Gene expression related to oxidative stress induced by herbicides in rice.

Herbicides are stressors that can have negative effects on plants. In Oryza sativa (L.), differential gene expression may be evalu-ated through real-time reverse transcription quantitative poly-merase chain reaction (RT-qPCR). The aim of this study was to evaluate the stability of candidate reference genes and to quan-tify the relative expression of oxidative stress genes at different times (12, 24, 48, and 96 hours after treatment [HAT]) with penoxsulam, cyhalofop-butyl, and bentazon herbicides. Norm-Finder, BestKeeper, and GeNorm software and the compara-tive ∆Ct method were used to assess expression stability and to determine the RT-qPCR threshold values of the candidate reference genes. The UBQ5 gene was the most stable among the reference genes analyzed. The gene expression results showed upregulation of OsCAT and OsMnSOD1 genes at all times after herbicide application. The OsA PX 2 and OsGST3 genes showed increased gene expression at 12 and 96 HAT for all herbicides. The OsHO -1 gene had the most significant expression changes, with maximum expression levels at 24 HAT with bentazon and at 96 HAT with penoxsulam and cyhalofop-butyl. Overall, antioxidant system gene expression increased after the applica-tion of bentazon, penoxsulam, and cyhalofop-butyl in ric