Detection of Plant Pathogens by using Nano-technology

              Nanotechnology   is   manufacturing   at   the   molecular   level-   building   things   from Nano-scale components.   Nanotechnology proposes the construction   of novel Nano-scale devices   possessing   extraordinary   properties.   Through   the   developments   of   such instruments   and  technique   it   is   becoming   possible   to   study   and   manipulate   individual atoms.

Nanosized metals as diagnostic probes

              Nanoparticles are different from their bulk counterparts, which, when reduced to nanosize (1-100 nm) achieve certain properties which make them suitable for development as diagnostic probes (Sharon et al., 2010). These properties are large aspect ratio (surface to volume ratio), chemically alterable physical properties, strong affinity to target (particularly of gold nanoparticles to proteins), structural sturdiness in spite of atomic granularity and enhanced or delayed particles aggregation depending on the type of the surface modification, enhanced photoemission, high electrical and heat conductivity and improved surface catalytic activity (Shrestha et al., 2007).

              Fluorescent silica nanoprobes have potential for rapid diagnosis of plant diseases. Fluorescent silica nanoprobes conjugated with the secondary antibody of goat anti-rabbit IgG (Yao et al., 2009) was used for detection of a bacterial plant pathogen Xanthomonas axonopodis pv. Vesicatoria (bacterial spot on solanaceous plants). An organic dye tris-2, 2' -bipyridyl dichlororuthenium (II) hexahydrate (Rubpy) was incorporated into the core of circular silica nanoparticles with average diameter of 50 ± 4.2 nm. Thus silica nanoparticles became fluorescent which was photostable.

Nanoscale biosensor/ nanosensors

              The nanosensors which would be small and portable would provide rapid response and real-time processing with accurate, quantitative, reliable, reproducible, robust, specific and stable results. Detection of infection in non-symptomatic plant followed by targeted delivery of treatment would be an essential component for precision farming. Use of micromechanical cantilever arrays for detection of fungal spore (Aspergillus niger and Saccharomyces cerevisiae) was demonstrated by Nugaeva et al. (2005).

Quantum dots

              “QDs are few nm in diameter, roughly spherical (some QDs have rod like structures), fluorescent, crystalline particles of semiconductors whose excitons are confined in all the three spatial dimensions”. QDs have emerged as important tool for detection of a specific biological marker in medical field with extreme accuracy. They have been used in cell labelling, cell tracking, in vivo imaging and DNA detection (Sharon et al., 2010). 

Carbon nano material as a sensor

              Carbon nanomaterials have been developed to act as electrode for electrochemical analysis (Sharon and Sharon, 2008). They have the potential to be developed as electro chemical sensor to detect pesticide residue in plants.

Nanofabrication

              Nanofabrication techniques have been used in creating artificial plant parts such as stomata and xylem vessel which are then used to study the infection process and behaviour of pathogens inside host plant for example Uromyces appendiculatus (fungus causing rust disease of bean), Colletotrichum graminicola (fungus causing anthracnose in corn) and Xylella fastidiosa (xylem limited bacterium causing Pierce’s disease of grapevine) (Meng et al., 2005). In other words, it would help formation of proper breeding strategy to screen for or to develop disease resistant crop plants.

Smart’ delivery

              An interesting and fascinating area of nanoparticles is ‘smart’ or targeted drug delivery in the biological system. Gonza´lez-Melendi et al.(2008) was the first to report the penetration and transport of nanoparticles inside whole plant. These results indicate the possibility and potential of nanoparticles in delivery of substances inhibitory to various plant pathogens.

Conclusion:

By using Nanotechnological techniques on hard core basis we can arrest the loses caused due to plant diseases by diagnosing diseases before their occurrence or symptoms expression.

REFERECES:

M. R. Khan and T. F Rizvi, 2014.  Nanotechnology: Scope and application in Plant Disease      Management, Pl. Pathol. J. 13(3) : 214-231

Banik, S. and P. Sharma, 2011. Plant Pathology in era of nanotechnology. Indian      Phytopathol, 64(2) :120-127.

Article compiled by Mr. Amol Vijay Shitole (Ph.D. Scholar)

Dr. Panjabrao Deshmukh Krishi Vidyapeeth, Akola (M.S.)