Understanding plant response to salinity, one of the major abiotic stresses, provides insights into the improvement of tomato salt tolerance. This work focuses on the responses of tomato cultivars to salt stress. Genotypes, representative of content and enzyme activities. QPCR analysis of WRKY, ERF, LeNHX and HKT genes was also performed. A high K+, Ca2+ and proline accumulation as well as a decrease in Na+ concentration mediated salt tolerance. Concomitant with a pattern of high antioxidant enzyme activities, tolerant genotypes also displayed differential patterns of gene expression.

Salt stress was applied to tomato commercial genotypes to study adverse effects on their phenotypic traits. Three were saline tolerant (San Miguel, Romelia and Llanero), two were mildly tolerant (Perfect peel HF1 and Heinz 1350) whereas the remaining were sensitive. Genotyping cultivars using 19 polymorphic SSRs out of 25 tested produced a total of 70 alleles with an average of 3.68 alleles per locus and PIC values ranging from 0.22 (SSR 26, 92, 66 and TG35) to 0.82 (SSR 356). Principal component analysis (PCA) showed two contrasting panels discriminating tolerant and sensitive groups and one panel with scattered genotypes. STRUCTURE analysis clustered genotypes within three groups in accordance with their salt stress behavior. The success of tomato salt-tolerance breeding programs can be enhanced through molecular characterization of diversity within commercial cultivars that adapt differently to stress conditions. To this end, we combined phenotypes and SSR marker-genotypes to seek sources of salt tolerance that might be tomato species-specific. We integrated and represented genotype-phenotype associations from multiple loci into a multi-layer network representation. It is a systemic view linking discriminating genotypes to salt stress phenotypes, which may guide strategies for the introgression of valuable traits in target tomato varieties to overcome salinity.

No abstract

No abstract