RESUMEN

Echinochloa crus-galli (L.) P. Beauv is a monocotyledonous weed that seriously infests rice fields. Florpyrauxifen-benzyl, a novel synthetic auxin herbicide commercialized in China in 2018, is an herbicide for controlling E. crus-galli. However, a suspected resistant population (R) collected in 2012 showed resistance to the previously unused florpyrauxifen-benzyl. Whole-plant dose-response bioassay indicated that the R population evolved high resistance to quinclorac and florpyrauxifen-benzyl. Pretreatment with P450 inhibitors did not influence the GR50 of E. crus-galli to florpyrauxifen-benzyl. The expression of target receptor EcAFB4 was down-regulated in the R population, leading to the reduced response to florpyrauxifen-benzyl (suppresses over-production of ethylene and ABA). We verified this resistance mechanism in the knockout OsAFB4 in Oryza sativa L. The Osafb4 mutants exhibited high resistance to florpyrauxifen-benzyl and moderate resistance to quinclorac. Furthermore, DNA methylation in the EcAFB4 promoter regulated its low expression in the R population after florpyrauxifen-benzyl treatment. In summary, the low expression of the auxin receptor EcAFB4 confers target resistance to the synthetic auxin herbicide florpyrauxifen-benzyl in the R- E. crus-galli.

Asunto(s)

Echinochloa , Resistencia a los Herbicidas , Herbicidas , Proteínas de Plantas , Echinochloa/efectos de los fármacos , Echinochloa/genética , Echinochloa/metabolismo , Herbicidas/farmacología , Resistencia a los Herbicidas/genética , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo , Receptores de Superficie Celular/metabolismo , Receptores de Superficie Celular/genética , Oryza/genética , Oryza/metabolismo , Oryza/efectos de los fármacos , Regulación de la Expresión Génica de las Plantas/efectos de los fármacos , Ácidos Indolacéticos/metabolismo , Ácidos Indolacéticos/farmacología , Quinolinas/farmacología , Malezas/efectos de los fármacos , Malezas/genética , Malezas/metabolismo

RESUMEN

Herbicides are essential for farmers to control weed. However, prolonged use of herbicides has caused the development of herbicide resistance in weeds. Here, the resistant Echinochloa crus-galli (RL5) was obtained by continuous treatment with metamifop for five generations in paddy fields. RL5 plants showed a 13.7-fold higher resistance to metamifop compared to susceptible E. crus-galli (SL5) plants. Pre-treatment with GST inhibitor (NBD-Cl) significantly increased the susceptibility of RL5 plants to metamifop. Faster metamifop metabolism and higher GST activity in RL5 plants than in SL5 plants were also confirmed, highlighting the role of GST in metabolic resistance. RNA-Seq analysis identified EcGSTU23 as a candidate gene, and this gene was up-regulated in RL5 and field-resistant E. crus-galli plants. Furthermore, the EcGSTU23 gene was overexpressed in the transgenic EcGSTU23-Maize, and the EcGSTU23-Maize showed resistance to metamifop. In vitro metabolic studies also revealed that the purified EcGSTU23 displayed catalytic activity in glutathione (GSH) conjugation, and metamifop was rapidly metabolized in the co-incubation system containing EcGSTU23 protein. These results provide direct experimental evidence of EcGSTU23's involvement in the metabolic resistance of E. crus-galli to metamifop. Understanding the resistance mechanism can help in devising effective strategies to combat herbicide resistance and breeding of genetically modified herbicide resistant crops.

Asunto(s)

Echinochloa , Glutatión Transferasa , Resistencia a los Herbicidas , Echinochloa/efectos de los fármacos , Echinochloa/genética , Glutatión Transferasa/genética , Glutatión Transferasa/metabolismo , Resistencia a los Herbicidas/genética , Herbicidas/farmacología , Regulación de la Expresión Génica de las Plantas/efectos de los fármacos , Plantas Modificadas Genéticamente , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo

