α-Glucosidase I is required for cellulose biosynthesis and morphogenesis in Arabidopsis

摘要: Novel mutations in the RSW1 and KNOPF genes were identified a large-scale screen for that affect cell expansion early Arabidopsis embryos. Embryos from both types of mutants radially swollen with greatly reduced levels crystalline cellulose, principal structural component wall. Because was previously shown to encode catalytic subunit cellulose synthase, similar morphology knf rsw1-2 embryos suggests phenotype is largely due their deficiency. Map-based cloning KNF gene enzyme assays demonstrated encodes α-glucosidase I, catalyzes first step N-linked glycan processing. The strongly content indicates glycans are required biosynthesis. synthase subunits do not appear be N glycosylated, N-glycan requirement apparently resides other component(s) machinery. Remarkably, cellular processes than extracellular matrix biosynthesis formation protein storage vacuoles unaffected Thus cells, like yeast, trimming function only small subset N-glycoproteins.