Prof. dr. R. (Ronald) Pierik

Plant-Environment Signaling
Associate Professor
Plant-Environment Signaling
+31 30 253 6838

Plant Photobiology: how to grow at high densities.

Ronald Pierik is head of the chair group Plant-Environment Signaling and professor of Plant Photobiology. Ronald is also chairing the Science Faculty EDI committee and member of the EDI steering group of Utrecht University. 

Ronald is interested in understanding the physiological and molecular photobiological processes that underpin shoot phenotypic plasticity at high plant densities. Plants display a suite of growth responses to nearby neighbours, called shade avoidance, which include enhanced shoot elongation and upward leaf movement in response to far-red light reflection by neighbours (see picture below (Fig1) for tobacco). These responses enable plants to avoid shading by neighbouring plants.

Fig1. Shade avoidance in cultivated tobacco


Alternatively, species from shaded forest understories (see e.g. picture below (Fig2) for a temperate rainforest undergrowth) canot outgrow the giant trees around them an have evolved ways to tolerate low light conditions, including the suppression of shade avoidance responses.



Fig2. Forest understory Vancouver Island, Canada.

My group studies regulatory pathways leading to shade avoidance responses, primarily in Arabidopsis. This work includes plant-plant interactions in Arabidopsis canopies, light signaling, plant volatiles, hormone interactions and gene expression patterns leading to regulation of cell growth. The schematic below (Fig3) depicts a simplified version of our current understanding of light-mediated nieghbor detection and signaling events. I have an additional interest in multiple stress resistance and work on projects studying crosstalk between competition and defense against pathogens and herbivores, as well as on signalling convergence between shade avoidance and submergence escape.

Fig3. Illustration of light-mediated signaling events in response to neighbor proximity. Image taken from Ballaré & Pierik 2017; Plant, Cell & Environment 40: 2530-2543.

Team members

Current PhD candidates and post-docs involved in shade avoidance and shade tolerance research in my group are found here. If you are interested in joining our team, get in touch with me and we can see if we can apply for funding with you.



This work is supported by various grants from the Netherlands Organisation for Scientific Research NWO-ALW (including VENI (2007-2010), VIDI (acquired in 2013), VICI (acquired in 2018), open competition (2007, 2014, 2018), Ecogenomics (2011-2014) grants), TTW OTP and Perspectief (2015, 2017, 2018), NWO Building Blocks of Life (2017), NWO Photosynthesis (2021). Utrecht University Focus and Mass investments, EMBO Long-term fellowships, CSC and Marie Curie grants.

Plant Photobiology
Inaugural lecture date