RESUMEN

Photosynthesis system II (PS II) is an important target for the development of bioherbicides. In this study, a series of natural naphthoquinone derivatives containing diaryl ether were designed and synthesized based on the binding model of lawsone and PS II D1. Bioassays exhibited that most compounds had more than 80% inhibition of Portulaca oleracea and Echinochloa crusgalli roots at a dose of 100 µg/mL and compounds B4, B5, and C3 exhibited superior herbicidal activities against dicotyledonous and monocotyledon weeds to commercial atrazine. In particular, compound B5 exhibited excellent herbicidal activity at a dosage of 150 g a.i./ha. In addition, compared with atrazine, compound B5 causes less damage to crops. Molecular docking studies revealed that compound B5 effectively interacted with Pisum sativum PS II D1 via diverse interaction models, such as π-π stacking and hydrogen bonds. Molecular dynamics simulation studies and chlorophyll fluorescence measurements revealed that compound B5 acted on PS II. This is the first report of natural naphthoquinone derivatives targeting PS II and compound B5 may be a candidate molecule for the development of new herbicides targeting PS II.

Asunto(s)

Diseño de Fármacos , Echinochloa , Herbicidas , Simulación del Acoplamiento Molecular , Naftoquinonas , Malezas , Herbicidas/química , Herbicidas/farmacología , Herbicidas/síntesis química , Naftoquinonas/química , Naftoquinonas/farmacología , Echinochloa/efectos de los fármacos , Echinochloa/crecimiento & desarrollo , Malezas/efectos de los fármacos , Malezas/crecimiento & desarrollo , Relación Estructura-Actividad , Éteres/química , Éteres/farmacología , Complejo de Proteína del Fotosistema II/química , Complejo de Proteína del Fotosistema II/antagonistas & inhibidores , Complejo de Proteína del Fotosistema II/metabolismo , Estructura Molecular , Proteínas de Plantas/química , Raíces de Plantas/química , Raíces de Plantas/efectos de los fármacos

RESUMEN

The biochemical response of plants exposed to pesticides and inoculated with microorganisms is of great importance to explore cleaning up strategies for contaminated sites with pyrethroid-based pesticides. We evaluated the effects of a Trichoderma consortium on the biochemical responses of Echinochloa polystachya plants during the removal of a pyrethroid-based pesticide. Plants were inoculated or not with the Trichoderma consortium and exposed to commercial pesticide H24®, based on pyrethroids. Pesticide application resulted in significant reduction in root protein content (58%), but enhanced content of malondialdehyde (MDA) in shoots, superoxide dismutase (SOD) activity in shoots and roots, and catalase (CAT) activity in roots. Inoculation of Trichoderma consortium in E. polystachya exposed to the pesticide resulted in increased protein content in roots and MDA content in shoots (2-fold). Trichoderma consortium improved protein content and SOD activity (140-fold) in plants. Fungal inoculation increased the removal (97.9%) of the pesticide in comparison to the sole effect of plants (33.9%). Results allow further understanding about the responses of the interaction between plants and root-associated fungi to improving the assisted-phytoremediation of solid matrices contaminated with organic pesticides.

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This original paper describes the positive role of the Trichoderma sp. consortium on favoring the removal of a pyretrhoid-based pesticide. This is one of first reports on analyzing the influence of a Trichoderma consortium on the oxidative stress and antioxidant response of Echinochloa polystachya in presence of the pesticide. This experimental approach provides a new alternative for further fungal assisted-phytoremediation of a pyretrhoid-based pesticide.

Asunto(s)

Biodegradación Ambiental , Echinochloa , Piretrinas , Trichoderma , Piretrinas/metabolismo , Trichoderma/fisiología , Contaminantes del Suelo/metabolismo , Raíces de Plantas/microbiología , Raíces de Plantas/metabolismo , Malondialdehído/metabolismo , Superóxido Dismutasa/metabolismo , Plaguicidas/metabolismo

