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Title: STRAWBERRY FRUIT PROTEIN WITH A NOVEL POST-TRANSLATIONAL INDOLE-ACYL MODIFICATION.

Author
item Slovin, Janet
item PARK, SEIJIN - UNIVERSITY OF MINNESOTA
item COHEN, JERRY - UNIVERSITY OF MINNESOTA

Submitted to: Horticultural International Congress Proceedings
Publication Type: Abstract Only
Publication Acceptance Date: 6/5/2006
Publication Date: 8/13/2006
Citation: Slovin, J.P., Park, S., Cohen, J. Strawberry fruit protein with a novel post-translational indole-acyl modification.. Horticultural International Congress Proceedings. p. 297

Interpretive Summary:

Technical Abstract: Although the importance of auxin in development and ripening of strawberry (Fragaria) fruit is well established, little is known about auxin metabolism in strawberry, or auxin functions in these important agricultural processes. Auxin is found in both free and conjugated forms. We found that achenes and receptacles of Fragaria vesca cultivar Yellow Wonder contained conjugated indole-3-acetic acid (IAA) that was insoluble in organic solvents and yielded IAA after strong alkaline hydrolysis, suggesting that IAA was attached to proteins. Protein bound IAA appears to account for a significant fraction of the IAA in the fruit tissues. To investigate the strawberry IAA protein conjugate class further, a polyclonal antibody was produced to IAA-glycine attached to BSA. This antibody detects neutral indolic esters, monocarboxylic-amino acid IAA conjugates and IAA-proteins. Both achenes and receptacles of strawberry showed an immuno-detectable band at 76 kDa. 2-D polyacrylamide gel electrophoresis resulted in a broad cross-reactive spot, which was analyzed by LC-MS/MS following in-gel trypsin digestion. The strawberry IAA-protein was tentatively identified by peptide fragment analysis as either a chaperonin related to the hsp60 class of proteins or, alternatively, an ATP-synthase. We are developing a reference system for testing gene function in the Rosaceae using the diploid strawberry, F. vesca because it has a small genome (slightly larger than Arabidopsis), is a small plant with a short seed to seed cycle, shows good fecundity and is self-fertile, has a fairly well populated genetic map, and is transformable by Agrobacterium. The inbred line 5AF7 will be used to test the possibility that proteins with functions related to stress responses (hsp60) or energy metabolism might be modified by IAA as part of the process of fruit development.