Cell Communication Determines Root Architecture
Root architecture is a trait that strongly contributes to the performance of plants. The way how plant root systems colonize the soil will be determinative for the all or not thriving growth of the above ground parts. Because plants are sessile organisms, the exploration of soil in search of water and nutrients is mainly dependent on steering and controlling cell division and elongation.
The presence of an endogenous tissue layer in which, on a regular basis, stem cells with high cell division competence are deposited represents a powerful instrument through which plants can easily generate new lateral root branches. These branches are not arbitrarily formed along a root axis, but their spacing is rather determined by an endogenous patterning mechanism that guarantees an even distribution of lateral organs over the entire length of the root. New insights in this patterning mechanism will be discussed with the emphasis on putative cellular and tissue communication systems that are involved.
The hidden half of plant biology has been an enduring interest throughout my research career. Over the last two decades I have led efforts to characterise key regulatory signals, genes and mechanisms that control root growth and development, such as discovering AUX1, the first auxin transport protein described in plants. Whilst my research initially employed molecular genetic approaches, over the last decade I have embraced a multidisciplinary systems biology approach, helping establish the BBSRC/EPSRC Centre for Plant Integrative Biology (CPIB) in 2007 and currently serve as its Director.
In the last 5 years I have led efforts at CPIB to non-invasively image roots in soil using X-ray based CT approaches. A BBSRC Professorial Research Fellowship (2010) and ERC Advanced Investigator (2012) awards have enabled me to build a multidisciplinary research team and Hounsfield CT Facility to achieve this goal. I have published >180 research papers and review articles about root growth and development and am ranked as one of the top 1% most highly cited animal and plant biologists. As a result of these research activities, I recently received a Royal Society Wolfson Research Merit Award (2013) and was elected a member of EMBO (2014).
Dr. Brady completed BSc and PhD degrees at the University of Toronto and was a Postdoctoral Fellow at Duke University. Her research focuses on understanding how a vast network of transcriptional interactions regulates root tissue development and function in Arabidopsis, tomato and sorghum. The Brady laboratory has identified a rich set of transcriptional patterns underlying the spatiotemporal development of roots, particularly xylem tissue. She is currently employing quantitative genetic, genomic, and systems biology approaches to further elucidate environmental signals are integrated with cell type development.
Prof. Draye uses a combination of experimental and modelling (FSPM) strategies, from the organ to the plant scales, to understand the dynamics of root system architecture and hydraulics. He interacts closely with soil hydrologists and molecular biologists to develop novel views of crop water use that integrate notions of growth, development, root hydraulic properties and soil water dynamics. Xavier is also active in the development of root image analysis tools and standards (RSML) and in the development of phenotyping systems. He is involved in the modelling section of the EMPHASIS infrastructure.
Plants have a remarkable capacity for regeneration by retaining a life-long ability to form new meristems. We are studying the early stages of de novo root meristem formation in the context of tomato stem-borne and Arabidopsis wound induced roots. My lab uses a combination of genetics, high resolution single-cell transcriptomics and bioinformatic analysis to follow development from the single-cells to entire organs.
Prof. Eissenstat works on ecological aspects of root systems, with an emphasis on woody plants. Some of the current areas of research include controls on root phenology, how roots of arbuscular and ectomycorrhizal trees forage for nutrient hotspots, factors influencing the lifespan of roots and root traits that can be used for scaling in Earth System Models.
The root endodermis - Walking the thin line between uptake and protection.
