Understanding the responses of tillering to 2,4-D in Setaria viridis L

Abstract

Abstract Background Green foxtail [Setaria viridis (L.)] is one of the most abundant and troublesome annual grass weeds in alfalfa fields in Northeast China. Synthetic auxin herbicide is widely used in agriculture, while how auxin herbicide affects tillering on perennial grass weeds is still unclear. A greenhouse experiment was conducted to examine the effects of auxin herbicides 2,4-D on green foxtail growth, especially on tillers. Results In the study, 2,4-D isooctyl ester was used and there was an inhibition of plant height and fresh weight on green foxtail after application. The photosynthetic rate was dramatically reduced and there was an accumulation of MDA content. Moreover, applicating 2,4-D isooctyl ester significantly reduced the tillering buds at rates between 2100 and 8400 ga. i. ha-1. Transcriptome results showed that applying 2,4-D on leaves can affect the phytohormone signal transduction pathways in plant tillers. Among them, there were significant effects on auxin, cytokinin, abscisic acid, gibberellin, and brassinosteroid signaling. Indeed, external ABA and GA on leaves can also limit tillering in green foxtail. Conclusions These data will be helpful to further understand the responses of green foxtail to 2, 4-D isooctyl ester, which may provide a unique perspective for the development and identification of new target compounds that are effective against this weed species.