Abstract
Different abiotic stresses recruit dedicated signaling and regulatory genes in plants. Genome-wide stress-specific biomarkers were investigated in tomatoes. Three major abiotic stresses were compared: drought, heat, and salinity. For each stress type, 2 different tomato lines were included: susceptible and tolerant. Gene expression was examined by hybridizing to an available tomato microarray. Several stress responsive genes were upregulated in tolerant as well as in susceptible lines for each stress. Comparative analysis of gene expression in response to stress (drought, heat, or salinity) resolved a number of common biomarkers, while other groups of putative biomarkers were associated with each abiotic stress. MYB transcription factors, SAUR family proteins, and NAC domain proteins were among the highly upregulated genes under drought, while both proteinase inhibitors and heat shock proteins were prominent in the heat-tolerant line. For salinity stress, the expression of phosphate starvation-induced proteins was observed. Putative abiotic stress biomarkers can be utilized in breeding programs to improve the selection process and to aid in gene stacking.