Background: Production of cassava (Manihot esculenta Crantz), a food security crop in sub-Saharan Africa, is threatened by the spread of cassava brown streak disease (CBSD) which manifests in part as a corky necrosis in the storage root. It is caused by either of two virus species, Cassava brown streak virus (CBSV) and Ugandan cassava brown streak virus (UCBSV), resulting in up to 100% yield loss in susceptible varieties.
Methods: This study characterized the response of 11 cassava varieties according to CBSD symptom expression and relative CBSV and UCBSV load in a field trial in Uganda. Relative viral load was measured using quantitative RT-PCR using COX as an internal housekeeping gene.
Results: A complex situation was revealed with indications of different resistance mechanisms that restrict virus accumulation and symptom expression. Four response categories were defined. Symptom expression was not always positively correlated with virus load. Substantially different levels of the virus species were found in many genotypes suggesting either resistance to one virus species or the other, or some form of interaction, antagonism or competition between virus species.
Conclusions: A substantial amount of research still needs to be undertaken to fully understand the mechanism and genetic bases of resistance. This information will be useful in informing breeding strategies and restricting virus spread.
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http://dx.doi.org/10.1186/s12985-014-0216-x | DOI Listing |
Insects
November 2024
Regional Center of Excellence for Transboundary Plant Pathogens, Central and West African Virus Epidemiology (WAVE), Pôle Scientifique et d'Innovation, Université Félix Houphouët-Boigny, Abidjan BPV 34, Côte d'Ivoire.
Whitefly (Gennadium, Hemiptera) causes severe damage to cassava plants through excessive feeding on leaves and transmitting viruses, such as (ACMV), (EACMV), and ipomoviruses that cause cassava brown streak disease. Currently, little is known about the molecular diversity and distribution of whitefly species in the major cassava-growing zones of Nigeria. This study aimed to address the knowledge gap by assessing the genetic diversity, distribution, and associated cassava mosaic begomoviruses (CMBs) in whiteflies across South West and North Central, Nigeria.
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November 2024
Department of Botany and Microbiology, College of Science, King Saud University, P.O. Box- 2455, Riyadh 11451, Saudi Arabia.
Edible, eco-friendly films made from cassava starch, cinnamon essential oil (CEO), and fish gelatin have been shown to extend the shelf life of fish fillets. These biodegradable films offer an environmentally friendly alternative to conventional plastic packaging. This study explores the production of edible films using cassava starch, fish gelatin from processing waste, and CEO nanoemulsion (CEON), focusing on their physical, mechanical, antioxidant, and antibacterial properties.
View Article and Find Full Text PDFSci Rep
October 2024
International Center for Tropical Agriculture, CIAT, Palmira, 6713, Colombia.
Cassava (Manihot esculenta Crantz) is a vital carbohydrate source for over 800 million people globally, yet its production in East Africa is severely affected by cassava brown streak disease (CBSD). Genebanks, through ex-situ conservation, play a pivotal role in preserving crop diversity, providing crucial resources for breeding resilient and disease-resistant crops. This study genotyped 234 South American cassava accessions conserved at the CIAT genebank, previously phenotyped for CBSD resistance by an independent group, to perform a genome-wide association analysis (GWAS) to identify genetic variants associated with CBSD resistance.
View Article and Find Full Text PDFFront Plant Sci
September 2024
Tissue culture and Transformation Laboratory, National Crops Resources Research Institute (NaCRRI), Kampala, Uganda.
Cassava () production and productivity in Africa is affected by two viral diseases; cassava mosaic disease (CMD) and cassava brown streak disease (CBSD). Induced mutagenesis of totipotent/embryogenic tissues or plant material can lead to the generation of CMD and/or CBSD tolerant mutants. To massively produce non-chimeric plants timely and with less labor, totipotent cells or tissues are a pre-requisite.
View Article and Find Full Text PDFViruses
September 2024
International Institute of Tropical Agriculture (IITA-Tanzania), Dar es Salaam P.O. BOX 34441, Tanzania.
Cassava is an important food crop in western Kenya, yet its production is challenged by pests and diseases that require routine monitoring to guide development and deployment of control strategies. Field surveys were conducted in 2022 and 2023 to determine the prevalence, incidence and severity of cassava mosaic disease (CMD) and cassava brown streak disease (CBSD), whitefly numbers and incidence of cassava green mite (CGM) in six counties of western Kenya. Details of the encountered cassava varieties were carefully recorded to determine the adoption of improved varieties.
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