Salicylic acid-mediated enhancement of resistance in tomato plants against Xanthomonas perforans.

Introduction: Bacterial spot disease of tomato was identified a few decades ago. The varying point of entry for the pathogen has enhanced the complexities for designing an effective disease management method. Recent advances in the use of inducers to elicit immune response in order to prepare the plant for a future attack by the pathogen are similar to the vaccination that is undertaken in humans and is a trending technology. Objectives: The present study aims at understanding the effect of salicylic acid (SA) for management of bacterial spot disease caused by Xanthomonas perforans. Methods: The study evaluated the effects of SA on the disease incidence along with seed germination and seedling vigor in two cultivars of tomato namely, Sun hybrid- resistant variety (R) and Quality- highly susceptible variety(HS). Results: The germination and seedling vigor, which was reduced in case of HS variety in comparison with that of the R variety, was notably improved after seed priming in both the cultivars. The antioxidant enzyme activities of ascorbate peroxidise (APx), catalase (CAT) and glutathione reductase (GR) were assessed which showed that the R variety reached maximum activity at 18 h post inoculation (hpi), 24 hpi and 21 hpi, respectively, whereas the HS variety reached maximum at 30 hpi for APx and 36 hpi for CAT and GR activities. The transcript accumulation using qRT-PCR was also evaluated showing mRNA accumulation was maximum in the R cultivar after SA priming at 1.5 mM concentration. Conclusion: the present study demonstrates the potential benefits of seed priming with SA to effectively elicit defence response in tomato seedlings against the bacterial spot disease.

Phyto-Mediated Synthesis of Silver Nanoparticles Using Terminalia chebula Fruit Extract and Evaluation of Its Cytotoxic and Antimicrobial Potential.

The increasing interest in developing potent non-toxic drugs in medicine is widening the opportunities for studying the usage of nanostructures in the treatment of various diseases. The present work reports a method for a facile and an eco-friendly synthesis of silver nanoparticles (AgNPs) using Terminalia chebula fruit extract (TCE). The obtained AgNPs was characterized by using different spectroscopic and microscopic techniques. The analysis of the results revealed that the as-obtained AgNPs have spherical morphology with an average diameter of 22 nm. Furthermore, the preliminary bioactivity evaluations revealed that the bio-conjugation of AgNPs, using TCE, significantly enhanced the antibacterial and anti-breast cancer potentials of the latter. The antibacterial activity of the as-prepared AgNPs showed that B. subtilis was more sensitive towards the AgNPs, followed by P. aeruginosa; while, E. coli and S. mutans showed comparatively minimal sensitivity toward the AgNPs. The IC50 values of TCE, AgNPs and TCE + AgNPs treatment of MCF-7 were found to be 17.53, 14.25 and 6.484 µg/mL, respectively. Therefore, it can be ascertained that the bio-conjugation may provide a headway with regard to the therapeutic employment of T. chebula, upon mechanistically understanding the basis of observed antibacterial and anticancer activities.

Growth kinetics and immune response of chimeric foot-and-mouth disease virus serotype 'O' produced through replication competent mini genome of serotype Asia 1, 63/72, in BHK cell lines.

Regular vaccinations with potent vaccine, in endemic countries and vaccination to live in non-endemic countries are the methods available to control foot-and-mouth disease. Selection of candidate vaccine strain is not only cumbersome but the candidate should grow well for high potency vaccine preparation. Alternative strategy is to generate an infectious cDNA of a cell culture-adapted virus and use the replicon for development of tailor-made vaccines. We produced a chimeric 'O' virus in the backbone of Asia 1 and studied its characteristics. The chimeric virus showed high infectivity titre (>10(10)) in BHK 21 cell lines, revealed small plaque morphology and there was no cross reactivity with antiserum against Asia 1. The virus multiplies rapidly and reaches peak at 12h post infection. The vaccine prepared with this virus elicited high antibody titres.