RESUMEN

BACKGROUND: The presence of barnyardgrass poses a threat to global food security by reducing rice yields. Currently, herbicides are primarily applied for weed management. However, the effectiveness of herbicide deposition and uptake on barnyardgrass is limited as a consequence of the high wax content on leaves, low water solubility and extreme lipophilicity of herbicides. Therefore, it is imperative to develop novel formulations for efficient delivery of herbicides to improve herbicidal activity and reduce dosage. RESULTS: We successfully prepared nanosuspension(s) (NS) of quinclorac through the wet media milling technique. This NS demonstrates excellent physical stability and maintains nanoscale during dose transfer. The deposition concentration and uptake concentration of NS on barnyardgrass were 3.84-4.47- and 2.11-2.58-fold greater than those traditional formulations, respectively. Moreover, the NS exhibited enhanced herbicidal activity against barnyardgrass at half the dosage required by conventional formulations without compromising rice safety. CONCLUSIONS: These findings suggest that NS can effectively facilitate the delivery of hydrophobic and poorly water-soluble herbicide active ingredients, thereby enhancing their deposition, uptake and bioactivity. This study expands the potential application of NS in pesticide delivery, which can provide valuable support for optimizing pesticide utilization, improving economic efficiency and mitigating environmental risks. © 2024 Society of Chemical Industry.

Asunto(s)

Herbicidas , Quinolinas , Herbicidas/química , Herbicidas/farmacología , Quinolinas/química , Quinolinas/farmacología , Suspensiones , Nanopartículas/química , Echinochloa/efectos de los fármacos , Control de Malezas/métodos

RESUMEN

Echinochloa crus-galli is a serious weed species in rice paddies. To obtain a new potential bioherbicide, we evaluated the inhibitory activities of 13 essential oils and their active substances against E. crus-galli. Essential oil from Syzygium aromaticum (L.) Merr. & L. M. Perry (SAEO) exhibited the highest herbicidal activity (EC50 = 3.87 mg mL-1) among the 13 essential oils evaluated. The SAEO was isolated at six different temperatures by vacuum fractional distillation, including 164°C, 165°C (SAEO-165), 169°C, 170°C 175°C and 180°C. The SAEO-165 had the highest inhibitory rate against E. crus-galli. Gas chromatography-mass spectrometry and high phase liquid chromatography identified eugenol (EC50 = 4.07 mg mL-1), α-caryophyllene (EC50 = 17.34 mg mL-1) and ß-caryophyllene (EC50 = 96.66 mg mL-1) as the three compounds in SAEO. Results from a safety bioassay showed that the tolerance of rice seedling (~ 20% inhibition) was higher than that of E. crus-galli (~ 70% inhibition) under SAEO stress. SAEO induced excessive generation of reactive oxygen species leading to oxidative stress and ultimately tissue damage in E. crus-galli. Our results indicate that SAEO has a potential for development into a new selective bio-herbicide. They also provide an example of a sustainable management strategy for E. crus-galli in rice paddies.

Asunto(s)

Echinochloa , Herbicidas , Aceites Volátiles , Syzygium , Aceites Volátiles/farmacología , Aceites Volátiles/química , Echinochloa/efectos de los fármacos , Syzygium/química , Herbicidas/farmacología , Herbicidas/química , Cromatografía de Gases y Espectrometría de Masas

RESUMEN

Tripyrasulfone is currently the only HPPD-inhibiting herbicide that possesses outstanding selectivity even for direct-seeded rice (Oryza sativa) when applied POST to control grass weeds; however, the underlying mechanisms remain unclear. In this study, the inhibitory effects of the real active HDT of tripyrasulfone on recombinant 4-hydroxyphenylpyruvate dioxygenase (HPPDs) from rice and barnyard grass (Echinochloa crus-galli) were similar, with consistent structural interactions and similar binding energies predicted by molecular docking. However, the HPPD expression level in rice was significantly greater than that in barnyard grass after tripyrasulfone treatment. Tripyrasulfone was rapidly taken up and hydrolyzed into HDT, which was similarly distributed within the whole plants of rice and barnyard grass at 24 h after treatment. Compared with barnyard grass, rice has more uniform epicuticular wax in the cuticle of its leaves, absorbing less tripyrasulfone and metabolizing much more tripyrasulfone. Overall, to a greater extent, the different sensitivities to tripyrasulfone between barnyard grass and rice resulted from metabolic variations.

