A comparative molecular analysis of two genotypes of Solanum lycopersicum in respect of the expression of selected salt responsive genes in leaves and roots

Plant salt tolerance is a complex trait controlled by multiple genes. In recent years, considerable attention has been directed toward elucidating the molecular basis of plant salt tolerance, and numerous salt related genes have been identified. High salinity is one of the most serious threats to crop production. To understand better the molecular basis of plant responses to salt stress, a comprehensive knowledge of the up-and down-regulating genes under salt stress is necessary. Solanum lycopersicum is a moderately salt tolerant crop species with considerable economic importance in salinity affected arid and semi-arid regions of the world. In this study, the tomato cultivars “Pusa Ruby” (PR) and “Punjab Keshari” (PK) were used for transcriptional profiling under salinity stress (200 mM NaCl for 6 h), using semi-quantitative RT-PCR. The experiment was designed to target ten defense related genes in roots and leaves of two-month-old plants. A comparable transcript expression profile of up-regulated and down-regulated genes has been created in two different varieties of tomato, in response to salinity. The study confirmed that transcriptional responses differed in leaves and roots, indicating that the molecular mechanisms for responses to the stress in tomato leaves were distinct from those in the roots. Our results revealed a differential expression of all the targeted genes under study in both cultivars of tomato. A higher level of expression of stress responsive genes in PK leaves in comparison to PR leaves, together with a much higher basal expression of the targeted genes targeted in our study suggested a more effective defense system in PK.