Plant Fiber Team, UGSF, UMR CNRS 8576. University of Lille 1, France
Title:Organ-specific proteomics and targeted cell wall analyses in flax
Host: Edouard Pesquet
Flax (Linum usitatissimum L.) is a fiber plant species that has been used since antiquity for the fabrication of textiles (linen), as well as for the production of oil (linseed). Flax is also an excellent model to study cell wall biology as the inner- and outer-stem tissues of this plant contain cells with highly contrasted wall compositions. Cells from the inner xylem core have heavily lignified secondary cell walls containing up to 31 % lignin whereas the thick secondary cell walls of the long bast fibers present in outer stem tissues are richer in cellulose and contain only 4 % lignin. The use of an organ-specific proteomics approach allowed us to identify 1,242 non-redundant proteins present in 3 different fractions (soluble, membrane and cell wall) from 4 different flax organs (inner-/outer-stems, leaves and roots). Subsequent analyses of these proteins, as well as of other published flax proteomics data, enabled us to identify 405 proteins potentially involved in cell wall metabolism in this species. A study of potential protein networks using STRING (http://string-db.org
) underlined organ-/tissue-specific differences in protein networks potentially related to contrasted cell wall structure/metabolisms. Phylogenetic analyses of the flax cell wall proteins also allowed us to identify a marked paralogy in the XTH (Xyloglucan endotransglucosylase/hydrolase) IIIA family involved in cell wall remodeling events and potentially associated with the differentiation of flax bast fibers.