Asunto(s)

4-Hidroxifenilpiruvato Dioxigenasa , Echinochloa , Herbicidas , Simulación del Acoplamiento Molecular , Oryza , Proteínas de Plantas , Oryza/metabolismo , Oryza/química , Echinochloa/efectos de los fármacos , Echinochloa/genética , Echinochloa/metabolismo , Echinochloa/crecimiento & desarrollo , Echinochloa/química , Herbicidas/farmacología , Herbicidas/química , Herbicidas/metabolismo , Proteínas de Plantas/metabolismo , Proteínas de Plantas/genética , Proteínas de Plantas/química , 4-Hidroxifenilpiruvato Dioxigenasa/metabolismo , 4-Hidroxifenilpiruvato Dioxigenasa/antagonistas & inhibidores , 4-Hidroxifenilpiruvato Dioxigenasa/genética , 4-Hidroxifenilpiruvato Dioxigenasa/química , Malezas/efectos de los fármacos , Malezas/metabolismo , Inhibidores Enzimáticos/farmacología , Inhibidores Enzimáticos/química

RESUMEN

The increasing amount of weeds surviving herbicide represents a very serious problem for crop management. The interaction between microbial community of soil and herbicide resistance, along with the potential evolutive consequences, are still poorly known and need to be investigated to better understand the impact on agricultural management. In our study, we analyzed the microbial composition of soils in 32 farms, located in the Northern Italy rice-growing area (Lombardy) with the aim to evaluate the relationship between the microbial composition and the incidence of resistance to acetolactate synthase (ALS) and acetyl-CoA carboxylase (ACCase) inhibiting herbicides in Echinochloa species. We observed that the coverage of weeds survived herbicide treatment was higher than 60% in paddy fields with a low microbial biodiversity and less than 5% in those with a high microbial biodiversity. Fungal communities showed a greater reduction in richness than Bacteria. In soils with a reduced microbial diversity, a significant increase of some bacterial and fungal orders (i.e. Lactobacillales, Malasseziales and Diaporthales) was observed. Interestingly, we identified two different microbial profiles linked to the two conditions: high incidence of herbicide resistance (H-HeR) and low incidence of herbicide resistance (L-HeR). Overall, the results we obtained allow us to make hypotheses on the greater or lesser probability of herbicide resistance occurrence based on the composition of the soil microbiome and especially on the degree of biodiversity of the microbial communities.

Asunto(s)

Acetolactato Sintasa , Acetil-CoA Carboxilasa , Echinochloa , Resistencia a los Herbicidas , Herbicidas , Microbiología del Suelo , Italia/epidemiología , Herbicidas/farmacología , Acetolactato Sintasa/antagonistas & inhibidores , Acetolactato Sintasa/genética , Echinochloa/efectos de los fármacos , Acetil-CoA Carboxilasa/genética , Acetil-CoA Carboxilasa/antagonistas & inhibidores , Malezas/efectos de los fármacos , Microbiota/efectos de los fármacos , Biodiversidad , Bacterias/efectos de los fármacos , Bacterias/genética , Bacterias/aislamiento & purificación , Bacterias/clasificación , Suelo/química , Hongos/efectos de los fármacos , Hongos/aislamiento & purificación , Hongos/genética

RESUMEN

Phytoene desaturase (PDS) is a critical functional enzyme in blocking ζ-carotene biosynthesis and is one of the bleaching herbicide targets. At present, norflurazon (NRF) is the only commercial pyridazine herbicide targeting PDS. Therefore, developing new and diverse pyridazine herbicides targeting PDS is urgently required. In this study, diflufenican (BF) was used as the lead compound, and a scaffold-hopping strategy was employed to design and synthesize some pyridazine derivatives based on the action mode of BF and PDS. The preemergence herbicidal activity tests revealed that compound 6-chloro-N-(2,4-difluorophenyl)-3-(3-(trifluoromethyl)phenoxy)pyridazine-4-carboxamide (B1) with 2,4-diF substitution in the benzeneamino ring showed 100% inhibition rates against the roots and stems of Echinochloa crus-galli and Portulaca oleracea at 100 µg/mL, superior to the inhibition rates of BF. Meanwhile, compound B1 demonstrated excellent postemergence herbicidal activity against broadleaf weeds, which was similar to that of BF (inhibition rate of 100%) but superior to that of NRF. This indicated that 6-Cl in the pyridazine ring is the key group for postemergence herbicidal activity. In addition, compound B1 could induce downregulation of PDS gene expression, 15-cis-phytoene accumulation, and Y(II) deficiency and prevent photosynthesis. Therefore, B1 can be considered as a promising candidate for developing high-efficiency PDS inhibitors.

