title: Formation of rhamnogalacturonan II-borate dimer in pectin determines cell wall thickness of pumpkin tissue.
abstract: Boron (B) deficiency results in inhibition of pumpkin (Cucurbia moschata Duchesne) growth that is accompanied by swelling of the cell walls. Monomeric rhamnogalacturonan II (mRG-II) accounted for 80% to 90% of the total RG-II in B-deficient walls, whereas the borate ester cross-linked RG-II dimer (dRG-II-B) accounted for more than 80% of the RG-II in control plants. The results of glycosyl residue and glycosyl linkage composition analyses of the RG-II from control and B-deficient plants were similar. Thus, B deficiency does not alter the primary structure of RG-II. The addition of (10)B-enriched boric acid to B-deficient plants resulted within 5 h in the conversion of mRG-II to dRG-II-(10)B. The wall thickness of the (10)B-treated plants and control plants was similar. The formation and possible functions of a borate ester cross-linked RG-II in the cell walls are discussed.
authors.affiliation: Forestry and Forest Products Research Institute, P.O. Box 16, Tsukuba Norin Kenkyu Danchinai, Ibaraki 305-8687, Japan. tishii@ffpri.affrc.go.jp
authors.forename: T
authors.initials: T
authors.lastname: Ishii
authors.forename: T
authors.initials: T
authors.lastname: Matsunaga
authors.forename: N
authors.initials: N
authors.lastname: Hayashi
mesh_terms: D001881:Borates / Q000737:chemistry / Q000378:metabolism; D001895:Boron / Q000737:chemistry / Q000378:metabolism / Q000502:physiology*; D002473:Cell Wall; D019662:Cucurbitaceae / Q000737:chemistry / Q000166:cytology / Q000254:growth & development* / Q000648:ultrastructure; D010368:Pectins / Q000737:chemistry / Q000378:metabolism*; D018515:Plant Leaves / Q000166:cytology / Q000254:growth & development / Q000378:metabolism; D011108:Polymers / Q000737:chemistry
chemical_list: D001881:Borates; D011108:Polymers; C042492:rhamnogalacturonan II; D010368:Pectins; D001895:Boron