Nearly ten years ago we initiated a screen with the aim of identifying mutants with an impaired endodermal diffusion barrier in their roots. This SCHENGEN screen identified a receptor-like kinase SGN3 (also called GSO1), a non-transmembrane kinase (SGN1), the NADPH oxidase RBOHF (SGN4), as well as TPST (SGN2) an enzyme responsible for sulfating a number of peptide ligands, important for many aspects of plant development. Through cell-type specific complementation and bio-informatic searches, we identified two ligands as the TPST substrates responsible for the endodermal barrier defects of the mutants and demonstrated that they are ligands for the SGN3 receptor. We named the two ligands Casparian strip integrity factors (CIFs), because they are required for the integrity of Casparian strips, the ring-like cell wall impregnations that form the extracellular (apoplastic) diffusion barrier in the endodermis, analogous to animal tight/adherens junctions. Combining these latest findings with that of previous years, we now can conceive that all four SCHENGEN mutants identified in our screen constitute part of a signaling pathway that has evolved for surveillance of diffusion barrier integrity and assists the differentiating endodermis in formation of a continuous and tightly sealed Casparian strip network. The SCHENGEN pathway is unusual because it detects defects in subcellular structures by making use of the restricted subcellular localization of its signaling components. I will report on the logic of this intricate signaling network and our efforts to elucidate its precise molecular mechanism.
Her study focus on plant stress physiologist and mechanisms regulating grass tolerance to abiotic stress (heat, drought, salinity, and cold).
Prof. Javaux earned a Ph.D. in Soil Physics (2004) from the Université catholique de Louvain. He is author or coauthor of more than 75 peer-reviewed articles on solute transport in the vadose zone, surface connectivity and soil-plant interactions. His research combines experimental and modeling approaches to investigate solute transport and water flow in the soil-plant system, to improve our understanding of plant water relations and to develop upscaling methods to predict root water uptake and stress onset at large scales.
Hans Lambers’ key areas of research have been plant respiration, plant growth analysis, and plant mineral nutrition. He aims for integration of the fields of physiology and biochemistry at whole plant and vegetation levels. His group contributed significantly to our understanding of the mineral nutrition of Australian plants, especially Proteaceae, and crop legumes. In his work after his move to Australia, his team discovered why fertilisation with phosphorus readily leads to “phosphorus toxicity” in several Proteaceae. Apart from numerous primary papers and authoritative reviews, he also edited 12 books in his key research areas, and he trained many successful young researchers, at undergraduate level, as PhD students and as Postdoctoral Researchers. In 2006, Hans established the Kwongan Foundation for the conservation of Australia's biodiversity. With a team of scientists in WA, he uses this Foundation to secure UNESCO World Heritage Listing for Australia’s Southwest Biodiversity Hotspot. More at: https://www.facebook.com/kwonganfoundation/
Christophe Maurel has a long-standing interest in plant water transport. His group uses molecular and physiological approaches to investigate the modes of water transport regulation at the level of cloned aquaporins, purified membranes, living cells or organs like excised roots. Thus, the dynamics of aquaporins at the root cell surface and their constitutive cycling were found to be enhanced under salt and oxidative stresses, in relation to inhibition of root water transport. In addition, quantitative genetics, root phenotyping and mathematical modeling are combined to address the dynamics of growth and hydraulics in roots, showing how these adapt to environmental constraints. A molecular pathway that integrates oxygen and potassium levels to modulate root hydraulics and allows plants to survive flooding was recently uncovered.
Western agricultural systems are reliant on the application of inorganic nitrogen fertilisers that greatly enhance yield. However, production and application of nitrogen fertilisers account for a significant proportion of fossil fuel usage in food production and the major source of pollution from agriculture. Prof Giles Oldroyd studies the mechanisms by which some species of plants are capable of forming beneficial interactions with nitrogen-fixing bacteria, which provide a natural source of nitrogen for plant growth. A long-term aim of this research is to reduce agricultural reliance on nitrogen fertilisers and he currently heads an international programme funded by the Bill and Melinda Gates Foundation to explore the feasibility of engineering nitrogen-fixing cereals. He completed his PhD in 1998 at the University of California, Berkeley, studying plant/pathogen interactions and then moved to Stanford University, USA, to work on nitrogen fixation in the laboratory of Prof. Sharon Long. He has been an independent researcher at the John Innes Centre since 2002. He has been recognised by a number of awards for his research: EMBO young investigator; European Research Council young investigator; Society of Experimental Biology Presidents medal; Royal Society Wolfson Research Merit award and a BBSRC David Philips Fellowship.