Asunto(s)

Echinochloa , Herbicidas , Oxidorreductasas , Proteínas de Plantas , Malezas , Piridazinas , Herbicidas/farmacología , Herbicidas/química , Piridazinas/farmacología , Piridazinas/química , Echinochloa/efectos de los fármacos , Echinochloa/enzimología , Echinochloa/genética , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo , Proteínas de Plantas/química , Proteínas de Plantas/antagonistas & inhibidores , Oxidorreductasas/genética , Oxidorreductasas/metabolismo , Oxidorreductasas/antagonistas & inhibidores , Oxidorreductasas/química , Malezas/efectos de los fármacos , Malezas/enzimología , Malezas/genética , Relación Estructura-Actividad , Inhibidores Enzimáticos/farmacología , Inhibidores Enzimáticos/química , Raíces de Plantas/química , Raíces de Plantas/efectos de los fármacos , Estructura Molecular

RESUMEN

This study investigated the multiple herbicide resistance (MHR) mechanism of one Echinochloa crus-galli population that was resistant to florpyrauxifen-benzyl (FPB), cyhalofop-butyl (CHB), and penoxsulam (PEX). This population carried an Ala-122-Asn mutation in the acetolactate synthase (ALS) gene but no mutation in acetyl-CoA carboxylase (ACCase) and transport inhibitor response1 (TIR1) genes. The metabolism rate of PEX was 2-fold higher, and the production of florpyrauxifen-acid and cyhalofop-acid was lower in the resistant population. Malathion and 4-chloro-7-nitrobenzoxadiazole (NBD-Cl) could reverse the resistance, suggesting that cytochrome P450 (CYP450) and glutathione S-transferase (GST) contribute to the enhanced metabolism. According to RNA-seq and qRT-PCR validation, two CYP450 genes (CYP71C42 and CYP71D55), one GST gene (GSTT2), two glycosyltransferase genes (rhamnosyltransferase 1 and IAAGLU), and two ABC transporter genes (ABCG1 and ABCG25) were induced by CHB, FPB, and PEX in the resistant population. This study revealed that the target mutant and enhanced metabolism were involved in the MHR mechanism in E. crus-galli.

Asunto(s)

Sistema Enzimático del Citocromo P-450 , Echinochloa , Resistencia a los Herbicidas , Herbicidas , Mutación , Proteínas de Plantas , Resistencia a los Herbicidas/genética , Herbicidas/farmacología , Herbicidas/metabolismo , Echinochloa/genética , Echinochloa/efectos de los fármacos , Echinochloa/metabolismo , Echinochloa/crecimiento & desarrollo , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo , Sistema Enzimático del Citocromo P-450/genética , Sistema Enzimático del Citocromo P-450/metabolismo , Acetil-CoA Carboxilasa/genética , Acetil-CoA Carboxilasa/metabolismo , Malezas/efectos de los fármacos , Malezas/genética , Malezas/metabolismo , Acetolactato Sintasa/genética , Acetolactato Sintasa/metabolismo , Butanos , Nitrilos , Sulfonamidas , Uridina/análogos & derivados

