produce F1 and F2 progenies. Progenies were screened using molecular markers to recover 22 white endosperm recombinants. 22 selections were advanced to F3 recombinant families, and 10 were as- sayed for their responses to Maize dwarf mosaic virus (MDMV) and Sugarcane mosaic virus (SCMV). Four families segregated for SCMV resistance, selection of homozygous recombinants within these families will provide lines appropriate for improving lines with resistance to SCMV and MLN resistance in SSA. KEY WORDS: MAIZE LETHAL NECROSIS (MLN), WHITE MAIZE, POTYVIRUS RESISTANCE, GENETIC RECOMBINATION, SUB-SAHARAN AFRICA.

scholarly journals Selecting for Coupling-Phase Recombination Between Potyvirus Resistance and White Endosperm Colour in Maize Preferred by Farmers in Sub-Saharan Africa (SSA)

Afrika Focus ◽  
2019 ◽  
Vol 32 (2) ◽  
pp. 39-48
Author(s):  
Victoria B. Bulegeya ◽  
Mark W. Jones ◽  
Tryphone G. Muhamba ◽  
Biswanath Das ◽  
Peter R. Thomison ◽  
...  
Keyword(s):  
Mosaic Virus ◽  
Sub Saharan Africa ◽  
Maize Dwarf Mosaic Virus ◽  
Coupling Phase ◽  
Resistance Selection ◽  
Chlorotic Mottle Virus ◽  
Maize Chlorotic Mottle Virus ◽  
Chlorotic Mottle ◽  
Sub Saharan ◽  
Combined Infection

Maize lethal necrosis (MLN) disease caused by a combined infection of Maize chlorotic mottle virus (MCMV) and any cereal infecting potyvirus is a threat to food security in Sub-Saharan Africa (SSA). Resistance to potyvirus has been extensively studied and Mdm1 gene for potyvirus resistance on chromosome 6 of maize is linked to Y1 gene for maize endosperm colour. This study is aimed at selecting for coupling-phase recombination of potyvirus resistance and white endosperm colour. White susceptible maize lines CML333 and CML277 were crossed with a yellow resistant line, Pa405, to produce F1 and F2 progenies. Progenies were screened using molecular markers to recover 22 white endosperm recombinants. 22 selections were advanced to F3 recombinant families, and 10 were assayed for their responses to Maize dwarf mosaic virus (MDMV) and Sugarcane mosaic virus (SCMV). Four families segregated for SCMV resistance, selection of homozygous recombinants within these families will provide lines appropriate for improving lines with resistance to SCMV and MLN resistance in SSA.

Maize Lethal Necrosis: An Emerging, Synergistic Viral Disease

2018 ◽  
Vol 5 (1) ◽  
pp. 301-322 ◽  
Author(s):  
Margaret G. Redinbaugh ◽  
Lucy R. Stewart
Keyword(s):  
Mosaic Virus ◽  
Smallholder Farmers ◽  
Seed Transmission ◽  
Viral Disease ◽  
Maize Dwarf Mosaic Virus ◽  
Chlorotic Mottle Virus ◽  
Maize Chlorotic Mottle Virus ◽  
Chlorotic Mottle ◽  
Sub Saharan ◽  
And Control

Maize lethal necrosis (MLN) is a disease of maize caused by coinfection of maize with maize chlorotic mottle virus (MCMV) and one of several viruses from the Potyviridae, such as sugarcane mosaic virus, maize dwarf mosaic virus, Johnsongrass mosaic virus or wheat streak mosaic virus. The coinfecting viruses act synergistically to result in frequent plant death or severely reduce or negligible yield. Over the past eight years, MLN has emerged in sub-Saharan East Africa, Southeast Asia, and South America, with large impacts on smallholder farmers. Factors associated with MLN emergence include multiple maize crops per year, the presence of maize thrips ( Frankliniella williamsi), and highly susceptible maize crops. Soil and seed transmission of MCMV may also play significant roles in development and perpetuation of MLN epidemics. Containment and control of MLN will likely require a multipronged approach, and more research is needed to identify and develop the best measures.

