Drought is the most damaging among the major abiotic stresses. Transcriptomic studies allow a global overview of expressed genes, providing the basis for molecular markers development. Here, the HT-SuperSAGE technique allowed the evaluation of four drought-tolerant cultivars and four-sensitive cultivars, after 24h of irrigation suppression. We identified 9831 induced unitags from roots of the tolerant cultivars with different regulations by the -sensitive cultivars after the applied stress. These unitags allowed a proposal of 15 genes, whose expressed profiles were validated by RT-qPCR, evaluating each cultivar independently. These genes covered broad metabolic processes: ethylene stress attenuation (ACCD); root growth (β-EXP8); protein degradation [ubiquitination pathway (E2, 20SPβ4); plant proteases (AP, C13)]; oxidative detoxification (TRX); fatty acid synthesis (ACC); amino acid transport (AAT), and carbohydrate metabolism [glycolysis (PFK, TPI, FBA); TCA cycle (LDP, MDH); pentose phosphate pathway (TKT)]. The expressed profiles showed a genotype-dependent regulation of the target genes. Two drought-tolerant cultivars (SP83-2847; CTC6) presented each one, nine of the induced genes. Among the -sensitive cultivars, CTC13 induced only one, while SP90-1636 induced two genes. These genes should help breeders to identify accessions managing drought stress tolerance responses, showing better ethylene stress attenuation, energy allocation, amino acid transport, and protein homeostasis.
Keywords: Abiotic stress; Bioinformatics; RT-qPCR; Saccharum spp.; Water deficit.
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