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Title: PARTIAL CHARACTERIZATION OF MAJOR AMIDE-LINKED CONJUGATES OF IAA IN ARABIDOPSIS SEED

Author
item PARK, SEIJIN - UNIVERSITY OF MINNESOTA
item WALZ, ALEXANDER - UNIVERSITY OF MINNESOTA
item MOMONOKIE, YOSHIE - TOKYO UNIV OF AGRICULTURE
item Slovin, Janet
item LUDWIG-MUELLER, JUTTA - TECHNISCHE UNIV DRESDEN
item COHEN, JERRY - UNIVERSITY OF MINNESOTA

Submitted to: American Society of Plant Biologists Annual Meeting
Publication Type: Abstract Only
Publication Acceptance Date: 7/1/2002
Publication Date: N/A
Citation: N/A

Interpretive Summary:

Technical Abstract: Previous studies of IAA levels in Arabidopsis identified free as well as several conjugated forms, including IAA-glucose and IAA-aspartate. However, the identified conjugates accounted, quantitatively, for only a minor fraction of the total IAA released by hydrolysis. In order to account for the unidentified IAA conjugate fraction, the indole-3-acetic acid (IAA) pools in Arabidopsis seeds were studied. We found that free IAA and ester-linked conjugates constituted less than 1 percent and 4 percent of the IAA pool. Higher molecular weight ester-linked conjugates were not detected. The 70 percent 2-propanol extractable amide-linked conjugates and solvent insoluble amide-linked conjugates accounted respectively for 17 percent and 78 percent of the total IAA in the seed. Total buffer soluble proteins in Arabidopsis seed were immunoblotted using an antibody raised to the 3.6 kDa IAA-peptide from bean. The major immunoreactive Arabidopsis protein at 35 kDa was identified and shown by GC-MS analysis to contain IAA in amide linkage. Immunohistochemical studies suggest that the 35 kDa Arabidopsis protein is localized in epidermal cells of the cotyledons.