This document discusses advance portable tools for on-site detection of plant pathogens. It covers various disease detection tools including visual observation, cultural techniques, and the Foldscope microscope. It also discusses indirect detection methods like thermography, fluorescence imaging, hyperspectral techniques, and gas chromatography. Biosensor approaches for plant pathogen detection are also presented, including antibody-based biosensors, optical immunosensors, fluorescent approaches using quantum dots, and surface plasmon resonance systems. Loop mediated isothermal amplification is also discussed as a rapid detection method. The document emphasizes the importance of early detection in plant disease management and hopes that more portable detection devices will be developed to support efficient on-site diagnosis.
10. FOLDSCOPE
Origami based print fold paper- microscope that we can build in
20 minutes
The foldscope costs less than a doller, weights 8 gm and fits in
your pockets
Invented by Manu Prakash and Jim Cybulski
11.
12. Limitations Faced due to conventional
techniques !!!!!!!
Latent infection : Potato ring rot
Misleading infection : Black lesions (Alternaria) and bacterial
blight of carrot (Xanthomonas)
Co-infection : Alteration of symptoms
13. Indirect techniques are non-invasive methods to identify plant
diseases, not through the direct identification of the pathogen, but by
detecting the impact of the pathogen on the physiological plant
response.
a) Thermography
b) Fluorescence Imaging
c) Hyperspectral Techniques
d) Gas Chromatography
Indirect Detection Methods
14. THERMOGRAPHY
Thermography allows the visualization of differences in
surface temperature by detecting emitted infrared radiation
[long-wave infrared (8–14 mm)].
Airborne sensors are suitable for the detection of field
patches that are diseased with soilborne pathogens (Hillnutter
et al 2011) or in later stages of the diseases (Mahlein et al
2012).
16. Berdugo et al 2014
Leaves inoculated with S. fuliginea had higher
MTD compared to the virus treatments and
the untreated control
17. FLUORESCENCE IMAGING
The chlorophyll fluorescence imaging can be an effective tool in monitoring leaf
diseases (Lenk et al 2007).
Chaerle et al (2007) used blue-green fluorescence to evaluate the effectiveness of this
technique in observing the development of tobacco mosaic virus (TMV) infection in
tobacco plants.
Temporal and spatial variations of chlorophyll fluorescence were analyzed for precise
detection of leaf rust and powdery mildew infections in wheat leaves at 470 nm
19. Csefalvay et al 2009
Heterogeneous distribution of FV/FM and ΦPSII in artificially inoculated leaves was
associated with the presence of the developing mycelium 3 days before the occurrence of
visible symptoms and 5 days before the release of spores.
20. HYPERSPECTRAL IMAGING
Hyperspectral imaging can be used to
obtain useful information about the
plant health over a wide range of
spectrum between 350 and 2500 nm.
Bravo et al (2003) investigated the
application of visible-NIR
hyperspectral imaging for the early
detection of yellow rust disease
(Puccinia striiformis) in winter wheat.
Also useful for the assessment of
mycotoxin producing pathogens in
maize (Del Fiore et al 2010).
Anne-Katrin Mahlein 2015
21. Trimble UX5
Key Features
Apply imagery for crop scouting
to detect pests, weeds, mineral
deficiencies, and other potential
problems in agriculture
Capture 180 acres (73 hectares)
of imagery at one inch (2.5 cm)
resolution in a single flight
Operate in crosswinds up to 37
mph (60 kph)
25. Examples of plant diseases assessed by imaging techniques
Mahlein 2016
26. GAS CHROMATOGRAPHY
Plant disease detection involves the profiling of the volatile compounds
Profiling of VOC used as a means to identify the type and nature of infection
27. Jansen et al 2011
Emission of volatile organic compounds (VOCs)
from non-infected and Botrytis cinerea–infected
tomato plants.
29. Pathogen biosensing strategies are based on biological recognition using different
receptors such as antibodies, DNA probe, phage,
Singh et al 2013
30.
31. Antibody based biosensors
Electrochemical Immunosensors - based on label-free technologies
and enzymatic label based voltammetric approaches on mercury, gold
and carbon electrodes
1. Voltammetric detection based on the use of enzymes
2. Label-free electrochemical impedance spectroscopy (EIS)- based
detection
3. Label-free quartz crystal microbalance-based approaches
32.
33. ECEIA sensor using gold nanoparticles as carriers of enzyme-labeled
antibodies for signal amplification, applied for Pantoea stewartii pv.
stewartii (PSS).
Zhao et al. (2014)
34. Optical Immunosensors
The principle of this test is based on antibody-antigen specific interaction.
The first LFIA for plant pathogen detection was designed to detect Tobacco mosaic
virus (Tsuda et al 1992).
Lateral flow microarrays
38. Fluorescent approaches
Charlermroj et al (2013)
Microsphere sandwich immunoassay technology based on fluorescence- loaded
magnetic microsphere and fluorophore-antibodies has been applied for detecting
multiple analytes such as biomarkers, food and plant pathogens
40. Quantum Dots
Fluorescence resonance energy transfer (FRET) mechanism, which
describes energy transfer between two light-reactive molecules.
Many QD-FRET-based sensors have been developed for phytoplasma
disease detection such as the witches’ broom disease of lime caused by
Candidatus aurantifolia (Rad et al 2012).
Rhizomania, which is the most destructive disease in sugar beet, is
caused by beet necrotic yellow vein virus (BNYVV) was successfully
reported to be detected by QD-FRET-based sensor (Safarpour et al
2012)
45. Loop Mediated Isothermal Amplification
(LAMP)
LAMP was reported for the
first time by Notomi et al (2000)
for the detection of the hepatitis B
virus.
The fast results and the high
specificity of the technique for
pathogen detection (Yan et al
2017).
51. Early detection of old, new and emerging infectious plant disease plays critical
role in plant disease management.
Most of reported biosensors for plant disease detection are still for use at lab level,
it is expected that more portable devices will emerge in the future being a strong
support for an efficient diagnostic.
The spectroscopic and imaging technology could be integrated with an
autonomous agricultural vehicle for reliable and real-time plant disease detection
to achieve superior plant disease control and management
Need to detect plant diseases quickly, accurately and at the right point of time before an outbreak is crucial for farmers worldwide.
Sensitive and robust technologies are required for the rapid diagnosis of pathogens in order to reduce yield losses (Yoo & Lee, 2016).
Foldscope is the ultra-affordable, paper microscope. Designed to be extremely portable, durable, and to give optical quality similar to conventional research microscopes (magnification of 140X and 2 micron resolution), Foldscope brings hands-on microscopy to new places!
Overview of surface plasmon resonance biosensor. The sensor chip is composed of a glass surface coated with a thin layer of gold that provide the physical conditions necessary for the SPR reaction. The surface of the chip is immobilized with one interacting molecule (ligand) while the other (analyte) is delivered to the surface through a microfluidic system. Polarized light is incident on the reverse side of this chip, propagating an electron charge density wave phenomenon that arises on the surface of the metallic film. This takes the form of an evanescent wave that extends beyond the sensor surface and detects mass changes on the surface. Binding of analyte to the immobilized ligand is followed by SPR, leading to detection of mass concentrations at the sensor surface. As molecules bind to and dissociate from the sensor chip surface, the resulting changes in the resonance signal create a sensorgram which is measured by a detection unit.
SPR sensor response after the interaction of different concentrations of antigen over the immobilized antibody (1: 500)
Observation
• The responses increased in proportion to the concentration of teliosporic antigen due to the change of the refractive index near the SPR sensor chip
LAMP is a PCR based technique that works with a Bst polymerase