Osmotic stress on genetically transformed tobacco plant seeds

Michele Trombin-Souza,Elisa Serra Negra Vieira,Camila Ribeiro De Souza Grzybowski,Yohana De Oliveira-Cauduro,Maristela Panobianco

doi:10.1590/2317-1545v39n4181134

Michele Trombin-Souza, Elisa Serra Negra Vieira + Show 3 more

Open Access

https://doi.org/10.1590/2317-1545v39n4181134

Copy DOI

Abstract

Abstract: Salinity and water deficit limit the productivity of several crops; thus, studies related to the genetic transformation of seeds in a model plant, such as tobacco, can be an alternative to minimize negative impacts caused by environmental conditions. The purpose of this work was to evaluate the tolerance to osmotic stress of seeds from genetically transformed tobacco plants, with the introduction of the proline-synthesizer gene (p5csf129a), under salinity and water deficit conditions. To do so, five events with differences in proline content were selected, ranging from 0.70 to 10.47 µmoles.g-1 of fresh mass. The used saline concentrations were: zero (distilled water); 50; 100; 150 and 200 mmol.L-1 of NaCl, whereas for the water deficit, simulated with PEG 6000, the following osmotic potentials were used: zero (distilled water); -0.2; -0.4; -0.6 and -0.8 MPa. Each tested treatment was evaluated through germination, first germination count and germination speed index tests. It is possible to conclude that seeds from genetically transformed tobacco plants with overexpression of the gene p5csf129a, a proline synthesizer, are more tolerant to osmotic stresses. Tabacco seeds with a proline content of 10.47 µmol.g-1 showed a better perfomance, revealing higher physiological potential.

Highlights

Genetic seed transformation with the introduction of low molecular mass osmolytes, such as the amino acid L-proline, may be a promising alternative to increase seedling capacity to tolerate osmotic stresses in the establishment of the stand
Proline synthesis in higher plants occurs via glutamate or via ornithine, and under conditions of osmotic stress, the highest biosynthetic rate is achieved via glutamate
Proline is synthesized from glutamic acid by Δ1-pyrroline-5-carboxylate (P5C), by two successive reductions catalyzed by the enzymes Δ’-pyrroline-5-carboxylate synthase (P5CS) and Δ’-pyrroline5-carboxylate reductase (P5CR) (Sekhar et al, 2007)

Summary

Introduction

Genetic seed transformation with the introduction of low molecular mass osmolytes, such as the amino acid L-proline, may be a promising alternative to increase seedling capacity to tolerate osmotic stresses in the establishment of the stand. Proline acts as an osmoprotectant in the osmotic adjustment and contributes to the stabilization of subcellular structures and Osmotic stress on tobacco seeds to the increase of osmolarity, providing the necessary turgidity for the expansion of cells under stress conditions (Taiz and Zeiger, 2009). Proline accumulation occurs normally in the cytoplasm, where this amino acid acts to stabilize subcellular structures (such as membranes and proteins), to eliminate free radicals, and to buffer the cellular redox potential under stress conditions (Posmyk et al, 2009). Proline is synthesized from glutamic acid by Δ1-pyrroline-5-carboxylate (P5C), by two successive reductions catalyzed by the enzymes Δ’-pyrroline-5-carboxylate synthase (P5CS) and Δ’-pyrroline5-carboxylate reductase (P5CR) (Sekhar et al, 2007)

Objectives

Methods

Results