Professor Gerhard Leubner

Research into plant seeds, fruits, and tubers for food supply chain security and sustainability
Publications
Academic Career
Supervised PhD and MSc students
Collaborator Network
Seed Milestones (1995-2012) and Research Interests
Selected Talks Presented at Conferences

• The Seed Science and Technology Group of Professor Gerhard Leubner, Royal Holloway University of London (RHUL), made important discoveries in the field of crop and weed seed germination, dormancy and quality using interdisciplinary and integrative approaches. Plant seeds, fruits and tubers are at the beginning and the end of almost all important food supply chains that are central to human existence (food security and sustainability).
• Plant propagules include seeds, fruits, tubers, buds and bulbs. Increasing their quality properties by breeding (molecular marker), innovative physiological enhancement technologies and beneficial microbes improves primary crop establishment and thereby increases the yield potential. Unlocking the untapped biodiversity to discover novel stress resilience and other quality trait genes, as well as developing innovative methods for breaking seed and bud dormancy to stimulate germination and sprouting, are key for adressing the global challenges.
• The team of Professor Gerhard Leubner has long-standing expertise in the field with relevance to collaborations with partners from industry (e.g. KWS, Syngenta, Tozer Seeds), organisations (e.g. Kew, RHS) and academia (e.g. Loughborough University gas plasma expert Dr Felipe Iza). This impactful research into industrial and global challenges is relevant to the plant food value supply chain (seed and seedling stress resilience, extreme weather events, global climate change). Developing environment-friendly sustainable seed technologies include non-thermal (cold) atmospheric gas plasma and other refinement technologies to improving crop seed quality.
• Hyperlink to our currently active research projects
  
  

• 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 including endosperm, testa (seed coat), pericarp (fruit coat), and artificial envelopes applied by seed technologists.
• Our long-term goal is to understand the mechanistic basis underlying seed dormancy, longevity and germination to be able to improve seed quality and seedling performance (vigour, timing, uniformity and environmental control of germination) of horticultural and agricultural crops, and to develop effective and environment-friendly weed management strategies to increase the resilience of food supply chains to the climate crisis.
• Hyperlink to our movie about the seed & biotechnology research at Royal Holloway University of London

• Improved crop seed quality and seedling performance achieved by breeding and innovative seed enhancement technologies is the cornerstone for maximum yield potential. Seed refinement technologies including priming, pelleting and the application of beneficial compounds lead to rapid germination, enhanced vigour and uniform seedling establishment even upon abiotic stress.
• Seeds are therefore the delivery systems of genetic and technological innovation for the sustainable intensification of agricultural systems and for managing environmental change. Improving crop seed quality trough refinement technologies is the topic of our REF Impact Case Study. Seed additives include fertilisers, crop protection chemicals, and biologicals such as plant hormones, allelochemicals and beneficial microbes
• High-quality crop seeds resilient to abiotic stresses is at the very core of the 'input plant value supply chain' and involves developing environment-friendly sustainable seed technologies, identifying molecular marker and novel assays enabling breeding of crop seed quality. The science, engineering and economics of agri-technologies converge at the seed.
• Hyperlink to a poster of the Seed Group about copllaboration and impact for vegetable industry and the horticulture sector.
  
  

• The team uses 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. We combine population-based threshold modelling, novel biomechanics and engineering techniques, advanced imaging methods (multispectral imaging (MSI), synchrotron-based radiation X-ray tomographic microscopy (SRXTM), SEM), tissue-specific hormone, transcriptome, RT-qPCR, next-generation RNA sequencing, reverse-genetics and mutant analyses to enhance the understanding of seed tissue interactions by an integrated cross-species systems biology approach.
• The ERA-CAPS Consortium SeedAdapt had 'dimorphic fruits, seeds and seedlings as adaptation mechanisms to abiotic stresses in unpredictable environments' as its research focus. 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 crop and wild species as genetic resources for future crop breeding programs also related to climate change. 'The Millennium Seed Bank Project' of Kew Royal Botanical Gardens (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.
• Our collaboration projects with I ndustry include sugarbeet seed technology with KWS Seed SE (www.kws.de), vegetable and herb seed quality with Tozer Seeds (www.tozerseeds.com), and developing novel weed seed and seedling management tools with Syngenta (www.syngenta.com). Our research contributed to the success of the Rocket Science Project of the Royal Horticultural Society (www.rhs.org.uk) and the UK Space Agency. Our Rocket Science publication (Chandler et al 2020) demonstrated that the spaceflight caused seed ageing and revealed molecular biomarker for seed quality.

