Seed germination and seedling vigour of transgenic tobacco (Nicotiana tabacum L.) with increased proline accumulation under osmotic stress

ABSTRACT

Proline plays important roles in various stages and processes of plant development. However, there are few reports on the effect of endogenous proline accumulation on germination and seedling vigour under suitable conditions of germination and development. The aim of this work was to evaluate the effect of endogenous proline in transgenic tobacco (Nicotiana tabacum L.) constitutively expressing the VaP5CSF129A gene in germination and seedling vigour. Under optimal conditions of germination, the transgenic seeds had high proline content when compared to the non-transgenic plants. However, this higher accumulation did not result in better germination or seedling vigour, contrasting to reported results for exogenous proline application. The pre-treatment by water submersion indicated that the lowest initial seed germination with the highest proline concentration may be due to their greater post-harvest dormancy. When newly germinated seedlings were subjected to osmotic stress (−0.9 MPa), the free proline content increased proportionally in all genotypes and the transgenic events seedlings showed greater root length compared to those of the non-transformed control. This can be advantageous as, in theory, seedlings with longer roots may have a better chance of growing and exploring the different soil layers, allowing the transgenic events to be more tolerant to edaphic constraints.

KEYWORDS:

• Osmotic stress
• P5CS gene
• proline
• seed germination
• tobacco

Acknowledgments

We would like to thank UNOESTE for supporting this work.

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

FLA was recipient of a Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) scholarship. LGEV is a Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) research fellow.