The retention of chlorophyll has affected the production of soy beans in Brazil, mainly in the cerrado biome. As a result, there has been a reduction in the quality of the lots, evidenced by a decline in germination and vigor, with losses in the establishment of appropriate plant population at planting time. Besides affecting the physiological quality of seeds, the presence of chlorophyll also has negative effects on the quality of extracted oil. The chlorophyll degradation occurs naturally at the final stages of seed development. However this degradation is affected by maturity, by drying conditions, application of chemical desiccants and climatic conditions, especially during periods of reserve accumulation and seed maturation. Despite the importance of the disappearance of chlorophyll in the seeds, knowledge about the mechanism of the pigment degradation is scarce. Thus, the objective of this study is to evaluate the influence of environment (high temperature and drought stress) in the expression of genes related to chlorophyll degradation and retention in mature soybean seeds. The research project will be conducted at the Experimental Farm Lageado FCA / UNESP - Botucatu, SP, and executed in three steps. In the first stage the seeds will be produced under conditions of water and temperature stress. Harvested seed will be characterized as the water content, the retention rate of chlorophyll, the chlorophyll content and the quality assessed by physiological tests of germination and vigor. In the second stage will take place molecular analysis, with RNA extraction from seeds, construction of cDNA and hybridization in soybean microarrays (Affymetrix), performed by the Molecular Core (UNIFESP). In the third step, microarray analysis will be done with the selection of key genes involved in chlorophyll retention, followed by validation of these genes by PCR in real time. The data will be subjected to analysis of variance. The averages obtained in the morphophysiological analysis will be compared to a same cultivar and between cultivars, by Tukey Test at 5% probability.
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