scholarly journals Characterising maize viruses associated with maize lethal necrosis symptoms in sub Saharan Africa

2017 ◽  
Author(s):  
I.P. Adams ◽  
L.A. Braidwood ◽  
F. Stomeo ◽  
N. Phiri ◽  
B. Uwumukiza ◽  
...  
Keyword(s):  
Mosaic Virus ◽  
Sub Saharan Africa ◽  
Yellow Mosaic Virus ◽  
Field Variation ◽  
Emerging Viruses ◽  
Negative Results ◽  
Chlorotic Mottle Virus ◽  
Maize Chlorotic Mottle Virus ◽  
Chlorotic Mottle ◽  
Sub Saharan

AbstractMaize lethal necrosis disease (MLN) is an emerging disease in East Africa caused by the introduction of Maize chlorotic mottle virus (MCMV). Recent activity seeking to limit spread of the disease is reliant on effective diagnostics. Traditional diagnostics applied on samples with typical field symptoms of MLN have often given negative results using ELISA or PCR for MCMV and Sugarcane mosaic virus (SCMV). Samples collected in the field with typical MLN symptoms were examined using next generation sequencing (NGS). SCMV was found to be more prevalent than suggested by targeted diagnostics. Additionally, the panel of samples were found to be infected with a range of other viruses, seven of which are described here for the first time. Although not previously identified in the region, Maize yellow mosaic virus (MYMV) was the most prevalent virus after MCMV. The development of targeted diagnostics for emerging viruses is complicated when the extent of field variation is unknown, something that can be negated by using NGS methods. As a result we explored MinION technology which may be more readily deployable in resource poor settings. The results show that this sequencer can diagnose known viruses and future iterations have the potential to identify novel viruses.

scholarly journals Status and Epidemiology of Maize Lethal Necrotic Disease in Northern Tanzania

Pathogens ◽  
2019 ◽  
Vol 9 (1) ◽  
pp. 4 ◽  
Author(s):  
Fatma Hussein Kiruwa ◽  
Samuel Mutiga ◽  
Joyce Njuguna ◽  
Eunice Machuka ◽  
Senait Senay ◽  
...  
Keyword(s):  
Mosaic Virus ◽  
Plant Diseases ◽  
Yellow Dwarf ◽  
Dwarf Virus ◽  
Maize Dwarf Mosaic Virus ◽  
Rt Pcr ◽  
Chlorotic Mottle Virus ◽  
Maize Chlorotic Mottle Virus ◽  
Chlorotic Mottle ◽  
Yellow Dwarf Virus

Sustainable control of plant diseases requires a good understanding of the epidemiological aspects such as the biology of the causal pathogens. In the current study, we used RT-PCR and Next Generation Sequencing (NGS) to contribute to the characterization of maize lethal necrotic (MLN) viruses and to identify other possible viruses that could represent a future threat in maize production in Tanzania. RT-PCR screening for Maize Chlorotic Mottle Virus (MCMV) detected the virus in the majority (97%) of the samples (n = 223). Analysis of a subset (n = 48) of the samples using NGS-Illumina Miseq detected MCMV and Sugarcane Mosaic Virus (SCMV) at a co-infection of 62%. The analysis further detected Maize streak virus with an 8% incidence in samples where MCMV and SCMV were also detected. In addition, signatures of Maize dwarf mosaic virus, Sorghum mosaic virus, Maize yellow dwarf virus-RMV and Barley yellow dwarf virus were detected with low coverage. Phylogenetic analysis of the viral coat protein showed that isolates of MCMV and SCMV were similar to those previously reported in East Africa and Hebei, China. Besides characterization, we used farmers’ interviews and direct field observations to give insights into MLN status in different agro-ecological zones (AEZs) in Kilimanjaro, Mayara, and Arusha. Through the survey, we showed that the prevalence of MLN differed across regions (P = 0.0012) and villages (P < 0.0001) but not across AEZs (P > 0.05). The study shows changing MLN dynamics in Tanzania and emphasizes the need for regional scientists to utilize farmers’ awareness in managing the disease.