• Novel technologies for improving seed, fruit, bulb and tuber quality.
• Improved uniformity and sturdiness of vegetable, flower and crop seedlings.
• Enhanced seed and seedling performance in stressful environments.
• Novel seed treatments to increase stress tolerance and resilience, e.g. heat or cold stress during leafy salad seedling raising.
• Reduction of post-harvest storage losses in quality and yield.
• Reliable material properties of vegetable and flower seed pellets.
• Reduced vegetable and flower seed and bud dormancy issues.
• New technologies and compounds to manage weed seed banks.
• Hyperlink to Impact article (2017) "Improving crop seed quality and seedling performance"

Since April 2012

Chair of Plant Biochemistry, School of Biological Sciences Royal Holloway, University of London, United Kingdom

Summary: Professor Gerhard Leubner is the Chair of Plant Biochemistry and Head of the Seed Science and Technology Group at Royal Holloway University of London. He has more than 25 years’ experience in seed research and is the curator of  'The Seed Biology Place' (www.seedbiology.eu) website. He was the lead PI of the ERA-CAPS Consortium SeedAdapt on dimorphic fruits, seeds and seedlings as bet-hedging adaptation mechanisms to abiotic stress and unpredictable environments. More applied projects are into weed ecophysiology and improving crop seed quality and seedling performance is crucial for plant/food value supply chain resilience to climate change. Improved crop seed quality and seedling performance achieved by breeding and innovative seed enhancement technologies is the cornerstone for maximum yield potential. Seed refinement technologies including priming, pelleting and the application of beneficial compounds lead to rapid germination, enhanced vigour and uniform seedling establishment even upon abiotic stress. Seeds are therefore the delivery systems of genetic and technological innovation for the sustainable intensification of agricultural systems and for managing environmental change. Collaboration projects with industry including into "Sugarbeet seed quality, production and technology" with KWS Seed SE and into the "Chemical manipulation and mechanisms of weed seed persistence" with Syngenta's Jealott’s Hill International Research Centre. The science, engineering and economics of agri-technologies converge at the seed.

Members of the Seed Science and Technology Group at Royal Holloway University of London: People

Seed molecular ecophysiology and biomechanics: Impactful research into germination, longevity, dormancy, dispersal and quality of plant seeds. Seed and fruit biomechanics and functional morphology (expertise of Dr Tina Steinbrecher). Plant seeds, fruits and tubers are at the beginning and the end of almost all important food supply chains that are central to human existence (food security and sustainability).

Weed seed molecular ecophysiology research: Research stream led by Dr Kazumi Nakabayashi. Novel weed managment tools for weed soil seed banks. Collaboration with Syngenta.
Crop seed technology and "gas plasma agriculture": Research stream led by Dr Tina Steinbrecher. Seeds as delivery systems for innovative crop enhancement technologies ("agri-tech"). High-quality crop seeds resilient to abiotic stresses is at the very core of the 'input plant value supply chain' and involves developing environment-friendly sustainable seed technologies including with gas plasma technology, identifying molecular marker and novel assays enabling breeding seed quality.
Sugar beet seed quality: Research stream led by Dr Jake Chandler. Molecular physiology into seed and seedling abiotic stress resilience trait biodiversity. Collaboration with KWS Seed SE.

Key words about our research interest: Environmental-friendly precision agri-technologies; Sustainable gas plasma crop seed treatments; Sustainable biochemistry and green biotechnology; Weed seed molecular ecophysiology; Unlocking the untapped biodiversity of novel abiotic stress resilience traits; Seed treatment with beneficial microbes; Mitigating extreme weather and climate change; Vertical farming.

Elected Trustee, Member of the ISSS Executive Commitee since 2011: International Society for Seed Science (ISSS)

Alfred Mayer Plenary Lecture "The germination of diaspores: origin, diversity and destiny of the seed habit" (2021): ISSS Awards and Honours
at the 13th Triennial Meeting of the International Society for Seed Science (ISSS) - Seed innovation systems for the 21st century. Online, United Kingdom 7-11 September 2021.
The invited Alfred Mayer Plenary Lecture is an overview lecture on seed biology will be presented by a well-recognized and respected seed researcher, chosen or approved by the ISSS Executive Committee.