Dr. Richardson's research focusses on the phosphorus nutrition of plants, with understanding of root physiological and morphological traits that contribute to the efficient uptake for P from soils. The importance of root-microbiome interactions and contribution of rhizosphere processes that mediate P availability in soil are also considered. The major objective of his research is to improve the efficiency by which P fertilizers are used in agricultural systems He is a current Group Leader for Integrated Agriculture Systems in CSIRO and holds an adjunct Professor position at University of Western Australia.
Adventitious roots are those that develop from non-root tissues. Their formation is a critical step in clonal propagation of elite plants. The trigger for adventitious root formation can be developmentally regulated or induced by wounding and other stress signals. Some important species for agriculture or forestry are very difficult to root, which limits their development and use. Our studies focus on the molecular mechanisms underlying adventitious root formation.
The establishment of plant-associated microbial communities with healthy plants, called the plant microbiota, defines a major research theme of my laboratory. Revealing molecular functions of these microbial assemblages for plant growth and health has priority in our work on the plant microbiota. This includes microbe-mediated nutrient mobilization from soil for plant growth and indirect pathogen protection through microbe-microbe interactions. We seek to understand how plants take advantage of the microbiota to adapt to adverse environments, which is key to identify molecular principles underlying plant-microbe ecology. Our long-term objective is to develop an integrated molecular concept that can explain how plants manage simultaneously pathogenic and beneficial microbes to ensure plant survival and maximize plant fitness. Much of our microbiology work involves the study of plant interactions with bacteria, fungi or oomycetes. We are pursuing an integrated approach that connects genetics, molecular biology, and biochemistry with computer science.
He received his Ph.D. from Lancaster University, UK (with Bill Davies), and after postdoctoral work at the University of Illinois-Urbana (with John Boyer) and the University of California-Davis (with Ted Hsiao and Wendy Silk), joined the University of Missouri in 1986. His research program emphasizes the physiology of plant adaptation to drought, with a primary focus on root growth maintenance. Studies have focused on model systems for precise imposition of water deficits in combination with kinematics of cell expansion patterns to investigate the complexity and coordination of processes involved in root growth regulation. Current projects include "scaling up" to address maize nodal root development under drought via an integrated “lab-to-the-field” team-based approach.
Using the Arabidopsis thaliana root meristem as a model system, aims to shed light on the molecular mechanisms that are involved in maintaining meristem activities and necessary to support continuous plant organ growth. In the root meristem of Arabidopsis thaliana stem cells in the apical region self-renew and produce daughter cells that differentiate in the distal meristem transition zone. To ensure root growth, the rate of cell differentiation at the transition zone must equal the rate of generation of new cells. By means of Wet Biology and Computational Modelling approaches we are interested in understanding how this balanced is achieved.
The main goal of my group is to understand how plants interact with other organisms. We plan to systematically identify and characterize genes, proteins and small molecular compounds that are important for the interactions, by using genomics, proteomics and metabolomics approaches. We aim to elucidate signaling network system for plant immunity by analyzing expression patterns of defense related genes and their post transcriptional regulation, such as protein modification. Molecules in organisms interacting with plants, such as microbes, nematodes, parasitic plants will be investigated to understand how these organisms overcome plant immunity system and manipulate the host. Pathogen infection of plants is economically damaging to agricultural industries worldwide. Understanding the molecular basis of how plants interact with others in nature will provide new strategies to combat pathogens. Website http://plantimmunity.riken.jp/index.html
Prof. Watt leads the Root Dynamics Group, which focuses on root and rhizosphere discoveries using advanced phenotyping technologies, for crop resource efficiencies. Her group combines field and controlled environment research with modelling to understand the structure and function of crop roots in soil, including interactions with soil microorganisms. She is the Executive Secretary of the International Society of Root Research and co-Chair of the International Plant Phenotyping Network Root phenotyping working group. Prior to joining Juelich in 2015, she was at CSIRO from 2001 in Australia, working on the improvement of wheat root systems for water use efficiency in rain fed conservation systems. She has collaborated on projects in Canada, Australia, India, USA and Europe. She received her PhD from the Australia National University in 2000. She got her BSc and MSc at Carleton University in Canada, working on root and rhizosphere discoveries in cereals and legumes with proteoid roots.