Caracterização fisiológica e molecular de plantas de arroz mutantes para o transportador de zinco OsZIP7

Abstract

Rice is one of the most important crops in the world, being daily food for about half of the world population. However, rice grain is poor in micronutrients such as Fe and Zn, the two most commonly deficient minerals in the human diet. In plants, both Fe and Zn must be absorbed from the soil, distributed and stored in the plant, so that their concentrations are maintained at sufficient but not toxic levels. The understanding of the mechanisms and proteins involved in the maintenance of Fe and Zn homeostasis in plants has the potential to benefit agriculture, improving the use of micronutrients by plants, as well as to indicate approaches that aim at biofortification of the grains, increasing their nutritional quality. Thus, this work aims to characterize the oszip7 mutant and the role of the OsZIP7 transporter in Zn transport in rice plants. The study was developed in the Laboratory of Plant Physiology of Agrobiological Interest of the Federal University of Santa Maria. Rice plants of the oszip7 mutant strain and the respective wild type (Nipponbare cv.) Were grown in a greenhouse under a hydroponic system and submitted to a nutrient solution: control solution, Zn excess, Zn deficiency and deficiency Fe. After 24 days of cultivation, shoot growth, root system growth and structure, root and shoot dry matter, chlorophyll fluorescence, chlorophyll a / b caratenods concentration, SOD and POD enzyme activity were evaluated. concentrations of H2O2, expression of the OsZIP7 gene by RT-qPCR and quantification of elements such as Fe and Zn by ICP-OES. Plants of the oszip7 mutant when cultivated in Zn deficiency showed an increase in leaf area growth, root length, root diameters and surface area, when analyzed for elemental concentration in the tissues of shoot plants of the mutant showed a reduction in the concentrations of Zn, when compared to the wild type. Expression of the OsZIP7 gene in wild-type plants was enhanced when subjected to Zn deficiency. When the plants were subjected to excess Zn, the expression of the OsZIP7 gene was suppressed in comparison with the wild type.