Poster: Vegetative development

Abs # 319: The role of a chloroplast chaperone in sucrose starvation.

Presenter:	Rizhsky, Ludmila , ludmilar@iastate.edu
Authors	Rizhsky, Ludmila  (A)   Bassham, Diane C (A)
Affiliations:	(A): Iowa State University

In plants, sugar is a key regulator of many metabolic processes and of signaling pathways. During decrease in photosynthesis or during leaf senescence, for example, plants can encounter sucrose starvation conditions. To study the mechanisms of plant responses to starvation, a comprehensive analysis of the molecular response of Arabidopsis suspension cells to sucrose starvation was performed. 343 transcripts showed elevated expression during sucrose starvation, belonging to different functional categories, including regulation of transcription, metabolism, cellular organization, and signal transduction. One of the up-regulated transcripts encodes a potential chloroplast chaperone. RNA blot analysis confirmed that the chaperone mRNA levels increased during sucrose starvation, both in suspension cells and seedlings. A GFP fusion with this protein is localized to chloroplasts when transiently expressed in protoplasts. A knockout mutant was identified in the chaperone gene, and growth of mutant seedlings arrested shortly after germination in the absence of sucrose, where as in the presence of sucrose, no phenotype was observed. Further analysis of the mutant phenotype will be presented.