title: Involvement of extracellular Cu/Zn superoxide dismutase in cotton fiber primary and secondary cell wall biosynthesis.
abstract: Extracellular Cu/Zn superoxide dismutases (CSDs) that catalyze the conversion of superoxide to hydrogen peroxide have been suggested to be involved in lignification of secondary walls in spinach, pine and aspen. In cotton fibers, hydrogen peroxide was proposed to be involved in the induction of secondary cell wall biosynthesis. Recently, we identified extracellular CSDs from developing cotton fibers using both immunological and epitope tagging techniques. Since cotton fibers are not lignified, we suggested that extracellular CSDs may be involved in plant cell wall growth and development processes other than lignification. In this addendum, we have further characterized the extracellular CSD in cotton fiber. Immunoblots, enzyme activity assays, and transcript levels show that an extracellular CSD is present in elongating primary walls as well as thickening secondary walls of cotton fibers. Our working model proposes that extracellular hydrogen peroxide levels, regulated by redox status-related enzymes including extracellular CSDs and peroxidases, may affect the processes of wall loosening and wall tightening.
authors.affiliation: University of New Orleans; New Orleans, Louisiana USA.
authors.forename: Hee Jin
authors.initials: HJ
authors.lastname: Kim
authors.forename: Barbara
authors.initials: B
authors.lastname: Triplett
references.citation: Eur J Biochem. 1999 Mar;260(3):726-35
references.pmid: 10103001
references.citation: Planta. 2008 Jul;228(2):281-92
references.pmid: 18425534
references.citation: PLoS Genet. 2008 Feb;4(2):e25
references.pmid: 18248099
references.citation: Planta. 2001 Jun;213(2):272-9
references.pmid: 11469593
references.citation: Proc Natl Acad Sci U S A. 2002 Aug 20;99(17):11109-14
references.pmid: 12154226
references.citation: Plant Physiol. 2001 Dec;127(4):1361-6
references.pmid: 11743074
references.citation: Plant Physiol. 1999 Mar;119(3):849-58
references.pmid: 10069824
references.citation: Plant J. 1994 Feb;5(2):157-72
references.pmid: 8148875
references.citation: FEBS Lett. 2002 Oct 9;529(2-3):198-202
references.pmid: 12372600
references.citation: Trends Plant Sci. 2004 Oct;9(10):490-8
references.pmid: 15465684
references.citation: Phytochemistry. 2000 Mar;53(5):565-70
references.pmid: 10724181
references.citation: Plant J. 2007 Jan;49(1):135-48
references.pmid: 17233796
references.citation: New Phytol. 2007;175(3):462-471
references.pmid: 17635221
references.citation: Methods Enzymol. 1984;105:93-104
references.pmid: 6328209
references.citation: Plant Physiol. 2001 Aug;126(4):1668-77
references.pmid: 11500564