Submitted to: The Plant Genome
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 2/25/2009
Publication Date: 8/1/2009
Citation: Zhu, J., Patzoldt, W.L., Radwan, O., Tranel, P.J., Clough, S.J. 2009. Effects of Photosystem II Interfering Herbicides Atrazine and Bentazon on the Soybean Transcriptome. The Plant Genome. 2:191-205. Interpretive Summary: Molecular mechanisms behind plant disease resistance, and the genes controlling these mechanisms, are not fully understood. One developing theory is that the plant photosystem centers are involved in defensive measures. We applied photosystem II inhibiting herbicides atrazine and bentazon to soybean leaves and identified over 6000 genes that were affected within 8 hours of herbicide treatment. We observed the induction of many genes related to oxidative stress as well as genes related to defense and cell recovery. These data are important as they provide insight into the biology of plant response to photosystem II inhibition, and also provide material for comparison to gene expression studies involving pathogens.
Technical Abstract: Atrazine and bentazon are both photosystem II inhibiting herbicides that interfere with photosynthetic electron transport provoking oxidative stress. While atrazine is lethal to soybean, bentazon does not kill soybeans because of the capability of soybeans to metabolize the herbicide. Gene expression profiling was conducted using cDNA microarrays to understand the responses of soybeans to PSII interruption and concomitant oxidative stress caused by atrazine and bentazon by monitoring expression at 1, 2, 4, and 8 h after treatment (HAT). The microarray study revealed that 6,646 genes were differentially expressed with high statistical significance over the experiment with 88% of them sharing similar expression pattern between the atrazine and bentazon treatments. Many genes related to xenobiotic detoxification and antioxidation such as cytochrome P450s, glutathione-S-transferases, superoxide dismutases, catalases and tocopheral cyclases were induced by the herbicides. The study also discovered plants treated with bentazon started to recover between 4 HAT and 8 HAT as reflected in the decreased amplitude of fold changes of most genes from 4 to 8 HAT. The 12% of the genes that were differentially expressed between atrazine and bentazon were largely related to cell recovery, such as genes related to ribosomal components.