Vegetos
(An International Journal of Plant Research & Biotechnology)
(eISSN: 2229-4473)
Exogenous salicylic acid induces GluA and PR1a defense genes and enhances tomato tolerance to combined salinity and bacterial canker stress
*Article not assigned to an issue yet
Ahmad Jawad, Abbasi Hammad Ahmed, Atif Muhammad, Ullah Sana, Jalal Abdullah, Azam Zunaira, Bibi Hafsa
Research Articles | Published: 27 August, 2026
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Keywords: n Solanum lycopersicumn , Salicylic acid, n Clavibacter michiganensis subsp. michiganensisn , Salinity stress, PR1a, ?-1,3-glucanase A (GluA), Systemic acquired resistance, Gene expression
Abstract
Tomato (Solanum lycopersicum L.) productivity is increasingly constrained by simultaneous abiotic and biotic stresses, particularly salinity and bacterial canker caused by Clavibacter michiganensis subsp. michiganensis (Cmm). This study evaluated the effects of exogenous salicylic acid (SA; 0.5 mM) on three tomato cultivars (Roma, Gala, and Rio Grande) exposed to salinity (60 mM NaCl), Cmm infection, and their combination. Growth, physiological traits, yield, and expression of the defense-related genes PR1a and GluA were assessed. Combined stress caused the greatest reductions in chlorophyll content, relative water content (RWC), vegetative growth, reproductive development, and yield. SA substantially alleviated these effects, increasing chlorophyll content and RWC under combined stress, improving plant height and branch production, and accelerating flowering and fruiting. Fruit size, number, and yield were also significantly improved by SA treatment. RT-qPCR analysis showed progressive induction of PR1a and GluA, with maximum expression at 3 days post-inoculation and the strongest response in SA-treated plants under combined stress. These findings indicate that exogenous SA enhances physiological performance while activating defense-associated pathways, supporting its potential for improving tomato resilience under concurrent abiotic and biotic stresses.
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Author Information
Institute of Biotechnology and Genetic Engineering, The University of Agriculture Peshawar, Peshawar, Pakistan