Poster: Salinity

Abs # 108: Gene expression profile under salt stress in Arabidopsis pistils

Presenter:	Sun, Kelian , kelian@ufl.edu
Authors	Sun, Kelian  (A)   Hauser, Bernard A (A)
Affiliations:	(A): University of Florida

A number of environmental stresses promote ovule abortion. Microarray experiments using whole genome oligo arrays were performed to identify salt responsive genes in pistils. The transcript levels of ~22,000 genes were determined as a function of time stressed. Salt stress was done by transferring hydroponically grown plants to a growth medium supplemented with 200 mM NaCl. A total of 535 genes were identified as being salt responsive gene during the 24 hour experiment (P value ≤0.05). 404 genes were induced, while 131 gene were repressed more than 2.5 fold (the lower bound of the fold change is ≥2.5). The genes encoding proteins for sugar metabolism (two fructokinase), protein synthesis (L5 ribosomal protein) and DNA synthesis (PROLIFERA) were repressed, which was consistent with the decrease in the rate of cellular growth following stress. Since high salt interrupted the ion homeostasis of the plant, several transporters were induced to reestablish ion homeostasis, such as P-type ATPases and cation exchangers. ROS (reactive oxygen species) detoxification genes, including ascorbate peroxidase, peroxidase, superoxide dismutase, were down regulated late in ovule abortion, which is consistent with ROS initiation or causing ovule abortion. Following salt stress, the expression levels of about 22 signal transduction components and 59 transcriptional factors significantly changed. Binary hierarchical cluster analysis of the transcriptional factors showed waves of gene expression, which indicated that multiple regulatory pathways were activated. The common response elements were analyzed for each cluster of the transcriptional factors to identify genes under similar transcriptional control.