Estudo transcricional em maçãs cv. Gala durante o armazenamento

Abstract

The apple fruit is susceptible to changes in sensory attributes during post-harvest. To avoid changes in firmness the fruits are stored in refrigerated (AR) or controlled (AC) atmosphere combined with the application of 1- methylcyclopropene (1-MCP). However, it is still unclear what genes are involved in maintaining the cell wall in apples during storage. Changes in fruits during ripening are coordinated by genes encoding enzymes related to assembly and disassembly of the cell wall. The objective of the study was to evaluate the accumulation of transcripts of genes involved in the cell wall metabolism of cv. Gala during storage in RA and CA, in the presence and absence of 1-MCP. After storage the fruits were placed at 25 ° C for seven days to simulate shelf life conditions. Physical-chemical characterization, transcript and saccharide profile analyzes were performed. Fruits not treated with 1-MCP, which were stored in RA, showed a reduction in firmness and acidity. However, fruits treated with 1- MCP and stored in RA, maintained firmness and acidity, from the moment of harvest until six months of storage, as observed for fruits treated and not treated with 1-MCP, and stored in controlled atmosphere (CA). In the transcriptional analysis, six of the cell wall genes were studied (MdFLA2, MdGAUT9, MdUDP, MdAF3, MdBXL1 and MdEXGT) were studied for two harvests. In general, most of the genes studied in the presence of 1-MCP maintained the same transcriptional behavior between the crops. In contrast, in the absence of 1-MCP the transcriptional accumulation was different between the crops, mainly for the genes of cell wall biosynthesis. Among the genes studied, MdEXGT presents potential involvement in the advancement of apple maturing during storage for six months. The application of 1-MCP, as well as the choice of the storage atmosphere were important factors for the reduction of the accumulation of transcripts of this gene and for the increase of the time of sharing of the fruit.