RESUMEN

Scirpophaga incertulas Walker (Lepidoptera: Crambidae, yellow stem borer, YSB) is a monophagous insect pest that causes significant yield loss in rice (Oryza staiva L.). Semiochemical based pest management is being sought as an alternate to chemical pesticides to reduce pesticide footprints. We hypothesized differential release of volatiles from host rice and two companion non-host weeds, Echinochloa colona and Echinochloa crus-galli could be responsible for oviposition and biology of YSB and these chemicals could be used for YSB management. Number of eggs laid, and number of larvae hatched were significantly higher in rice plant as compared to weeds. YSB could only form dead hearts in rice plants. YSB significantly preferred host-plant volatiles compared to the non-host plants both in choice and no-choice tests in an Y-tube olfactometer. 2-Hexenal, hexanal, 2,4-hexadienal, benzaldehyde, nonanal, methyl salicylate and decanal were found in the leaf volatolomes of both the host and non-host plants in HS-SPME-GC-MS (Headspace-Solid phase micro extraction-Gas chromatography-Mass spectrometer). Pentene-3-one, 2-pentyl furan, 2,4-heptadienal, 2-octenal, 2-octenol and menthol were present only in the non-host plants. Fourteen rice unique compounds were also detected. The built-in PCA (Principal Component Analysis) and PLS-DA (Partial least squares-discriminant analysis) analysis in the MS-DIAL tool showed that the volatiles emitted from TN1 formed a cluster distinct from Echinochloa spp. and 2-octenal was identified as a unique compound. Olfactometer bioassays using synthetic compounds showed that rice unique compounds, like xylene, hexanal served as attractants whereas non-host unique compounds, like 2-pentylfuran, 2-octenal acted as repellent. The results indicate that the rice unique compounds xylene, hexanal along with other volatile compounds could be responsible for higher preference of YSB towards rice plants. Similarly, the non-host unique compounds 2-pentylfuran, 2-octenal could possibly be responsible for lower preference and defence against YSB. These compounds could be utilised for devising traps for YSB monitoring and management.

Asunto(s)

Oryza , Compuestos Orgánicos Volátiles , Animales , Oryza/química , Oryza/metabolismo , Oryza/parasitología , Compuestos Orgánicos Volátiles/metabolismo , Compuestos Orgánicos Volátiles/química , Compuestos Orgánicos Volátiles/farmacología , Compuestos Orgánicos Volátiles/análisis , Cromatografía de Gases y Espectrometría de Masas , Mariposas Nocturnas/fisiología , Oviposición/efectos de los fármacos , Echinochloa/química , Echinochloa/efectos de los fármacos , Femenino , Larva/fisiología , Microextracción en Fase Sólida , Hojas de la Planta/química , Hojas de la Planta/metabolismo , Malezas , Olfatometría

RESUMEN

In this work, a series of pyrrolidinone-containing 2-phenylpyridine derivatives were synthesized and evaluated as novel protoporphyrinogen IX oxidase (PPO, EC 1.3.3.4) inhibitors for herbicide development. At 150 g ai/ha, compounds 4d, 4f, and 4l can inhibit the grassy weeds of Echinochloa crus-galli (EC), Digitaria sanguinalis (DS), and Lolium perenne (LP) with a range of 60 to 90%. Remarkably, at 9.375 g ai/ha, these compounds showed 100% inhibition effects against broadleaf weeds of Amaranthus retroflexus (AR) and Abutilon theophrasti (AT), which were comparable to the performance of the commercial herbicides flumioxazin (FLU) and saflufenacil (SAF) and better than that of acifluorfen (ACI). Molecular docking analyses revealed significant hydrogen bonding and π-π stacking interactions between compounds 4d and 4l with Arg98, Asn67, and Phe392, respectively. Additionally, representative compounds were chosen for in vivo assessment of PPO inhibitory activity, with compounds 4d, 4f, and 4l demonstrating excellent inhibitory effects. Notably, compounds 4d and 4l induced the accumulation of reactive oxygen species (ROS) and a reduction in the chlorophyll (Chl) content. Consequently, compounds 4d, 4f, and 4l are promising lead candidates for the development of novel PPO herbicides.

