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Original Research ARTICLE Provisionally accepted The full-text will be published soon. Notify me

Front. Plant Sci. | doi: 10.3389/fpls.2019.01342

An integrative approach to analyze seed germination in Brassica napus.

 Marta Boter1, Julián Calleja-Cabrera1, Gerardo Carrera-Castaño1, Geoffrey Wagner2,  Sarah V. Hatzig2, Amine Abbadi3,  Rod J. Snowdon2,  Mónica Pernas Ochoa1* and  Luis Oñate-Sánchez1, 4*
  • 1Center for Plant Biotechnology and Genomics, National Institute of Agricultural and Food Research and Technology, Spain
  • 2Institute for Plant Production and Plant Breeding I, Faculty of Agricultural Sciences, Nutritional Sciences, and Environmental Management, University of Giessen, Germany
  • 3NPZ Innovation GmbH, Germany
  • 4Polytechnic University of Madrid, Spain

Seed germination is a complex trait determined by the interaction of hormonal, metabolic, genetic, and environmental components. Variability of this trait in crops has a big impact on seedling establishment and yield in the field. Classical studies of this trait in crops have focused mainly on the analyses of one level of regulation in the cascade of events leading to seed germination. We have carried out an integrative and extensive approach to deepen our understanding of seed germination in Brassica napus by generating transcriptomic, metabolic and hormonal data at different stages upon seed imbibition. Deep phenotyping of different seed germination associated traits in six winter-type B. napus accessions has revealed that seed germination kinetics, in particular seed germination speed, are major contributors to the variability of this trait. Metabolic profiling of these accessions has allowed us to describe a common pattern of metabolic change and to identify the levels of malate and aspartate metabolites as putative metabolic markers to estimate germination performance. Additionally, analysis of seed content of different hormones suggests that hormonal balance between ABA, GA and IAA at crucial time points during this process might underlie seed germination differences in these accessions. In this study, we have also defined the major transcriptome changes accompanying the germination process in B. napus. Furthermore, we have observed that earlier activation of key germination regulatory genes seems to generate the differences in germination speed observed between accessions in B. napus. Finally, we have found that protein-protein interactions between some of these key regulators are conserved in B. napus suggesting a shared regulatory network with other plants species. Altogether, our results provide a comprehensive and detailed picture of seed germination dynamics in oilseed rape. This new framework will be extremely valuable, not only to evaluate germination performance of B. napus accessions, but also to identify key targets for crop improvement in this important process.

Keywords: Germination, seed traits, Oilseed rape (Brassica napus), Metabolism, hormonal pathways, transcriptomic, Protein interaction, crop yield

Received: 12 Jun 2019; Accepted: 26 Sep 2019.

Copyright: © 2019 Boter, Calleja-Cabrera, Carrera-Castaño, Wagner, Hatzig, Abbadi, Snowdon, Pernas Ochoa and Oñate-Sánchez. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) and the copyright owner(s) are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.

* Correspondence:
Dr. Mónica Pernas Ochoa, Center for Plant Biotechnology and Genomics, National Institute of Agricultural and Food Research and Technology, Pozuelo de Alarcón, 28223, Madrid, Spain,
Dr. Luis Oñate-Sánchez, Polytechnic University of Madrid, Madrid, Spain,