CONICET | Buscador de Institutos y Recursos Humanos

Plants are plastic organisms that optimize growth in response to a changing environment. This adaptive capability is regulated by several external cues, including light, which has a particularly prominent role. Of the diverse light sensing photoreceptors that plants possess, phytochrome photoreceptors are exquisitely tuned to detect spectral changes indicative of nearby vegetation. The phytochrome-activated surveillance system initiates compensatory changes in plant architecture and reproductive timing to suit more crowded conditions. In nature this so-called shade-avoidance-response (SAR), is critical for plant survival, but it is troublesome for farmers, as SAR can impact crop robustness and yield. Plants exhibiting SAR have distinctive, elongated leaves that typically have low biomass. These traits are evident in Arabidopsis phytochrome-deficient mutants, but almost nothing is known of how this pathway implements leaf architectural change throughout development. In this work, we utilize our wide-ranging genetic resources, time-resolved growth, microscopy and transcriptome analysis to provide evidence for a developmentally timed phytochrome regulation of leaf architecture.Overall, this work helps delineate the light-activated mechanisms that control leaf shape and biomass, key indicators of yield in crops.