Advances in Nanotechnology as a Potential Alternative for Plant Viral Disease Management.

Plant viruses cause enormous losses in agricultural production accounting for about 47% of the total overall crop losses caused by plant pathogens. More than 50% of the emerging plant diseases are reported to be caused by viruses, which are inevitable or unmanageable. Therefore, it is essential to devise novel and effective management strategies to combat the losses caused by the plant virus in economically important crops. Nanotechnology presents a new tendency against the increasing challenges in the diagnosis and management of plant viruses as well as plant health. The application of nanotechnology in plant virology, known as nanophytovirology, includes disease diagnostics, drug delivery, genetic transformation, therapeutants, plant defense induction, and bio-stimulation; however, it is still in the nascent stage. The unique physicochemical properties of particles in the nanoscale allow greater interaction and it may knock out the virus particles. Thus, it opens up a novel arena for the management of plant viral diseases. The main objective of this review is to focus on the mounting collection of tools and techniques involved in the viral disease diagnosis and management and to elucidate their mode of action along with toxicological concerns.

Molecular and functional characteristics, growth promoting effect and persistence of selected parent isolates and streptomycin resistant derivatives of rice rhizobacteria.

Molecular and functional characteristics of seven azospirilla and five phosphorus solubilizing bacteria (PSB) isolates of rice rhizosphere, growth promotion ability of two efficient strains, Azospirillum amazonense A10 (MTCC4716) and Bacillus megaterium P5 (MTCC4714) and their persistence based on streptomycin resistant derivatives (SRD), were determined. SDS-PAGE and isozyme banding patterns of the isolates were used to arbitrarily group the azospirilla into 4 and PSB into 3 clusters and as markers to ascertain their identity. The azospirilla produced 2.0 to 10.5 ppm of IAA like substances and showed nitrogenase activity of 0.02 to 3.55 nmole C2H4/hr/ml of pure culture. PSB isolates produced 7.8 to 15.0 ppm IAA like substances and 20 to 128 ppm soluble P. Induction of resistance to streptomycin resulted in changes of these properties. Co-inoculation of rice with SRD A10 and SRD P5 and their parental strains in separate treatments enhanced grain yield over control by 31 and 12.4%, respectively. Nitrogenase activity of rice roots under SRD co-inoculated treatment was higher (4.16 nmole C2H4/hr/hill) than that-under parental strains co-inoculated treatment (3.76 nmole C2H4/hr/hill). SDS-PAGE profile and population count of the strains confirmed their establishment in rice rhizosphere and persistence over a year after inoculation.