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.