Effect of chemical treatment on defense gene expression in Williams 82.

Expression analysis of soybean genes twenty-four hours after exposer to water (control), 1-methylcyclopropene (MCP), cobalt chloride 1mM (CC), or ethephon 4mM (ETH) in the moderately susceptible cultivar Williams 82. (A) Genes involved in ethylene biosynthesis and signaling, 1-aminocyclopropane-1-carboxylic acid synthase (ACS), 1-aminocyclopropane-1-carboxylic acid oxidase (ACO), and β-1,3-endoglucanase (PR2), (B) defense-related genes, pathogenesis-related protein 1 (PR1), Chitinase class I (PR3), Intercellular pathogenesis-related protein 10 (PR10), Chalcone synthase (CHS), basic peroxidase (Peroxidase), and ethylene response factor 1 (ERF1). Soybean seedlings were drenched with water (control), ethephon 4 mM, cobalt chloride 1 mM, or foliar sprayed with 1-MCP. Roots were sampled 24 hours after chemical treatment. The soybean actin gene was used as an internal control. The level of expression is shown relative to that of control plants. Each column represents the mean fold change of eight biological samples (four samples × two runs), and each sample consisted of a pool of two plants. Error bar indicates standard error of the mean (n = 8). Columns with different letters are significantly different (P<0.05).