Aspectos fisiológicos e moleculares de sementes de Coffea arabica submetidas à secagem

Abstract

The low longevity of coffee seeds has been attributed to their sensitivity to desiccation. Studies related to gene expression and enzymatic activity in coffee seeds submitted to drying are important for the understanding of drying effects on the physiological quality of these seeds. The objective of this research was to study the molecular aspects of seeds submitted to different drying methods and to associate them with the physiological quality. The coffee seeds were dried slowly and rapidly with different water contents. Analysis of the enzymatic activity, as well as the expression of the transcripts of superoxide dismutase enzymes, catalase, peroxiredoxins, isocitrate lyase and endo-beta-mannanase were performed. Drying speed and final water content had a significant effect on the physiological quality, enzymatic activity, expression of the different genes analyzed and on the proteomic profile of the analyzed seeds. In seeds submitted to rapid drying, there was a greater expression of the transcripts of the genes encoding the catalase enzymes and endo -β-mannanase. Higher expression of the 1CYS PRX and SOD genes and activities of the ICL and ACX isoenzymes were verified in seeds with higher physiological quality. On the other hand, the greater activity of endo-β-mannanase and CAT enzymes occurred in seeds with lower physiological performance. In coffee seeds slowly dried up to 20 and 10% of water content, there was a higher percentage of protein spots in two-dimensional gels.