Fenotipagem e análise de expressão gênica em resposta a germinação pré-colheita em trigo

Abstract

Wheat (Triticum aestivum L.) is a cereal of great economic importance, since it is the raw material for many products in the food industry. One of the factors that negatively affect field-level culture is pre-harvest twinning, reducing grain yield and quality, to the point of reducing its commercial value and making it unfeasible for human consumption. In this way, this work aimed to phenotype and analyze the expression of the methyltransferase enzyme gene in susceptible and resistant cultivars, in order to identify alterations in gene expression that may be associated to higher levels of resistance. The experiment was conducted under greenhouse conditions. Four contrasting wheat cultivars were evaluated for resistance to preharvest germination. Planting was carried out in pots, in a randomized complete block design with three replications. In the physiological maturation stage (Z90), the harvests were harvested for phenotyping, using two methodologies: BRASIL (2009) and Nörnberg (2015), the collection of spikes was also performed for molecular analyzes. RNA extraction was performed according to the method described by Zeng and Yang (2002). Then, the RNA was treated with the enzyme DNAse, where cDNA synthesis was performed for use in semi-quantitative PCR analysis. The target gene of the enzyme Methyltransferase, and the Tubulin gene as a reference, were analyzed. The magnitude of expression of each gene was evaluated by means of densitometry of the amplified bands. The results show the importance of the joint execution of the phenotyping method for an efficiency during the classification process of new cultivars with germination resistant genes in the pre-harvest, and the analysis of genetic expression suggests that the maintenance of the methylated DNA can be a factor that contributes to the resistance to germination in the pre-harvest in wheat, because the resistant cultivars present greater accumulation of transcripts of the gene encoding methyltranferase.