Selective Phytotoxic Effects of Sesquiterpenoids from Sonchus arvensis as a Preliminary Approach for the Biocontrol of Two Problematic Weeds of Wheat

Abstract

The objective of this study is to find new selective allelochemicals for managing two problematic weeds redroot pigweed (Amaranthus retrof lexus) and common lambsquarters (Chenopodium album) with minimal negative effects on wheat, thereby facilitating the development of eco-friendly botanical herbicide. Three new sesquiterpenoids, sonarvenolide A−C (1−3), and nine known sesquiterpenoids (4−12) were isolated from Sonchus arvensis. Compound 1 was a rare peroxide-substituted eudesmane-type sesquiterpenoid, and compound 3 was a rare iphionane-type sesquiterpenoid. Notably, compounds 1, 3, 4, 6−8, and 11 showed selectivity phytotoxic activity. In particular, compounds 1, 3, and 4 exhibited excellent germination inhibitory effect on A. retroflexus (IC 50 = 32.0−129.0 μM), higher than that of the positive control triasulfuron (IC 50 = 141.7 μM), and compound 4 showed excellent inhibition on C. album (IC 50 = 82.0 μM), higher than that of triasulfuron (IC 50 = 100.9 μM). In addition, compounds 1, 3, and 4 showed allelopathy to the growth of two weeds, which were more potent than or close to that of triasulfuron. Furthermore, these compounds were not toxic to wheat even at a high concentration (1000 μM). Structure−activity relationships (SARs) revealed that the presence of peroxides or the absence of hydroxyl at C-5 in the eudesmane-type sesquiterpenoids could strengthen the inhibitory activities. The discovery of selective allelochemicals provides not only a new choice to control two problematic weeds of wheat but also new natural lead compounds for herbicides.

Isolation, Characterization, and Bioherbicidal Potential of the 16-Residue Peptaibols from Emericellopsis sp. XJ1056

“…The phytotoxic activities of compounds 1 – 6 were assessed on A. retroflexus seeds using the Petri dish assay with minor modifications. , Briefly, the seeds were pretreated with 0.2% sodium hypochlorite for 15 min and then soaked in flowing water for 18 h. The wet seeds were germinated on moist filter paper under dark conditions. The isolated fractions and purified compounds were dissolved in 5 mL of methanol and subsequently diluted with 95 mL of water.…”

“…Fungi have evolved to produce a vast array of structurally diverse and biologically active secondary metabolites (natural products), which serve various ecological functions, including antimicrobial defense, competition for resources, and pathogenicity development . Many of these natural products are phytotoxins that play an important role in inducing disease symptoms in crops and weeds. − These phytotoxic natural products are often host-selective, feature unique MOAs distinct from synthetic herbicides, and are generally susceptible to microbial degradation . As a result, they are considered promising bioherbicides that may reduce the dependence on synthetic herbicides.…”

Secondary Metabolites from Aspergillus sparsus NBERC_28952 and Their Herbicidal Activities

“…crusgalli , and a dicotyledonous weed, A . retroflexus , using a Perish dish bioassay [ 29 , 30 ]. Distilled water was used as a negative control, while 2,4-D was used as a positive control.…”

Design, Synthesis, Structure–Activity Relationship, and Three-Dimensional Quantitative Structure–Activity Relationship of Fusarium Acid Derivatives and Analogues as Potential Fungicides

“…FA Derivative Toxicity Test on Plants. On the basis of previously published studies, 42,43 rice seeds were washed with sterile water and then placed in an incubator for 24 h in the dark. Rice seeds were then soaked in 1% NaOCl solution for 3−5 min for disinfection and washed with sterile water.…”