Asunto(s)

Diseño de Fármacos , Inhibidores Enzimáticos , Herbicidas , Simulación del Acoplamiento Molecular , Malezas , Protoporfirinógeno-Oxidasa , Pirrolidinonas , Protoporfirinógeno-Oxidasa/antagonistas & inhibidores , Protoporfirinógeno-Oxidasa/química , Protoporfirinógeno-Oxidasa/metabolismo , Herbicidas/farmacología , Herbicidas/química , Herbicidas/síntesis química , Malezas/efectos de los fármacos , Malezas/enzimología , Inhibidores Enzimáticos/química , Inhibidores Enzimáticos/farmacología , Inhibidores Enzimáticos/síntesis química , Relación Estructura-Actividad , Pirrolidinonas/química , Pirrolidinonas/farmacología , Pirrolidinonas/síntesis química , Proteínas de Plantas/química , Proteínas de Plantas/antagonistas & inhibidores , Piridinas/química , Piridinas/farmacología , Piridinas/síntesis química , Amaranthus/efectos de los fármacos , Amaranthus/química , Echinochloa/efectos de los fármacos , Echinochloa/enzimología , Digitaria/efectos de los fármacos , Digitaria/enzimología , Digitaria/química , Lolium/efectos de los fármacos , Lolium/enzimología , Estructura Molecular

RESUMEN

BACKGROUND: Barnyardgrass (Weed Science Society of America recommended) or Barnyard grass (Britannica recommended) (Echinochloa crus-galli (L.) P. Beauv.) is one of the most problematic and dominant weeds in world agricultural systems, especially in paddy fields, where tillering and grain yield can be reduced by 50-70% because of its competitive pressure. The frequent use of chemical herbicides to control E. crus-galli has led to the evolution of herbicide resistance. Developing bioherbicides using pathogenic fungi to control E. crus-galli could be an alternative option. RESULTS: In a previous study we showed that a strain of Bipolaris yamadae (HXDC-1-2) was promising in controlling gramineous weeds. Here we present a study that evaluated this fungus as a mycoherbicide against E. crus-galli in greenhouse and paddy fields, characterized mycelium growth and conidial production, and examined the infection development. The median effective dose (ED50) and 90% effective dose (ED90) values of microcapsulated B. yamadae strain HXDC-1-2 on E. crus-galli in the greenhouse were 7.17 × 102 and 9.35 × 103 conidia mL-1, respectively. Conidial germination, mycelial growth, and attachment formation occurred on E. crus-galli leaves within 1 to 6 h. The hyphae directly invaded cells and stomata, primarily from the appressorium on the epidermis, and necrotic lesions were observed on the leaf surface within 20 to 24 h. Applied to E. crus-galli plants at 1 × 105 conidia mL-1, the fungus reduced the weed's fresh weight of 75%. CONCLUSION: B. yamadae strain HXDC-1-2 has the potential to be developed as a bioherbicide against E. crus-galli plants, especially in rice fields. © 2024 Society of Chemical Industry.

Asunto(s)

Bipolaris , Echinochloa , Oryza , Malezas , Control de Malezas , Echinochloa/efectos de los fármacos , Echinochloa/crecimiento & desarrollo , Oryza/microbiología , Control de Malezas/métodos , Malezas/efectos de los fármacos , Bipolaris/efectos de los fármacos , Control Biológico de Vectores , Herbicidas/farmacología

RESUMEN

A proper formulation is crucial to improve the herbicidal effects of essential oils and their selectivity. In this study, we investigated the physicochemical properties of bio-based nanoemulsions (CNs) containing several concentrations of caraway (Carum carvi) essential oil stabilized with Eco Tween 80, as a surfactant, maintaining 1:1 proportions. Detailed physicochemical characteristics of the CNs revealed that their properties were most desired at 2% of the oil and surfactant, i.e., the smallest droplet size, polydispersity index, and viscosity. The CNs caused biochemical changes in maize and barnyard grass (Echinochloa crus-galli) seedlings, however, to a different extent. Barnyard grass has overall metabolism (measured as a thermal power) decreased by 39-82% when exposed to the CNs. The CNs triggered changes in the content and composition of carbohydrates in the endosperm of both species' seedlings in a dose-response manner. The foliar application of CNs caused significant damage to tissues of young maize and barnyard grass plants. The effective dose of the CN (ED50, causing a 50% damage) was 5% and 17.5% oil in CN for barnyard grass and maize tissues, respectively. Spraying CNs also decreased relative water content in leaves and affected the efficiency of photosynthesis by disturbing the electron transport chain. We found that barnyard grass was significantly more susceptible to the foliar application of CNs than maize, which could be used to selectively control this species in maize crops. However, further studies are needed to verify this hypothesis under field conditions.

