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United States Department of Agriculture

Agricultural Research Service

Research Project: PHYSIOLOGICAL/BIOCHEMICAL MECHANISMS ASSOCIATED WITH GENETIC ALTERATION OF SOYBEAN QUALITY AND PRODUCTIVITY

Location: Soybean and Nitrogen Fixation Research

Title: Effects of temperature during soybean seed development on defense-related gene expression and fungal pathogen accumulation

Authors
item Upchurch, Robert
item Ramirez, Martha

Submitted to: Biotechnology Letters
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: July 28, 2011
Publication Date: August 11, 2011
Citation: Upchurch, R.G., Ramirez, M.E. 2011. Effects of temperature during soybean seed development on defense-related gene expression and fungal pathogen accumulation. Biotechnology Letters. 33:2397-2404. 2011.

Interpretive Summary: Soybean plants were exposed to three temperature regimens during seed development to determine the effect of temperature on the expression of eight soybean pathogen defense genes and the accumulation of two fungal pathogens in inoculated seeds. In soybean seeds analyzed before inoculation, either a day/night warm (34/26 degrees C) or a cool temperature (22/18 degrees C) relative to normal (26/22 degrees C) resulted in altered patterns of gene expression including substantially lower expression of genes PR1, PR3 and PR10. After seed inoculation with Cercospora kikuchii, pathogen accumulation was least in seeds produced at 22/18 degrees C in which of all defense genes, the protease gene MMP2 was uniquely most highly expressed. For seeds inoculated with Diaporthe phaseolorum, pathogen accumulation was least in seeds produced at 34/26 degrees C in which of all defense genes, PR10 was uniquely most highly expressed. Our seed assays clearly demonstrated that the temperature regimens we applied during seed development produced significant changes in seed defense-related gene expression both pre- and post inoculation and our findings support the hypothesis that global climate change, especially warming, may alter plant-pathogen interactions and thereby potentially crop productivity.

Technical Abstract: Soybean [Glycine max (L.) Merr] plants were exposed to three temperature regimens during seed development to investigate the effect of temperature on the expression of eight defense-related genes and the accumulation of two fungal pathogens in inoculated seeds. In seeds prior to inoculation, either a day/night warm (34/26 degrees C) or a cool temperature (22/18 degrees C) relative to normal (26/22 degrees C) resulted in altered patterns of gene expression including substantially lower expression of PR1, PR3 and PR10. After seed inoculation with Cercospora kikuchii, pathogen accumulation was lowest in seeds produced at 22/18 degrees C in which of all defense genes, MMP2 was uniquely most highly induced. For seeds inoculated with Diaporthe phaseolorum, pathogen accumulation was lowest in seeds produced at 34/26 degrees C in which of all defense genes, PR10 was uniquely most highly induced. Our detached seed assays clearly demonstrated that the temperature regimens we applied during seed development produced significant changes in seed defense-related gene expression both pre- and post inoculation and our findings support the hypothesis that global climate change may alter plant-pathogen interactions and thereby potentially crop productivity.

Last Modified: 7/25/2014
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