Status of Maize Lethal Necrosis Disease in Zambia

2020 ◽  
Vol 2 (1) ◽  
pp. 1-16
Author(s):  
Doreen Chomba ◽  
◽  
Msiska K. K. ◽  
Abass M. S. ◽  
Mudenda M. ◽  
...  
Keyword(s):  
Food Security ◽  
Mosaic Virus ◽  
Agricultural Research ◽  
Smallholder Farmers ◽  
Maize Dwarf Mosaic Virus ◽  
Maize Production ◽  
Chlorotic Mottle Virus ◽  
Maize Chlorotic Mottle Virus ◽  
Chlorotic Mottle ◽  
The Status

Maize is a staple food in Zambia and contributes immensely to food security for smallholder farmers. Disease outbreaks such as Maize Lethal Necrosis Disease (MLND) can be a key constraint to maize production. This disease is caused by synergistic co-infection with Maize Chlorotic Mottle Virus (MCMV) and any virus from the family Potyviridae, particularly, Sugarcane Mosaic Virus (SCMV), Maize Dwarf Mosaic Virus (MDMV) or Wheat Streak Mosaic Virus (WSMV). In 2011, an outbreak of MLND affecting almost all of the currently grown commercial varieties posed a challenge to maize production in Kenya and it has since been reported in DR Congo, Ethiopia, Kenya, Rwanda, Tanzania, and Uganda causing yield losses of up to 100%. Despite MLND having been reported in some neighboring countries, there is no information on the status of the disease in Zambia. Additionally, there is a lot of grain and seed trade between Zambia and other countries among which MLND has been reported. The aim of this study was to establish: (a) the status of MCMV; (b) agricultural practices used by farmers and (c) insect vectors associated with MLND. A survey was conducted in nine (9) provinces of Zambia during 2014/2015 and 2015/ 2016 cropping seasons. Farmers’ maize fields were sampled at every five to ten-kilometer interval and tested using rapid diagnostic kits capable of detecting MCMV. Four hundred and nineteen samples collected all tested negative for MCMV. Zambian Agricultural Research Institute (ZARI), with all stakeholders in the maize value chain should continue implementing measures aimed at preventing the introduction of MLND in Zambia. Key words: Survey, MLND, Losses, food security

scholarly journals Maize Lethal Necrosis (MLN), an Emerging Threat to Maize-Based Food Security in Sub-Saharan Africa

2015 ◽  
Vol 105 (7) ◽  
pp. 956-965 ◽  
Author(s):  
George Mahuku ◽  
Benham E. Lockhart ◽  
Bramwel Wanjala ◽  
Mark W. Jones ◽  
Janet Njeri Kimunye ◽  
...  
Keyword(s):  
Food Security ◽  
Democratic Republic Of Congo ◽  
Management Strategies ◽  
Sub Saharan Africa ◽  
Eastern Africa ◽  
Smallholder Farming ◽  
Chlorotic Mottle Virus ◽  
Maize Chlorotic Mottle Virus ◽  
Chlorotic Mottle ◽  
Sub Saharan