2004-2012

Botany/Plant Physiology, Albert Ludwigs University, Freiburg i. Br., Germany
"Hochschuldozent" and independent group leader at the Institute for Biology II, Botany/Plant Physiology, Molecular Plant Sciences, Faculty Biology.
Since September 2010 "W3-Vertretungsprofessor" for Molecular Plant Physiology and Botany.
From Freiburg to London: During 2012 as a transition phase my group was working at two place, at Royal Holloway, University of London (RHUL) and University of Freiburg (F). Dr. Ada Linkies was leading the group in Freiburg.
Postdocs and PhD students in 2012: Dr. Ada Linkies, Dr. Annette Büttner-Mainik, Dr. Tina Steinbrecher, Kai Gräber, Karin Weitbrecht, Antje Vögele.
Main research areas: Our group has long research experience in basic and applied seed biology. The role of the seed covering layers for germination, water uptake, seed storage, after-ripening and dormancy release is an important research focus of our lab. We are interested in the molecular mechanisms of endosperm weakening and in the release of coat dormancy. The different covering layers are determinants of seed quality and exhibit the biodiversity of seed structures. We have expertise in various methods of seed and seedling technology, physiology, biochemistry and molecular biology. Our basic and applied seed research projects focus on environmental factors (light, temperature, water, abiotic stress) and on plant hormones as endogenous regulators (gibberellins, abscisic acid, ethylene, auxin, cytokinins, brassinosteroids). The utilization of plant hormones and inhibitors of their biosynthesis and action in seed treatment technologies affects seed germination and seedling emergence.
Basic research: Molecular mechanisms of endosperm weakening by hydrolases and/or reactive oxygen species (ROS). Grants by the "Deutsche Forschungsgemeinschaft", the ERA-NET Plant Genomics (vSEED) and the "Wissenschaftliche Gesellschaft Freiburg".
Applied research: Seed quality and seedling performance of ornamental and crop plant species. Collaborations with international seed companies. These projects are part of the Plant Biotechnology section of the ZAB (Zentrum für Angewandte Biowissenschaften).
Editorial Board Member: Seed Science Research, AoB Plants, Associate Editor Journal of Experimental Botany, Reviews Editor Planta
Elected Trustee, Member of the ISSS Executive Commitee since 2011: International Society for Seed Science (ISSS)

2000-2003

Botany/Plant Physiology, Albert Ludwigs University, Freiburg i. Br., Germany
Habilitand and independent groupleader at the Institute for Biology II, Botany/Plant Physiology.
Habilitation grant of the DFG (Deutsche Forschungsgemeinschaft). Project and "Habilitationsschrift: Molekulare Physiologie der Dormanz, Nachreifung und Keimung von Pflanzensamen".
Habilitation and "Privatdozent" since the end of 2003. Venia legendi in Botany/Plant Physiology.
Member of the organizing committee of the "Botanikertagung 2002 Freiburg i. Br.", especially responsible for the internet issues of the conference and the dynamic website for the conference organization.
"Baden-Württemberg Zertifikat hochschuldidaktischer Kompetenzen".

1993-2000

Friedrich Miescher Institute, Basel, Switzerland
With Prof. Dr. F. Meins (plant development).
I established an independent research project on the function and regulation of ß-1,3-glucanases and chitinases (PR-proteins) during plant development. Special focus on seed dormancy and germination of tobacco, tomato and pea. Regulation of PR gene expression and signal transduction by hormones and environmental factors.
Education in webdesign and internet technologies - Certificate WebPublisher SIZ® ("Schweizerisches Informatikzertifikat").

1991-1992

Cornell University, Ithaca, New York, USA
With Prof. Dr. O. C. Yoder (plant pathology).
Project on the molecular biology of the mating type genes of Cochliobolus heterostrophus, fungal pathogen of maize.
Postdoctoral fellowship granted by the DFG (Deutsche Forschungsgemeinschaft).

1986-1990

Doctoral work (Ph.D.)
Ruhr-University Bochum, Germany
Swiss Federal Institute of Technology (ETH) Zürich, Switzerland
With Prof. Dr. N. Amrhein (plant physiology & biochemistry).
Thesis "The role of hydroxycinnamoylputrescines in the tuberization process of potato plants".

