Involvement of miRNAs in Metabolic Herbicide Resistance to Bispyribac-Sodium in Echinochloa crus-galli (L.) P. Beauv.

Abstract

Several mechanisms involved in weed herbicide resistance are unknown, particularly those acting at the epigenetic level, such as the capacity of small-non-coding RNAs (sncRNAs) to target messenger RNAs of genes involved in herbicide detoxification. The transcription of these sncRNAs is stimulated by epigenetic factors, thereby affecting gene expression. This study was carried out in order to evaluate, for the first time in Echinochloa crus-galli (L.) P. Beauv. (barnyardgrass), the capacity of miRNAs to regulate the expression of genes associated with bispyribac-sodium detoxification. The expression profiles of eight miRNAs with a high degree of complementarity (≥80%) with mRNAs of genes involved in herbicide detoxification (CYP450, GST and eIF4B) were determined by qRT-PCR before and after herbicide spraying. Five of the miRNAs studied (gra-miR7487c, gma-miR396f, gra-miR8759, osa-miR395f, ath-miR847) showed an increased expression after herbicide application in both susceptible and resistant biotypes. All the miRNAs, except gra-miR8759, were more highly expressed in the herbicide-resistant biotypes. In specimens with increased expression of miRNAs, we observed reduced expression of the target genes. The remaining three miRNAs (ata-miR166c-5p, ath-miR396b-5p and osa-miR5538) showed no over-expression after herbicide treatment, and no difference in expression was recorded between susceptible and resistant biotypes. Our results represent a first overview of the capacity of miRNAs to regulate the expression of genes involved in bispyribac-sodium detoxification in the genus Echinochloa. Further research is required to identify novel miRNAs and target genes to develop more focused and sustainable strategies of weed control.

Incidence of resistance to ALS and ACCase inhibitors in Echinochloa species and soil microbial composition in Northern Italy

“…survived chemical control are listed in Table 3 . Herbicide resistance was tested according to Cusaro 13 : (i) controlled green-house growth trials were performed applying the same herbicides used in fields; (ii) plants were maintained in a growth chamber with a mean temperature of 20 °C, a relative humidity of 70% and a photoperiod of 14/10 h (day/night); (iii) three weeks after treatment, the sensitivity/resistance of plants to herbicides was tested following European and Mediterranean Plant Protection Organization (EPPO) standards 68 .…”

“…Furthermore, other factors may influence herbicide resistance, such as epigenetic mechanisms (i.e. miRNAs) regulating the expression of genes encoding for enzymes involved in xenobiotic detoxification 13 . Environmental traits may also be related to the occurrence of herbicide resistance, such as the rise of temperature 14 which could affect chemical control efficacy.…”