Effects of Photosystem II Interfering Herbicides Atrazine and Bentazon on the Soybean Transcriptome 2. Glycine max

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. Keywords = stress Keywords = GST Keywords = ROS Keywords = D1 protein Keywords = Fuzzy k-means Keywords = plant Keywords: plant xenobiotic interaction Overall design: loop design, 12 direct comparisons, 2 technical repeats including dye swaps, 3 biological repeats