<p>Drug-delivery nano-systems enhances the potency of bioactive
molecules due to its increase membrane permeability, as a result of their
sub-cellular size. The concept of engineered nano-carriers may be a promising
route to address confounding challenges in agriculture that could lead to an
increase in crop production while reducing the environmental impact associated
with crop protection and food production. A key motivation of this work is to
evaluate the potential use of drug delivery nanosystems in agriculture,
especially in the area of disease control. To this end, identifying the most
suitable materials to serve as carrier and cargo is imperative. Understanding
their bioactive properties and their physical-chemical characteristics is
critical because these influences not only their biological effects on plants
and environmental impact, but also, the fabrication process and potential
scaling-up, enabling practical and relevant field applications in the future. </p>
<p> </p>
<p>In this work, chitosan was selected as nano-carrier material
because of its biological and chemical properties. The chemical structure of
chitosan allows spontaneous assemble of core-shell like nanostructures via
ionic gelation, has enabled it to be used as nano-carrier biomaterial intended
for delivery of bioactive cargo. In agriculture, the use of chitosan is of
special interest due to its immune-modulatory activity elicited in plants.
However, due to its inherent molecular heterogenicity, the formulation and
fabrication of stable and low inter-batch variability chitosan nanocarriers via
ionic gelation is difficult and time consuming.</p>
<p> </p>
<p>A myriad of different bioactive molecules has been tested as
payload, encapsulated into chitosan-based delivery nano-systems for a range of purposes
ranging from biomedicine, pharmaceutical, food and agriculture. In this work
plant derived essential oils were selected as bioactive payload. Essential oils
are at the core of the plant communication process with their phytobiome,
including plant pathogens. Molecules from essential oils can carry an air-borne
message serving as a plant-to-plant communication system (a phenomenon known as
allelopathy) that activate the plant defense mechanisms. Encapsulation of
essential oils into chitosan nanocarriers is only possible by forming
nano-emulsions. </p>
<p>Despite the potential benefits from the use of chitosan and
essential oils in agriculture, its use at a large scale has been hindered by
the overwhelming inconsistencies in the current literature, regarding their
formulation and fabrication. This work addresses these problems and presents
evidence that support the feasibility of producing highly chitosan nanocarriers
loaded with essential oils, in a facile and rapid way, using FDA-grade
materials only, without the need of expensive or specialized instrumentation. </p>
<p> </p>
<p>The plant-pathogen compatible interaction between <i>A.
thaliana</i> and <i>B. cinerea</i> was used as biological model to test the
hypothesis that chitosan nano-carriers and essential oil nano-emulsions can
enhance the quantitative disease resistance of plants against broad host-range
necrotrophic pathogens. We found that these treatments display a dose-dependent
response in plants triggering a systemic immune response. Image-based
phenotyping analysis showed that chitosan nanoparticles alone, as well as
loaded with d-limonene, significantly enhanced the disease resistance of <i>A.
thaliana</i> against <i>B. cinerea</i>. Nano-emulsions using essential oils
from cinnamon, clove, coriander and red thyme also produced similar effects on
the defense response in the pathosystem under study. Functional analysis of the
differentially expressed genes from treated plants revealed that these
treatments up-regulated the biological process involved in “stress management”,
while down-regulated the biological process required for normal growth and
development during ideal, non-stressful conditions.</p>
| Identifer | oai:union.ndltd.org:purdue.edu/oai:figshare.com:article/13365983 |
| Date | 14 December 2020 |
| Creators | Pablo Vega (9760526) |
| Source Sets | Purdue University |
| Detected Language | English |
| Type | Text, Thesis |
| Rights | CC BY 4.0 |
| Relation | https://figshare.com/articles/thesis/DRUG_DELIVERY_NANOSYSTEMS_AS_PLANT_VACCINES_FABRICATION_AND_ASSESSMENT_OF_THEIR_USE_FOR_PLANT_PROTECTION_AGAINST_BROAD_HOST-RANGE_NECROTROPHIC_PATHOGENS/13365983 |
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