Carnivorous plants exploit animals as a nutritional source and have inspired long-standing questions about the origin and evolution of carnivory-related traits. To investigate the molecular bases of carnivory, we sequenced the genome of the heterophyllous pitcher plant Cephalotus follicularis, in which we succeeded in regulating the developmental switch between carnivorous and non-carnivorous leaves. Transcriptome comparison of the two leaf types and gene repertoire analysis identified genetic changes associated with prey attraction, capture, digestion and nutrient absorption. Analysis of digestive fluid proteins from C. follicularis and three other carnivorous plants with independent carnivorous origins revealed repeated co-options of stress-responsive protein lineages coupled with convergent amino acid substitutions to acquire digestive physiology. These results imply constraints on the available routes to evolve plant carnivory.

Genomes of the Venus Flytrap and Close Relatives Unveil the Roots of Plant CarnivoryHighlights d An early whole-genome duplication is the source of carnivory-associated genes d Trap-specific genes were recruited from the roots d Expansion of specific gene families enabled fine-tuning of hunting styles d Evolution of plant carnivory was paralleled by massive gene loss

ELONGATED HYPOCOTYL 5 (HY5), a member of the bZIP gene family, is a positive regulator of the light signaling pathway in Arabidopsis thaliana. Whereas the hy5 mutant exhibits an elongated hypocotyl when grown in the light, the hy5 homolog (hyh) mutant does not. Although the functions of HY5 and HYH in light-mediated seedling development have been revealed, the tissue-specific expression patterns of HY5 and HYH and their interconnected regulation are largely unknown. Here, we report that HY5 regulates HYH expression in roots and contributes to root growth under different light conditions. We generated HY5 and HYH transcriptional and translational fusion reporter lines to investigate their expression patterns. HY5 was constitutively expressed in all root tissues, while HYH was predominantly expressed in root xylem cells. Root growth after a dark-to-light transition was perturbed in the hy5 and hy5hyh mutant lines, but not in the hyh mutant line, indicating that HY5 plays a major role in light-regulated root growth. Light-induced HY5/HYH expression occurred autonomously in roots. HYH expression in roots was decreased in the hy5 mutant, suggesting that HY5 regulates HYH expression. Collectively, these results indicate that an organ-specific HY5-mediated pathway controls root photomorphogenic development independently of light signaling in the shoot.