Expressão de genes relacionados à tolerância à baixa temperatura de germinação em sementes de milho

Abstract

It is known that during the seed germination and seedling emergence the temperature is a decisive factor influencing the seedling establishment in the field. So, cultivars tolerant to low temperatures in these phases are fundamental in breeding programs. The identification of importance genes, which may be used or manipulated in breeding programs envisaging the production of corn seeds tolerant to cold stress. Therefore, this study aimed to characterize corn strains tolerant to cold during the germination process by physiological tests, fatty acid profile, transcriptomic and proteomic. To carry out the work seed strains with different levels of tolerance and low temperatures were used, with three classified as tolerant and three classified as susceptible to low temperatures of germination. To obtain material in sufficient quantity to perform the work, was installed a field for seed multiplication of selected strains. After the collected and sorted seeds, it was held, physiological tests, and analysis of fatty acids were determined the levels of palmitic, stearic, oleic, linoleic, linolenic and eicosenoico. In proteomic analysis was evaluated the protein expression heat to resistant, catalase, peroxidase, esterase, superoxide dismutase and α-amylase. In the transcripts analysis was studied the expression of AOX1, AOX2, ZmMPK-17 and ZmAN-13. It can be concluded that the most susceptible materials at low temperatures of germination showed higher levels of saturated fatty acids. The α-amylase expression in seeds imbibed for 72 hours at a temperature 10 °C is lower than the expression when the seeds are imbibed at 25 °C by the same period of time. There is expression variation of the proteins resistant to heat in seeds of the tested strains. The genes AOX and Zm-AN13 showed promise for identifying corn materials tolerant to low temperature germination.