Professor Gerhard Leubner

Research interests

Seed biology - Cross-species approaches to germination, dormancy and quality of plant seeds

Plant seeds and fruits are at the beginning and the end of all important food supply chains that are central to human existence (food security and sustainability). They are the major means of propagation of important food and feed crops, and their harvest yield and quality determine nutritive value, consumer health and well-being, and beyond (e.g. biofuel crops). Plant seed and fruit germination is the most important adaptive early life-history trait and is timed by dormancy to avoid germination at unfavourable weather conditions for subsequent plant establishment and reproductive growth. Adaptation of germination to abiotic stresses and changing environmental conditions is decisive for fitness and survival of a species. Two opposing forces provide the basic physiological mechanism for the control of seed germination timing and synchrony: The increase in the growth potential of the embryo leading to cell-wall extension growth, and the restraint weakening of the various seed covering layers like endosperm, testa (seed coat), pericarp (fruit coat), as well as artificial envelopes applied by seed technologists.

We ('The Seed Biology Place' - www.seedbiology.eu) use comparative approaches with model, weed and crop species representing diverse phylogenetic clades and distinct seed types for the identification of evolutionary conserved and species-specific mechanisms that control seed dormancy and germination. Molecular mechanisms that are underlying these processes are regulated by plant hormones. Gibberellins (GA), abscisic acid (ABA), ethylene, and jasmonate signaling and metabolism mediate environmental cues and in turn influence developmental processes like seed germination. To quantify responses to environmental cues and abiotic stresses (especially related to temperature and water availibility) we combine population-based threshold modelling, novel biomechanics and engineering techniques, tissue-specific hormone, transcriptome, qRT-PCR, next-generation sequencing, reverse-genetics and mutant analyses to enhance the understanding of seed tissue interactions by an integrated cross-species systems biology approach.

Our research is summarized in reviews and publications available on our website (www.seedbiology.eu), e.g. Linkies and Leubner-Metzger (2012), Weitbrecht et al. (2011), and Finch-Savage and Leubner-Metzger (2006). Seeds are the preferred germplasm that can be conserved and maintained for hundreds of years, and, thus, are central to the conservation of biodiversity of crops and wild species as genetic resources for future crop breeding programs also related to climate change. 'The Millennium Seed Bank Project' (www.kew.org) is the largest ex situ plant conservation project in the world (collaboration), and seed storage at seed companies is an important field for applied research, e.g. our collaboration project on sugarbeet seed technology with KWS (www.kws.de). The ERA-CAPS Consortium SeedAdapt has 'dimorphic fruits, seeds and seedlings as adaptation mechanisms to abiotic stress in unpredictable environments' as its research focus. 

Our long term goal is to understand the molecular basis underlying seed dormancy, longevity and germination to be able to improve 
seed quality and seedling performance (vigor, timing, uniformity and environmental control of germination) of horticultural and agricultural crops, and to contribute to improved weed management strategies in a changing climate. This research focus is central to the RHUL Research Theme "Security and Sustainability".

 

 

For further information: 'The Seed Biology Place' - www.seedbiology.eu

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