Induction of systemic resistance and defense-related enzymes in tomato plants using Pseudomonas fluorescens CHAO and salicylic acid against root-knot nematode Meloidogyne javanica

Root-knot nematodes (Meloidogyne spp.) are the most economically important group of plant parasitic nematodes on many crops worldwide. Resistance-based management is considered as one of the most sound and effective strategies against these pathogens. Plant-mediated systemic resistance against the M. javanica in tomato cv. CALJN3 was triggered using salicylic acid (SA) and Pseudomonas fluorescens CHAO as elicitors. The effect of each elicitor was assayed by (1) the calculation of nematode indices including the number of nematode galls, egg masses and eggs/egg mass; (2) the analysis of changes in the concentration of reactive oxygen species (ROS); and (3) monitoring the activities of their scavenging enzymes viz. superoxide dismutase (SOD), peroxidase (POX), and catalase (CAT). The results indicated that SA/bacterial elicitors induced the removal of high concentrations of the toxic ROS via an increase in the activity of their scavenging antioxidant enzymes, especially that of catalase. Moreover, pre- or post-treatment application of the elicitors significantly reduced the number of galls, egg masses or eggs of M. javanica in infected tomato plants as compared to the control. The results of the present study support the involvement of the elicitor-induced ROS and related scavenging enzymes for stimulating plant defense reactions in a moderately resistant tomato challenged with M. javanica

Evaluation and phylogenetic analysis of regular rabies virus vaccine strains

Background: This study aimed to evaluate Rabies virus vaccine strains. The obtained results may be helpful for vaccine producers and researchers to compare the strains with wild type and other vaccine strains and select the correct strain to challenge their products. Methods: Fourteen rabies virus vaccine strains were compared with each other. The full genomes of the selected strains were taken from the GenBank and the N, P and G genes were labeled. The major and minor antigenic sites of these sequences were identified and contrasted with each other. The identity matrix was designed for rabies virus full genome, N and G genes. In addition, the phylogenetic tree was drawn based on rabies virus N gene for deep analysis. Results: Although there were no significant differences between antigenic sites in N, P, and G genes, there were noticeable differences for full genome identity matrix and this significant difference can also be observed in N and G identity matrix. In the phylogenetic tree, the Iranian sequences were distant from currently applied vaccine strains. Conclusion: It is necessary to pay attention to the results shown in phylogenetic tree because they warn us about distance between the Iranian sequences and current strains used in applied vaccines. In addition, the obtained results help vaccine producers to choose a correct strain to challenge their product and evaluate their vaccine potency. © 2018 The Author(s)