One of the challenges that Europe has to address in the next decades is the use of renewable resources for energy and materials to decrease our dependence on petroleum-based products and foster a competitive low C economy. Plant fibers are important renewable resources, as they are cheaper and have a smaller C footprint compared to synthetic fibers. These features have greatly sensitized, in the last years, both the producers of composites/textiles and the consumers, on the need to find sustainable, non harmful alternatives to man-made fibers. Bast fibers in particular are used by both the textile and biocomposite sectors, however despite their economical importance, they have received less scientific attention than for instance cotton fibers. Several aspects linked to bast fiber growth and development are still obscure. CABERNET aims at filling this gap by proposing the following testable research hypothesis: some of the cell wall-related mechanisms regulating tip growth in cells like pollen tubes and seed trichomes can explain the development of bast fibers. To test this hypothesis the project formulates specific question related to different cell wall-related aspects of bast fiber development and their answers will be found in the 4 workpackages envisaged. The project proposes nettle as plant model, which produces fibers with remarkable properties, namely high tensile strength, fineness, silkiness, length and by doing so it aims at valorizing, on the long term, one of the most undervalued plants among the economically relevant ones. The approach used is multidisciplinary, indeed (high resolution) imaging, transcriptomics, biochemistry and functional analyses are proposed to address each of the scientific questions formulated in the project.