ANÁLISE METABOLÔMICA POR RMN E QUIMIOMETRIA DE CANA-DE-AÇÚCAR (SACCHARUM spp.) SOB DÉFICIT HIDRÍCO E GENETICAMENTE MODIFICADA PARA SUPEREXPRESSÃO DO GENE NPK1

Abstract

The low water availability during certain periods of sugarcane cultivation negatively impacts its productivity, and the global demand for the biofuel ethanol requires strategies to mitigate these factors. One alternative is the development of varieties that are more drought-tolerant. In this context, the NPK1 gene (Nicotina protein kinase 1), derived from tobacco (Nicotiana tabacum L.), has shown promise in other cultivars under water stress conditions, as its gene overexpression initiates initiates a metabolic cascade of proteins activated by MAPKs (mitogen-activated protein kinase). Thus, this study aimed to use 1H Nuclear Magnetic Resonance (NMR) in the metabolomic analysis of leaves from genetically modified sugarcane (Saccharum officinarum) with NPK1 gene overexpression. Transgenic plants were created by IDR (GUERZONI, 2015) using two genetic transformation methods, via Agrobacterium tumefaciens (AGRO) and biolistic (CV) and compared with conventional plants (CONT). The plants were subjected to cumulative water deficit intervals (T0 to T4) and rehydrated (T5). Leaves were collected and subjected to 1H NMR analyses associated with chemometric techniques, allowing the investigation of metabolites present in leaves from aqueous and methanolic extracts.The results indicated that the main source of variation was the level of water stress, and metabolic pathway investigations revealed that different genotypes primarily activate different metabolic pathways. The CONT genotype proved to be more susceptible to the onset of stress, while the AGRO plants stood out for their tolerance at the beginning and distinct metabolic recovery after rehydration, the latter observation being related to indications of the lignification process in the leaves. The CONT genotype showed the presence of antioxidants (DAC and APGG) and amino acids, while the CV genotype utilized primary and specialized metabolites (triacylglycerides - TAG, amino acids, and antioxidants - Trigonelline and APGG), and the AGRO genotype mainly activated primary metabolites (TAG and sugars) as a defense mechanism, giving it greater tolerance to water deficit.