In sub-Saharan Africa, maize is a staple food and key determinant of food security for smallholder farming communities. Pest and disease outbreaks are key constraints to maize productivity. In September 2011, a serious disease outbreak, later diagnosed as maize lethal necrosis (MLN), was reported on maize in Kenya. The disease has since been confirmed in Rwanda and the Democratic Republic of Congo, and similar symptoms have been reported in Tanzania, Uganda, South Sudan, and Ethiopia. In 2012, yield losses of up to 90% resulted in an estimated grain loss of 126,000 metric tons valued at $52 million in Kenya alone. In eastern Africa, MLN was found to result from coinfection of maize with Maize chlorotic mottle virus (MCMV) and Sugarcane mosaic virus (SCMV), although MCMV alone appears to cause significant crop losses. We summarize here the results of collaborative research undertaken to understand the biology and epidemiology of MLN in East Africa and to develop disease management strategies, including identification of MLN-tolerant maize germplasm. We discuss recent progress, identify major issues requiring further research, and discuss the possible next steps for effective management of MLN.

scholarly journals Johnsongrass mosaic virus Contributes to Maize Lethal Necrosis in East Africa

Plant Disease ◽  
2017 ◽  
Vol 101 (8) ◽  
pp. 1455-1462 ◽  
Author(s):  
Lucy R. Stewart ◽  
Kristen Willie ◽  
Saranga Wijeratne ◽  
Margaret G. Redinbaugh ◽  
Deogracious Massawe ◽  
...  
Keyword(s):  
Mosaic Virus ◽  
East Africa ◽  
Virus Disease ◽  
Maize Dwarf Mosaic Virus ◽  
East African ◽  
Chain Reaction ◽  
Chlorotic Mottle Virus ◽  
Maize Chlorotic Mottle Virus ◽  
Chlorotic Mottle ◽  
Polymerase Chain

Maize lethal necrosis (MLN), a severe virus disease of maize, has emerged in East Africa in recent years with devastating effects on production and food security where maize is a staple subsistence crop. In extensive surveys of MLN-symptomatic plants in East Africa, sequences of Johnsongrass mosaic virus (JGMV) were identified in Uganda, Kenya, Rwanda, and Tanzania. The East African JGMV is distinct from previously reported isolates and infects maize, sorghum, and Johnsongrass but not wheat or oat. This isolate causes MLN in coinfection with Maize chlorotic mottle virus (MCMV), as reported for other potyviruses, and was present in MLN-symptomatic plants in which the major East African potyvirus, Sugarcane mosaic virus (SCMV), was not detected. Virus titers were compared in single and coinfections by quantitative reverse transcription-polymerase chain reaction. MCMV titer increased in coinfected plants whereas SCMV, Maize dwarf mosaic virus, and JGMV titers were unchanged compared with single infections at 11 days postinoculation. Together, these results demonstrate the presence of an East African JGMV that contributes to MLN in the region.

scholarly journals A first global phylogeny ofMaize chlorotic mottle virus

2017 ◽  
Author(s):  
Luke A Braidwood ◽  
Diego F Quito-Avila ◽  
Darlene Cabanas ◽  
Alberto Bressan ◽  
Anne Wangai ◽  
...  
Keyword(s):  
East Africa ◽  
Total Yield ◽  
Sub Saharan Africa ◽  
Mottle Virus ◽  
Adjusted Rand Index ◽  
Maize Production ◽  
Chlorotic Mottle Virus ◽  
Maize Chlorotic Mottle Virus ◽  
Chlorotic Mottle ◽  
Sub Saharan

ABSTRACTMaize chlorotic mottle virushas been rapidly spreading around the globe over the past decade. The interactions ofMaize chlorotic mottle viruswith potyviridae viruses causes an aggressive synergistic viral condition - maize lethal necrosis, which can cause total yield loss. Maize production in sub-Saharan Africa, where it is the most important cereal, is threatened by the arrival of maize lethal necrosis. We obtainedMaize chlorotic mottle virusgenome sequences from across East Africa and for the first time from Ecuador and Hawaii, and constructed a phylogeny which highlights the similarity of Chinese to African isolates, and Ecuadorian to Hawaiian isolates. We used a measure of clustering, the adjusted Rand index, to extract region-specific SNPs and coding variation that can be used for diagnostics. The population genetics analysis we performed shows that the majority of sequence diversity is partitioned between populations, with diversity extremely low within China and East Africa.

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