Carbohydrate Metabolism in Wheat Leaves During Drought

Photosynthetic activity is greatly reduced in drought stressed leaves. This results to alterations in the carbohydrate metabolic equilibrium. Despite reduced carbon fixation, plants accumulate large amounts of water-soluble carbohydrates such as mannitol, glucose, fructose, and sucrose. These carbohydrates are used by plants as osmolytes to maintain leaf cell turgor, prevent protein denaturation and protect membrane integrity.

Scientists from the Australian Commonwealth Scientific Research Organization (CSIRO) monitored the regulation of carbohydrate metabolic genes in wheat during drought stress using cDNA microarray. Results revealed a reduction in the expression of most genes encoding for chloroplast enzyme involved in carbon fixation (Calvin cycle phase of photosynthesis). Transcript levels of the enzymes hexokinase and fructokinase, expressed in high levels in normal conditions, were also found to be significantly decreased. Conversely, expression of genes coding for enzymes necessary for glucose and fructan biosynthesis were upregulated.

The study may provide the foundation for future investigations on the elucidation of gene regulatory networks controlling carbohydrate metabolism.

The abstract of the paper published by Plant Molecular Biology is available at http://www.springerlink.com/content/w131275761277715/?p=86e70b79057d47e18ed5071d6e082837&pi=1