1985-1986

Diploma work at the Ruhr-University Bochum, Germany.
With Prof. Dr. N. Amrhein (plant physiology & biochemistry).
Thesis "Phenylalanine-analogues as inhibitors of L-phenylalanine-tRNA synthetase".

1980-1986

Study of biology at the Ruhr-University Bochum, Germany.

Research
interests

• Plant physiology, development and allelopathy with a special focus on plant hormones and molecular biology of seeds and seedlings.
• All aspects of seed biology, in particular seed germination, seed dormancy, seed after-ripening, seed ecology, seed technology and seed quality.
• Biochemical and molecular mechanisms that control embryo growth, coat-enhanced dormancy and after-ripening.
• Seed evolution, especially with regard to the seed covering layers. Ecophysiology and evolutionary developmental biology (EVO-DEVO).
• Phylogeny-driven comparative seed biology projects with interdisciplinary methods and systems biology modeling.
• Molecular mechanisms of endosperm weakening: hydrolases, reactive oxygen species (ROS), hydrolases, and other cell-wall remodeling proteins.
• Pathogenesis-related (PR) proteins, especially ß-1,3-glucanase (ßGlu), chitinases, peroxidases, NADPH oxidases.
• Signal transduction pathways and gene regulation by plant hormones, temperature and light. Stress physiology and population-based threshold models.
• Seed biomechanics and systems biology, cross-species mathematical modelling of seed germination (vSEED).
• Seed storage, longevity and aging, basic and applied research in this area.
• Biotechnological properties of seeds and seedlings (seed quality, enhancements, technology, priming, coating, pelleting, resistance towards seed-associated pathogens).
• Our long term goal is to understand the molecular basis underlying seed dormancy and germination to be able to improve
  seed quality and seedling performance (vigor, timing, uniformity and environmental control of germination) of horticultural and agricuctural crops.
• Endosperm weakening: In members of the Solanaceae the endosperm appears to be a mechanical hindrance to seed germination. The endospermic hole of the germinated tobacco seed seems to be formed by "dissolution" rather than by "pushing" action. Class I ß-1,3-glucanase (ßGlu I) is induced just prior to endosperm rupture (after testa rupture) and is localized exclusively in the micropylar region of the endosperm where the radicle will penetrate. Transgenic seeds over-expressing ßGlu I in the seed covering layers directly demonstrate that ßGlu I promote radicle protrusion to facilitate germination by contributing to endosperm rupture of tobacco. After-ripening promotes testa rupture and releases coat dormancy. ßGlu I over-expression can replace the after-ripening effect on testa rupture, in reciprocal crosses only if the mother plant is an over-expresser.
• Testa and endosperm rupture are distinct events during the germination of Nicotiana spp. seeds (Cestroideae subgroup of Solanaceae) and of the Brassicaceae species Lepidium sativum and Arabidopsis thaliana (Müller et al. 2006, Linkies et al. 2009, Graeber et al. 2010, Morris et al. 2011). We have measured endosperm weakening of Lepidium sativum by using the puncture-force method and found it to be controlled by an ABA-GA and an ABA-ethylene antagonism (working model).
• Model species at different positions of the phylogenetic tree will help to unravel the evolution of the molecular mechanisms of endosperm weakening. Moving beyond Arabidopsis with cross-species work will make the Brassicaceae a model family. Brassicaceae family-wide qRT-PCR of seed germination and phylotranscriptomics require cross-species approaches (state-of-the-art cross-species qRT-PCR guideline: Graeber, Linkes, Wood, Leubner-Metzger 2011).
  
  

1995

Abscisic acid (ABA) delays endosperm rupture and inhibits the transcriptional induction of ßGlu I in the micropylar endosperm.

1998

Ethylene signalling pathways acting via EREBP-type transcription factors are involved in regulating ßGlu I induction and seed germination.

2000

Sense transformation reveals a novel role for ßGlu I in tobacco seed germination. 

2001

Brassinosteroids and gibberellins promote tobacco seed germination by distinct pathways

2003

2005

Water uptake and distribution in germinating tobacco seeds investigated in vivo by nuclear magnetic resonance imaging (MRI) and
Review: Plant hormone interactions during seed dormancy release and germination

Endosperm-limited Brassicaceae seed germination: Abscisic acid inhibits embryo-induced endosperm weakening of Lepidium sativum (cress) and endosperm rupture of cress and Arabidopsis thaliana and Tansley review: Seed dormancy and the control of germination