Research
Plants have developed advanced strategies to react and adapt to environmental changes, including competition with other organisms, sometimes even within their own species. Neighbor proximity in plants is perceived via a reduction of the red to far-red ratio (R:FR) in the light environment. As a result of low R:FR perception by phytochromes photoreceptors, plants trigger a set of molecular and physiological responses referred to as the "shade avoidance syndrome"; a process meant to outgrow neighboring vegetation. In addition to exhibiting strong growth responses, plants experiencing low R:FR display lower resistance capacities towards pathogens. This process is referred to as the shade-induced susceptibility, which is at the core of our research.
What governs the onset of the shade-induced susceptibility in plants?
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In the lab, we simulate the effect of plant-plant proximity by supplementing our white lighting with far-red LEDs, which triggers the shade avoidance syndrome (Fig. 1). This strong elongation response is accompanied by a reduction in plant defense capacities. Although the repression of plant defence by FR enrichment has been attributed to a direct interplay between growth and defence hormone signalling, other mechanisms also affected by FR, have not yet been considered.
We recently identified TARGET OF RAPAMYCIN (TOR) as a potential regulator of the growth-defense tradeoff in plants. TOR is a master growth regulator in eukaryotes that integrates the cellular energy and carbohydrate status to modulate downstream growth and defence responses. By coupling biochemistry, omics and physiology, we are currently investigating if and how low R:FR perception regulates TOR activity and signaling thereby promoting growth at the expense of defense in Arabidopsis. Given how conserved the TOR pathway is throughout the green lineage (and beyond), this work ultimately aims to unravel TOR-(in)dependent molecular pathways regulating the growth-defense tradeoff in plants, which could help develop more resilient crops.
