Magic™ Anti-Arabidopsis thaliana CESA1 (Phospho S162) polyclonal antibody

In silico search for the nucleotide sequences encoding cellulose synthases in the flax genome was carried out, together with the comparison of the identified sequences with the orthologous genes in dicotyledonous plants. The analysis resulted in the identification of 32 flax candidate genes, 16 of which encoded cellulose synthases with high possibility rate, while the remaining 16 encoded cellulose synthase-like proteins (Csl). The phylogenetic analysis of the protein products of the cellulose synthase genes allowed dividing them into six groups comprising cellulose synthases of different classes: CesA1/10, CesA3, CesA4, CesA5/6/2/9, CesA7, and CesA8. Paralogous sequences belonging to the classes CesA1/10 and CesA5/6/2/9, associated with the primary cell wall formation, were characterized by the higher intra-class similarity rate, than the orthologous sequences. At the same time, the genes that control cellulose biosynthesis for the secondary cell wall formation constituted distinct clades, CesA4, CesA7, and CesA8. The analysis of the 16 selected flax candidate cellulose synthase genes demonstrated that the flax genome contains at least 12 different variants of cellulose synthase genes, which belong to all six cellulose synthase clades. In such a way, at this stage, the cellulose synthase genes from all ten known CesA classes have been identified in the flax genome; however, their correct attribution to each of these classes requires some additional study.

Multiple cellulose synthase (CesA) subunits assemble into plasma membrane complexes responsible for cellulose production. In the Arabidopsis (Arabidopsis thaliana) model system, we identified a novel D604N missense mutation, designated anisotropy1 (any1), in the essential primary cell wall CesA1. Most previously identified CesA1 mutants show severe constitutive or conditional phenotypes such as embryo lethality or arrest of cellulose production but any1 plants are viable and produce seeds, thus permitting the study of CesA1 function. The dwarf mutants have reduced anisotropic growth of roots, aerial organs, and trichomes. Interestingly, cellulose microfibrils were disordered only in the epidermal cells of the any1 inflorescence stem, whereas they were transverse to the growth axis in other tissues of the stem and in all elongated cell types of roots and dark-grown hypocotyls. Overall cellulose content was not altered but both cell wall crystallinity and the velocity of cellulose synthase complexes were reduced in any1. We crossed any1 with the temperature-sensitive radial swelling1-1 (rsw1-1) CesA1 mutant and observed partial complementation of the any1 phenotype in the transheterozygotes at rsw1-1's permissive temperature (21 degrees C) and full complementation by any1 of the conditional rsw1-1 root swelling phenotype at the restrictive temperature (29 degrees C). In rsw1-1 homozygotes at restrictive temperature, a striking dissociation of cellulose synthase complexes from the plasma membrane was accompanied by greatly diminished motility of intracellular cellulose synthase-containing compartments. Neither phenomenon was observed in the any1 rsw1-1 transheterozygotes, suggesting that the proteins encoded by the any1 allele replace those encoded by rsw1-1 at restrictive temperature.