Agriculture Reference
In-Depth Information
there is a huge scope in using nanoparticles for transgene delivery in plant cells re-
sulting in transgenic plants with novel properties, such as disease resistance, stress
resistance, drought tolerance, etc.
The application of fluorescent labeled starch-nanoparticles as plant transgenic
vehicle, was reported in which the nanoparticle biomaterial was designed in such
a way that it binded the gene and transported it across the cell wall of plant cells
by inducing instantaneous pore channels in cell wall, cell membrane and nuclear
membrane with the help of ultrasound (Jun et al.
2008
). It is possible to integrate
different genes on the nanoparticle at the same time and the imaging of fluores-
cent nanoparticle is possible with fluorescence microscope, thus understanding the
movement of exterior genes along with the expression of transferred genes. Hence,
successful generation of pores on cell wall and cell membrane by suitable agents,
helps in nanoparticle mediated DNA transfer that might be more successful in re-
generative calli and soft tissues.
Dendrimers are synthetic polymers with highly symmetric architecture in which
their well-defined structures and high ratios of multivalent surface moieties to mo-
lecular volumes, make them highly suitable to function as vectors for gene and drug
delivery. Several publications have reported the successful use of these specialized
nanoparticles as drug delivery system in medicine, however their use for direct
and non-invasive gene transfer in plants has been a novel idea. It was reported that
polyamidoamine (PAMAM) dendrimer acts as a nanocarrier for delivering genes
into plant cells with intact cell wall. Supramolecular complexes of PAMAM den-
drimer-DNA are formed through electrostatic interactions and these complexes are
penetrated through the cell walls of turf grass calli, expressing foreign genes within
the cells (Pasupathy et al.
2008
).
Surface functionalized mesoporous silica nanoparticles (MSNs) provide new
ways to precisely manipulate gene expression at single cell level by delivering DNA
and its activators in a controlled fashion (Torney et al.
2007
) by penetrating through
plant cell wall (Fig.
10.3
). MSNs are loaded with gene and its chemical inducer and
the ends are capped with gold nanoparticles to protect the molecules from leaching
out. Uncapping of capping agents results in stimuli responsive release of chemicals,
thus triggering gene expression in plants. It is found that surface modification of
MSNs with triethylene glycol promotes their easy penetration into cells and also al-
lows plasmid DNA to absorb on MSN surface. In this method, the minimum amount
of DNA required to detect marker expression is 1000-fold less than that required
for the conventional delivery method and such delivery method has significant ap-
plications in various gene expression studies. Such nanoparticle-mediated plant
transformation allows site-targeted simultaneous delivery of both DNA and effector
molecules. Future possibilities include enlargement of pore size and multifunction-
uncapped by incubating the plant cells with dithiothreitol (DTT). This releases the β-estradiol
effector molecules and activates the expression of plasmid DNA in the nucleus. Surface function-
alized MSNsare successfully used for the intracellular-controlled release of genes and chemicals
into plant cells. This will help in the future investigations of plant genomics and gene function as
well as improvement of crops. (Adopted from Torney et al.
2007
)
