Herbicide stress‐induced miRNAs transcription changes in resistant Echinochloa crus‐galli (L.) P.Beauv. biotypes

In compliance with the European regulations concerning the placing of plant protection products on the market (Reg EC/1107/2009), repeated use of a narrow range of herbicides with similar modes of action has led to weed herbicide resistance evolution. Target site resistance (TSR), in which a DNA missense mutation is involved, and non‐target site resistance (NTSR), which occurs due to herbicide detoxification, are known to be the main re‐ sistance phenomena. Furthermore, it has been hypothesized how, under conditions of herbicide stress, epige‐ netics may contribute to the onset of herbicide resistance (Markus et al. 2018). Echinochloa crus‐galli (L.) P.Beauv. is a typical, but not exclusive, rice fields weed. It is highly adaptable and has developed herbicide resistance against many chemicals. These features make it very dangerous for agricultural yield (Cusaro et al. 2022a). To assess miRNAs transcription induction and their regulatory role towards genes involved in herbicide detoxifi‐ cation (CYP450, GST and eIF4B), hence resistance, miRNAs and genes expression profiling was analyzed by qRT‐ PCR before and after herbicide administration. Results showed that herbicide stimulates the transcription of some miRNAs. When miRNAs are over‐transcripted, they inhibit the expression of proteins involved in herbicide detoxification, leading to susceptibility. Instead, miRNAs under‐expression lead to enhanced protein expression and herbicide detoxification, hence resistance occurrence (Cusaro et al. 2022b). A thorough understanding of epigenetics regulation of genes acting in herbicide resistance, considering epigenetic–environment interactions, will contribute to improve precision weed management (PWM) technologies, favoring less impactful and more sustainable strategies to control herbicide resistance.