Functional studies of Tectona grandis genes involved in the formation of wood and tolerance to environmental variation

• Autor(a) principal: Oliveira, Perla Novais de
• Data de Publicação: 2021
• Tipo de documento: Tese
• Idioma: eng
• Título da fonte: Biblioteca Digital de Teses e Dissertações da USP
• Texto Completo: https://www.teses.usp.br/teses/disponiveis/11/11144/tde-17022021-164313/
• topic: Crescimento secundário; Drought stress; Estresse hídrico; Estresse salino; Formação de madeira; Salinity stress; Secondary growth; Teak; Teca; Wood formation

Teak (Tectona grandis L.) is one of the most valued wood in the world and, despite the expansion of plantations of this species in the last 15 years, little is known about its molecular dynamics regarding both its wood, and their tolerance for environmental variations. New genetic engineering procedures, including functional characterization of genes, appear as alternatives to initiate such studies. The transcriptome that was sequenced and analyzed at the Laboratory of Genomics and Molecular Biology, ESALQ/USP, showed the presence of genes (some of them as transcription factors) related to response to stress and wood growth. The evaluation of function of these transcribed genes and their molecular interactions, allows a better understanding of how these phenomena occur in the species, enhancing the potential of using them in genetic improvement. In this work, functional studies were conducted to characterize the three selected genes, TgMYB2, TgERF1 and TgTPS1. The TgMYB2 was successfully isolated from T. grandis constitutively in tobacco plants in order to investigate its role in the regulation of secondary wall formation. Also, the characterization of TgMYB2 TgMYB2 by heterologous expression, has been shown and provided evidences for its important role in regulating cellulose, hemicellulose and lignin biosynthesis pathways. In addition, it was characterized the novel abiotics stress-responsive TgERF1 gene, an AP2/ERF type transcription factor. Overexpression of TgERF1 in tobacco enhanced tolerance to salt and drought stresses, altering physio-biochemical parameters, and activation of an array of stress-responsive genes at molecular level. Given the importance of trehalose and the TPS family in the response to stress, a novel class II TPS protein from T. grandis was isolated and characterized The phenotype of TgTPS1-overexpressing tobacco plants was similar to the WT under control conditions, but the transgenic plants showed improved tolerance to salt and drought stress. Thus, these results provide relevant insights to unravel the mechanisms of wood formation and stress tolerance, potentially being useful for future studies aiming to improve productivity and tolerance for environmental variations using biotechnological approaches.