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Abstract Detail


Growth and Vegetative Development

Nambeesan, Savithri [1], Srivastava, Alka [2], Datsenka, Tatsiana [2], Mattoo, Autar K. [3], Handa, Avtar K. [2].

Polyamine regulated gene expression in tomato (Solanum lycopersicum) fruit.

Polyamines (PA) have been implicated in a multitude of cellular and developmental functions in plants, but little is known about their mode of action. To elucidate the role of PAs in tomato fruit growth and development we developed and characterized tomato plants overexpressing SAMdc under a ripening regulated promoter (E8) resulting in accumulation of spermidine and spermine in fruits. Global profiling of transcripts using a custom made macroarray showed that about one quarter of genes were regulated by increased PAs in ripening fruits. Differentially up-regulated genes were twice as abundant as down-regulated genes in the high polyamine fruits. The differentially regulated genes represented a wide range of functional categories including transcription, translation, signal transduction, chaperone function, stress response, amino acid biosynthesis, ethylene biosynthesis and action, polyamine biosynthesis, isoprenoid metabolism, and flavonoid biosynthesis. Collectively these results suggest a role of PAs as anabolic growth regulators. To determine if the observed changes were indeed due to polyamines and not due to modulation of SAM levels, we generated independent transgenic tomato lines over-expressing spermidine synthase (Spdsyn) under CaMV 35S and E8 promoters. Preliminary field evaluation of Spdsyn transgenics indicates altered fruit set and delayed fruit ripening with some 35S-Spdsyn transgenic plants exhibiting abnormal vegetative growth. Transcript profiling of ripe fruit from E8 and CaMV 35S yeast Spdsyn expressing transgenic plants is in progress. These results will be compared with SAMdc transgenic fruits to determine if transcriptional effects seen in SAMdc transgenic fruits are due to PA accumulation.


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1 - Purdue University, Department of Horticulture and Landscape Architecture, 625 Agriculture Mall Drive, West Lafayette, IN, 47907, USA
2 - Purdue University, Department of Horticulture and Landscape Architecture
3 - USDA-ARS, Henry A. Wallace Beltsville Agricultural Research Center

Keywords:
tomato
polyamines
development
gene expression.

Presentation Type: Plant Biology Abstract
Session: P
Location: Exhibit Hall (Northeast, Southwest & Southeast)/Hilton
Date: Sunday, July 8th, 2007
Time: 8:00 AM
Number: P26047
Abstract ID:1519


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