Microarray analysis of gene expression patterns in Arabidopsis seedlings under trehalose, sucrose and sorbitol treatment

Trehalose is the non-reducing alpha-alpha-1, 1-linked glucose disaccharide. The biosynthesis precursor of trehalose, trehalose-6-phosphate (T6P), is essential for plant development, growth, carbon utilization and alters photosynthetic capacity but its mode of action is not understood. In the current research, 6 days old seedlings of Arabidopsis thaliana (Columbia ecotype) were grown in liquid culture containing 100 mM trehalose, sorbitol or sucrose for 24 hours. Changes in the genes expression patterns were studied by cDNA microarray analysis. In sucrose treatment expression of 1745 genes was significantly changed. But trehalose changed significantly the expression of only 162 genes compared to sorbitol after 24h treatment. Gene expressions profiles revealed that 100 mM trehalose altered 5% of the genes which are changed by 100 mM sucrose. Statistical analysis showed that only 4 genes which are induced by trehalose repressed by sucrose. Exogenous trehalose treatment did not down-regulate the expression of carbon catabolite genes, but up-regulates a specific combination of genes known from biotic stress responses. Trehalose induced gene expression responses related to ROS and secondary metabolism activation. The expression profile shows particularly up-regulation (8-fold) of a glutathione transferase (GST22) under trehalose but not sucrose. Also, trehalose treatment induced expression of the JA and ethylene signaling pathways factors. These findings revealed that trehalose or its precursor, T6P, are important in gene expression regulation of plants.