Qualidade fisiológica e expressão de proteínas resistentes ao calor em diferentes estádios de desenvolvimento de sementes de milho

Abstract

Seeds have some mechanisms of dissection tolerance such as the expression of heat resistant proteins. The understanding of gene expression of these proteins in maize seeds is important for the technologies development which ensures the production and seeds marketing with high quality. In the present study the aim was to quantify and characterize the expression pattern of heat resistant proteins during development maize seeds of different genotypes in relation to tolerance to high drying temperature. For this purpose, in a first step was conducted pre-test with seeds from line 57, in two development stages (LL3 and LL5), evaluating the presence of heat resistant proteins, by electrophoresis technique in different parts of the seeds: embryo axis, endosperm, embryo and whole seed. Increased expression of heat resistant proteins was observed in the embryo and seeds harvested in stage LL5. In the second step was installed on field for the inbreds seeds multiplication, and two with high and two with low heat resistance. The seeds harvest was made in the development stages: LL1, LL2, LL3, LL4, LL5 and seeds were submitted to test of water content, germination, first germination count, accelerated aging and cold test. For expression analyze of heat resistant proteins using the techniques in real-time PCR, electrophoresis and spectrophotometry the seeds were stored in deep frezer until perform the analyzes. It was observed that: heat resistant proteins are expressed differentially in genotypes and development stages different; the expression of heat resistant proteins, detected by electrophoretic techniques is earlier in inbreds tolerant to high drying temperatures; higher germination values and vigor occur in seeds harvested at development stage LL5; increased expression of heat resistant proteins was observed in embryos of maize seeds.