Proteome Responses to Desiccation in Magnolia ovata Seeds (project completed 2011)
Changes in legumin content in recalcitrant seeds of Magnolia ovata reflect their physiological status.
Seeds of Magnolia ovata (Magnoliaceae) become visible upon fruit dehiscence, showing the bright red aril that covers the seeds. Copyright: Anderson Cleiton Jose.
Magnolia ovata is indigenous to the riparian forest that is closely linked to the cerrado, an endangered biome with high biodiversity in Brazil under threat by human impact. Only a small fraction of the cerrado is protected in reserves; entire populations of species within the biome are destroyed at a high rate as a result of agriculture, mining and hydro-electric operations. Studies into seed behaviour of cerrado species contributes to the conservation of these species under threat. M. ovata is a common woody species of the riparian forest. Seeds of M. ovata are difficult to germinate for several reasons. Firstly, germination is extremely slow and takes ±2 months. This can partly be explained by a very small embryo; indeed, morphological dormancy has been described for other members of the Magnoliaceae family. In addition, the seed also has physiological dormancy that needs to be broken for successful germination. Lastly, severe drying kills the seed as it is sensitive to desiccation. A large fraction of all species in the riparian woody species has been classified as dormant or desiccation sensitive. The combination of both factors in M. ovata makes this species a good case study, although challenging. In order to better understand the behaviour of these difficult seeds gene expression was characterised in relation to desiccation and physiological dormancy, using 2D- protein electrophoresis patterns correlated with the physiological condition.
The objective of this project was to identify proteins involved in dormancy and seed desiccation. The purpose was to generate a better understanding of dormancy and seed desiccation of a species intolerant to full desiccation. The project may lead to the development of a diagnostics test to assess dormancy and desiccation tolerance in any accession of the MSB. The project aimed at developing a protocol to improve storage of recalcitrant species.
A correlation was found between the abundance of legumin isoforms and the desiccated state of these recalcitrant seeds. This could be explained either by differential expression of different members of this multi-gene family, or by post-translational modification.
Project partners and collaborators
Universidade Federal de Lavras
Key papers published since 2006:
José, A.C., da Silva, E.A.A., Davide, A.C. & Toorop, P.E. (2011) Protein expression upon desiccation and imbibition of Magnolia ovata seeds. Brazilian Archives of Biology and Technology 54: 465–476.
José, A.C., da Silva, E.A.A., Davide, A.C., Melo, A.J.S. & Toorop, P.E. (2011) Effects of drying rate and storage time on Magnolia ovata seed viability. Seed Science & Technology 39: 425–434.