Transcriptome responses to the natural phytotoxin t‐chalcone in Arabidopsis thaliana L.

Abstract

BACKGROUND New modes of action are needed for herbicides. The flavonoid synthesis intermediate t‐chalcone causes apoptosis‐like symptoms in roots and bleaching of shoots of Arabidospsis, suggesting a unique mode of action as a phytotoxin. RESULTS Using RNA‐Seq, transcriptome changes were monitored in Arabidopsis seedlings during the first 24 h of exposure (at 1, 3, 6, 12 and 24 h) to 21 μm t‐chalcone (I50 dose), examining effects on roots and shoots separately. Expression of 892 and 1000 genes was affected in roots and shoots, respectively. According to biological classification, many of the affected genes were transcription factors and genes associated with oxidative stress, heat shock proteins, xenobiotic detoxification, ABA and auxin biosynthesis, and primary metabolic processess. These are secondary effects found with most phytotoxins. Potent phytotoxins usually act by inhibiting enzymes of primary metabolism. KEGG pathway analysis of transcriptome results from the first 3 h of t‐chalcone exposure indicated several potential primary metabolism target sites for t‐chalcone. Of these, p‐hydroxyphenylpyruvate dioxygenase (HPPD) and tyrosine amino transferase were consistent with the bleaching effect of the phytotoxin. Supplementation studies with Lemna paucicostata and Arabidiopsis supported HPPD as the target, although in vitro enzyme inhibition was not found. CONCLUSIONS t‐Chalcone is possibly a protoxin that is converted to a HPPD inhibitor in vivo. © 2019 Society of Chemical Industry

Rapid Reduction of Herbicide Susceptibility in Junglerice by Recurrent Selection with Sublethal Dose of Herbicides and Heat Stress

“…These results corroborate previous reports about HSPs and trehalose being important in plant adaptation and tolerance to various environmental stresses [94][95][96][97][98][99][100][101]. UDP-glucosyltransferases (UGT) is another group of genes involved in xenobiotic detoxification, which is also associated with auxin synthesis, signaling and response [86]. UGT may play a role in plant response to florpyrauxifen-benzyl as it was induced by the herbicide under both temperatures (Figure 3).…”

“…Plants are exposed to various biotic and abiotic conditions that, when exceeding the limits of fluctuations, can be deemed as stress [83,84]. The action of HSPs can be activated under various stress conditions including osmotic and oxidative stress, drought, salinity, extreme temperatures, pesticide response and multiple stress resistance, among others [25,[85][86][87][88][89]. The upregulation of HSP 12 h after application of all herbicides under both temperature treatments (30 and 45 • C), especially HSP15, indicates possible contribution to the adaptation to herbicides with different MOAs and thermotolerance.…”

“…UDP-glucosyltransferases (UGT) is another group of genes involved in xenobiotic detoxification, which is also associated with auxin synthesis, signaling and response [86]. UGT may play a role in plant response to florpyrauxifen-benzyl as it was induced by the herbicide under both temperatures (Figure 3).…”

ROS Metabolism Perturbation as an Element of Mode of Action of Allelochemicals

“…An example of a modern view to study the MOA of allelochemicals is the transcriptome analysis (RNA-Seq) of Arabidopsis plants treated with chalcone [ 78 ]. Chalcone is a precursor of flavonoids, present in many plants in which it is responsible for their yellow coloration.…”

“…The application of trans-chalcone to Arabidopsis plants led to an induction of oxidative stress and resulted in the stimulation of cell death, particularly in roots [ 77 ]. The numerous transcripts of genes involved in the response to oxidative stress and programmed cell death were up-regulated in roots of Arabidopsis [ 78 ]. Genes related to apoptosis, oxidative stress, and cell death were up-regulated in roots after a short-term treatment (1–6 h).…”