Detection and Stability Assessment of Maize Chlorotic Mottle Virus in Maize Seeds in Kenya
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Date
2023-10
Authors
Shango, Peter
Journal Title
Journal ISSN
Volume Title
Publisher
Kenyatta University
Abstract
Viral diseases, particularly Maize chlorotic mottle virus (MCMV) co-infecting with
potyviruses causes Maize lethal necrotic disease (MLND), which is a major hurdle in maize
production and a threat to food security in Africa. Maize lethal necrotic disease, spread by
thrips, threatens Sub-Saharan Africa's maize yield and trade. In Kenya, where maize is
crucial, controlling MLND has gained importance. Kenya Plant Health Inspectorate
Services (KEPHIS) tests seeds to prevent virus-causing MLND, safeguarding the market
and reducing losses for farmers and seed companies due to MCMV contamination. This
research aimed at finding ways through which diseased seed lots could be saved by either
inactivating the MCMV thermally or quarantining the seed for a particular duration during
which MCMV could inactivate. Forty samples each comprising 400 seeds of infected seed
lots were used during the experiments and subjected to different treatments. Thesc included
different temperatures, storage time, and assessment of germination capacities after the
exposure to different temperatures and times of storage. Extraction of Ribose nucleic acid
(RNA) from 400 maize seedlings which were planted per each sample was carried out using
the Cetyltrimethyl Ammonium Bromide (CTAB) method and the three testing methods
Enzyme-Linked Immunosorbent Assay (ELISA), Loop-mediated isothermal amplification
(LAMP), and Quantitative Polymerase chain reaction (q-PCR) were feasibly analyzed for
their sensitivity as well as achieving other objectives. Analysis of Variance (ANOVA) was
done by use of SAS. Results showed that MCMV Joad in maize seeds significantly reduced
with storage (p=0.001). An increase in temperature to 40°C led to a significant decrease in
MCMYV load but with a corresponding reduction in the viability of the seeds. The results
from Loop-mediated isothermal amplification (LAMP) showed the best sensitivity in
MCMYV detection up to dilution factor of 10°%, followed by real-time PCR which was
sensitive up to dilution factor 10* and, lastly, the ELISA which was sensitive up to 10% In
conclusion, the study demonstrates that MCMYV infected maize seeds can be stored for up to
three years without a significant loss in seed viability. However, it is imperativeto avoid
high temperatures, such as 40°C, during storage, as they can negatively impact seed quality.
This information is crucial for policy makers in developing effective disease management
strategies. Seed merchants can use this knowledge to ensure seed quality and avoid
cconomic losses, while farmers can benefit from understanding the appropriate storage
conditions for MCMYV infected seeds to manage the virus effectively while preserving seed
viability. Additionally, the routine use of Loop-mediated isothermal amplification (LAMP)
and real-time PCR techniques for MCMV detection is recommended.
Description
A Thesis Submitted in Partial Fulfillment of the Requirement for the Award of the Degree of Masters of Science in Crop Protection (Plant Pathology Option) in the School of Agriculture And Environmental Sciences, Kenyatta University, October, 2023
Keywords
Detection and Stability Assessment, Maize Chlorotic Mottle Virus, Maize Seeds, Kenya