Plants exhibit a remarkable ability to modify their growth and development in response to environmental signals. This ability is particularly striking during root development where plants have to forage in highly heterogeneous environments. I will describe how plant hormones enable roots to sense and/or respond to environmental signals. Examples include discovering how plants sense availability of moisture in soil by linking intercellular water fluxes with movement of hormones like auxin and ABA, triggering changes in root branching designed to maximise capture of soil resources. Plant roots also employ volatile signals like ethylene to sense changes in soil physical properties like compaction stress using a novel gas diffusion based mechanism. I will conclude by describing how mechanistic insights about hormone-regulated root plasticity is helping in the design of stress tolerant crops.
About Prof. Bennett:
The hidden half
of plant biology has been an enduring interest throughout Malcolm’s research career. He has characterised many of the regulatory signals, genes and mechanisms that control root growth, development and adaptations to their soil environment. Highlights include identifying the first transport protein described in plants for the hormone auxin termed AUX1 which controls root angle (Bennett et al, 1996, Science); and elucidating how roots preferentially grow towards or branch towards water availability using hydrotropism (Dietrich et al, 2017, Nature Plants) and hydropatterning responses (Orosa-Puente et al, 2018, Science). To uncover new traits determining water and nutrient use efficiency in crops, Malcolm and colleagues in Biosciences, Maths, Engineering and Computer Sciences have pioneered efforts to non-invasively image roots in soil. They have created the Hounsfield Facility (https://www.nottingham.ac.uk/microct/
), an unique X-ray based root imaging platform integrating robotics, microCT scanners (see image) and image analysis software. Research highlights include imaging novel root adaptive responses in soil termed Xerobranching and Hydropatterning, where roots only branch when in contact with water (Orman et al, 2018, Current Biology; Bao et al, 2014, PNAS) and discovering the ethylene based signalling mechanism underpinning root compaction responses (Pandey et al, 2021, Science). Malcolm has published over 200 research papers and review articles about root growth and development and is ranked in the top 1% most highly cited animal and plant biologists. His research activities have attracted several awards including a Royal Society Wolfson Research Fellowship (2013) and election as a member of the European Molecular Biology Organisation (EMBO; 2014) and Fellow of the Royal Society (2020).