|Bae, Hanhong - USDA-ARS, BELTSVILLE, MD|
|Bae, Hyeun-Jong -|
Submitted to: Physiologia Plantarum
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: April 15, 2005
Publication Date: September 1, 2005
Citation: Bae, H., Herman, E.M., Bailey, B.A., Bae, H., Sicher Jr, R.C. 2005. Exogenous trehalose alters arabidopsis transcripts involved in cell wall modification, abiotic stress, nitrogren metabolism, and plant defense. Physiologia Plantarum. 125:117-126. Interpretive Summary: Trehalose is a novel sugar that is present in trace amounts in flowering plants. However, trehalose is abundant in yeast, fungi and stress resistant lower plants, such as the resurrection plant. Higher plants engineered to produce large quantities of trehalose survived severe drought and cold treatments and possessed above normal rates of photosynthesis. Evidence is mounting that trehalose altered plant growth and development by turning on and shutting off specific genes. The effects of trehalose on higher plant gene expression were screened in the present study using Arabidopsis, a well studied laboratory plant and genes on a chip technology representing 8,000 Arabidopsis genes. Results indicated that the expression of 90 Arabidopsis genes were altered at least two-fold by trehalose treatment. Among these were stress and plant defense related genes, as well as, genes involved in the construction and maintenance of the cell wall. Several Arabidopsis genes associated with nitrogen metabolism also were down regulated by trehalose treatment. Many of the genes altered by trehalose were also responsive to ethylene, a well known plant hormone. This research should benefit researchers interested in improving the stress tolerance of plants to cope with the widely anticipated effects of future environmental change.
Technical Abstract: Trehalose exists in most living organisms and functions as a storage carbohydrate and as an osmoprotectant in yeast, fungi and bacteria. Trace amount of endogenous trehalose have been detected in flowering plants and the trehalose biosynthetic pathway was essential for embryo maturation in Arabidopsis. Conversely, exogenous trehalose was toxic to higher plants and severely curtailed root and shoot growth. In the current study, 30 mM trehalose was added to two week-old liquid cultures containing Arabidopsis thaliana (Columbia ecotype) seedlings. Densely stained granular particles were detected in the extracellular spaces of cotyledons and roots of trehalose treated seedlings using transmission electron microscopy. Expression levels of 90 transcripts were altered by 1 to 6 h of trehalose treatment using DNA microarray analysis and 65 of these encoded either known proteins or putative proteins with known functions. The exogenous trehalose treatment altered transcript levels of transcription factors, cell wall modification, nitrogen metabolism, stress-related, defense-related and fatty acid biosynthesis genes. Many of the transcripts altered by trehalose treatment were associated with the ethylene and methyl jasmonate signaling pathways. The above findings were consistent with the suggestion that trehalose, or metabolites derived from trehalose, are important regulators of plant gene expression in higher plants.