Characterization of the cell walls prepared from Populus alba cells grown in boron deficient medium
2006
Kakegawa, K.(Forestry and Forest Products Research Inst., Tsukuba, Ibaraki (Japan))
A new cell line of Populus alba L., designated T-0B, which was able to grow in a medium without boron, was established from previously reported T-5B cells maintained in a low-boron medium (5 microM). The boron content in T-0B cell walls was decreased to about one-third the level in the walls of the original Populus cells maintained in medium containing 100 microM boron. Rhamnogalacturonan II dimers, cross-linked by borate esters, were also decreased. A sugar composition analysis of the cell walls revealed decreases in arabinosyl and galacturonosyl residues, and an increase in glucosyl residues, compared with the levels in the original cell walls. Furthermore, the amounts of xylosyl, galactosyl, glucosyl and galacturonosyl residues in the extracellular polysaccharides increased significantly. These results suggest that the interactions among cell wall polysaccharides were weakened by decreases in the boronrhamnogalacturonan II cross-linkages resulting from boron deficiency. Consequently, cell wall polysaccharides, especially pectin, were released into the medium as extracellular polysaccharides.
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