Caracterização genômica de genes de síntese de amido e elementos repetidos e suas aplicações no melhoramento genético vegetal

Abstract

The availability of plant genome sequences in public databases has allowed the development of studies that bring important understanding regarding the evolution of species. This has helped genetic improvement programs aiming at tolerance to environmental stresses that not only reduce yield, but also affect grain quality. Still, there is a lot to understand, especially regarding the evolution of repetitive sequences in accessory genomes and in genes related to grain quality in plants under abiotic stresses. Here, five studies are presented, bringing new information in those areas. The first one deals with the abundance, distribution, and evolution of microsatellites (SSRs) in plant and algae mitochondrial genomes. The results provide important insights into the evolution of SSRs in plant groups. In the other study, 26 primers are offered for the amplification of SSRs in the plastid genomes of Oat that allow the distinction of species and populations of the Avena genus. Study for rice grain quality was conducted, characterizing 19 important genes that act in the synthesis and modification of starch in 11 species of Oryza. In this study, it is suggested that amino acid deletions/mutations in active sites in wild species result in variations that can negatively affect stages of starch biosynthesis in the endosperm, which can be very useful in rice breeding programs aiming at grain quality a from wild species. Finally, a strategy was proposed, through the identification of a SNP, to be tested and used in breeding programs for tolerance to the main stresses that affect rice grain quality.