Submitted to: Soybean Research World Conference Proceedings
Publication Type: Proceedings
Publication Acceptance Date: January 10, 2003
Publication Date: February 5, 2004
Citation: Ray, J.D., Fritschi, F.B. 2004. Real time pcr analysis of selected genes expressed in leaf tissue during soil drying [abstract]. VII World Soybean Research Conference. p. 178. Technical Abstract: Most plant physiological processes respond similarly to soil drying. Essentially, no response is evident until 60-70% of the available soil water has been lost. Critical physiological processes such as transpiration, photosynthesis, and leaf expansion have been shown to respond in this manner over a wide range of species. However, few studies have followed individual gene expression as the soil dries over a range of available soil water contents. In this experiment we grew two soybean genotypes ('Williams 82' and 'Maple Arrow') in a controlled environment growth chamber and imposed a slow soil-drying regime. As the soil dried, transpiration was measured in relation to well-watered control plants. As transpiration changed from 100% of control to 0% over the length of the experiment, leaves from individual plants were harvested approximately every 10% drop in transpiration. At the end of the experiment, daily transpiration was related to the available soil water content measured as the fraction of transpirable soil water (FTSW). RNA was extracted from the harvested leaves. The expression of selected genes over the course of the dry down was analyzed using Real-Time PCR. Transcripts of two genes, actin and DREB1 were shown to be stable across the full range of soil water contents. These genes were used to normalize the response of other genes. Differences in expression in response to soil water content (FTSW) were clearly evident among the genes evaluated.