Fisiologia Vegetal
URI permanente para esta coleçãohttps://locus.ufv.br/handle/123456789/185
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Resultados da Pesquisa
Item Seed germination in response to salt stress and seed dormancy: On the roles of hormones and transcription factors(Universidade Federal de Viçosa, 2021-06-18) Silva, Nilo Cesar Queiroga; Ribeiro, Dimas Mendes; http://lattes.cnpq.br/8449292324218198The formation of a plant population depends on the plasticity of the germination of its seeds. This thesis aims to understand the mechanism of seed germination in response to salt stress and the role of transcription factors in germination. In chapter, it is reviewed the impact of climate change on seeds and the effect of hormonal balance in seeds. In addition, we present a brief review of the epigenetic effects on seeds and their impacts on plant adaptability, which can contribute to new perspectives. In the following chapters, we sought to investigate (i) the role of sodium and pH in hormonal balance during germination in Stylosanthes humilis. (ii) the role of transcription factors (TF) in dormancy and germination of Arabidopsis thaliana seeds. These studies were carried out in two independent experiments, which comprise chapters II and III presented here. In the second chapter, the following experiments were proceeded: seeds of S. humilis were incubated in a growth chamber. Ethylene, abscisic acid (ABA), 1-carboxylic acid-1-aminocyclopropane (ACC), ACC synthase (ACS) and ACC oxidase (ACO) and the primary metabolites were quantified. The results show that saline stress induces ABA synthesis independently of pH, leading to a reduction in the biosynthesis of ethylene, the main hormone involved in the germination of S. humilis. The third chapter aimed to understand how the transcription factor TEOSINTE BRANCHED1 CYCLOIDEA PROLIFERATING CELL FACTORS (TCP) family regulates the germination of Arabidopsis thaliana seeds. To help elucidate the functioning of the TCP8 and TCP14 genes, the TCP mutants were tested during seed germination. RNA- Sequencing data from seeds of TCP mutants were used to identify potential genes regulated by TCPs. The phenotype was evaluated and RT-qPCR (Real Time - quantitative PCR) were performed. In addition, transient gene expression analyses were performed on tobacco leaves. The results of this study show that TCP8 is a negative regulator of breaking dormancy in Arabidopsis thaliana. Together, these results suggest that TCP8 and TCP14 (both of class I TCPs) modulate the dormancy break in a contrasting manner. Thus, the role of TCP8 and TCP14 was demonstratedduring the germination of A. thaliana. Together, these data indicate the complexity of the germination process. Keywords: Germination. Dormancy. Seeds. Salt Stress. Stylosanthes humilis. Transcription factors. Arabidopsis thaliana.