Publication: Effect of Biological Control Antagonists Adsorbed on Chitosan Immobilized Silica Nanocomposite on Ralstonia solanacearum and Growth of Tomato Seedlings
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2016-01-11
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JKUAT
Publisher
SCIENCEDOMAIN international
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Abstract
Background: Biological control holds promise in managing bacterial wilt disease. However, its
efficacy is limited by harsh environmental conditions when applied without use of suitable carrier
materials.
Aim: The study entailed synthesis of nanocarrier materials for biological control agents (BCAs)
using Chitosan and silica nanocomposites.
Site and Duration: The experiments were carried out at Jomo Kenyatta University of Agriculture
and Technology for a period of two years June 2013 to June 2015.
Methodology: The experiments were conducted using a completely randomized design with three
replications. Deacetylation, functionalization and immobilization of chitin on mesoporous silica
nanoparticles (MSN) to form chitosan immobilized silica nanocomposites (CISNC) gel was done.
Results: This resulted in formation of chitosan nanoparticles and CISNC with crystallite sizes of 2.8
and 4.4 nm respectively. BCAs were adsorbed on CISNC gel. Characterization of the bio-
nanocomposites showed that they had physisorption properties thus, ideal carriers for BCAs.
CISNC gel had the highest significant (P=.05) sorption properties with 75% and 65% adsorption
and desorption respectively of BCAs. Efficacy trials were done by in vitro pathogen inhibition and
greenhouse bioassays using tomato seedlings. Adsorption of BCAs on CISNC gel significantly
(P=.05) increased inhibition efficacy of BCAs on R. solanacearum from 50 to 70%. This was
attributed to the antibacterial effect of the individual substances and the overall synergy acquired.
Further, BCA-CISNC gel forms a film around root hairs, initiates fast wound healing mechanism
and induce prophylactic effect on tomato seedlings challenged with R. solanacearum pathogen,
decreasing wilting incidences from 45 to 25%. Additionally, BCA-CISNC complex significantly
(P=.05) increased tomato seed germination from 70 to 80% and growth rate from 12 to 15% due to
enhanced water utilization efficiency, induced phytohormones and nutritional benefit. BCAs also
aided faster nutrient release, absorption and utilization by tomato plants.
Conclusion: Therefore, adsorption of bacterial, fungal and phage biocontrol agents on CISNC gel,
a complex hitherto not reported to have been used in R. solanacearum disease control, enhanced
microbial efficacy against the pathogen and increased tomato productivity.
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Article
Keywords
Bacterial wilt, Lycopersicon esculentum L., sorption, microbial antagonists’ efficacy, synergy, elicitation.
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https://scholar.google.com/scholar?hl=en&as_sdt=0%2C5&q=Effect+of+Biological+Control+Antagonists+Adsorbed+on+Chitosan+Immobilized+Silica+Nanocomposite+on+Ralstonia+solanacearum+and+Growth+of+Tomato+Seedlings&btnG=#d=gs_cit&t=1718960661905&u=%2Fscholar%3Fq%3Dinfo%3Afm4Tqx1gUXAJ%3Ascholar.google.com%2F%26output%3Dcite%26scirp%3D0%26hl%3Den
https://repository.nrf.go.ke/handle/123456789/887
https://repository.nrf.go.ke/handle/123456789/887