Asunto(s)

Carum , Echinochloa , Aceites Volátiles , Zea mays , Aceites de Plantas/farmacología , Aceites Volátiles/farmacología , Aceites Volátiles/química , Plantones , Tensoactivos/farmacología

RESUMEN

Rice (Oryza sativa L.) is a staple cereal in the diet of more than half of the world's population. Within the European Union, Spain is a leader in rice production due to its climate and tradition, accounting for 26% of total EU production in 2020. The Valencian rice area covers around 15,000 hectares and is strongly influenced by biotic and abiotic factors. An important biotic factor affecting rice production is weeds, which compete with rice for sunlight, water and nutrients. The dominant weed in Spain is Echinochloa spp., although wild rice is becoming increasingly important. Rice cultivation in Valencia takes place in the area of L'Albufera de Valencia, which is a natural park, i.e., a special protection area. In this natural area, the use of phytosanitary products is limited, so it is necessary to use the minimum amount possible. Therefore, the objective of this work is to evaluate the possibility of using remote sensing effectively to determine the effectiveness of the application of the herbicide cyhalofop-butyl by drone for the control of Echinochloa spp. in rice crops in Valencia. The results will be compared with those obtained by using sterilisation machines (electric backpack sprayers) to apply the herbicide. To evaluate the effectiveness of the application, the reflectance obtained by the satellite sensors in the red and near infrared (NIR) wavelengths, as well as the normalised difference vegetation index (NDVI), were used. The remote sensing results were analysed and complemented by the number of rice plants and weeds per area, plant dry weight, leaf area, BBCH phenological state, SPAD index values, chlorophyll content and relative growth rate. Remote sensing is validated as an effective tool for determining the efficacy of an herbicide in controlling weeds applied by both the drone and the electric backpack sprayer. The weeds slowed down their development after the treatment. Depending on the phenological state of the crop and the active ingredient of the herbicide, these results are applicable to other areas with different climatic and environmental conditions.

Asunto(s)

Echinochloa , Herbicidas , Oryza , Herbicidas/farmacología , España , Tecnología de Sensores Remotos , Dispositivos Aéreos No Tripulados , Malezas

RESUMEN

BACKGROUND: In paddy fields, the noxious weed barnyard grass secretes 2,4-dihydroxy-7-methoxy-2H-1,4-benzoxazin-3(4H)-one (DIMBOA) to interfere with rice growth. Rice is unable to synthesize DIMBOA. Rice cultivars with high or low levels of allelopathy may respond differently to DIMBOA. RESULTS: In this study, we found that low concentrations of DIMBOA (≤ 0.06 mM) promoted seedling growth in allelopathic rice PI312777, while DIMBOA (≤ 0.08 mM) had no significant influence on the nonallelopathic rice Lemont. DIMBOA treatment caused changes in the expression of a large number of glutathione S-transferase (GST) proteins, which resulting in enrichment of the glutathione metabolic pathway. This pathway facilitates plant detoxification of heterologous substances. The basal levels of GST activity in Lemont were significantly higher than those in PI312777, while GST activity in PI312777 was slightly induced by increasing DIMBOA concentrations. Overexpression of GST genes (Os09g0367700 and Os01g0949800) in these two cultivars enhanced rice resistance to DIMBOA. CONCLUSIONS: Taken together, our results indicated that different rice accessions with different levels of allelopathy have variable tolerance to DIMBOA. Lemont had higher GST activity, which helped it tolerate DIMBOA, while PI312777 had lower GST activity that was more inducible. The enhancement of GST expression facilitates rice tolerance to DIMBOA toxins from barnyard grass root exudates.

Asunto(s)

Benzoxazinas , Echinochloa , Oryza , Oryza/metabolismo , Malezas , Glutatión Transferasa/genética , Glutatión Transferasa/metabolismo

RESUMEN

The phytotoxicities of a selection of eudesmanolides and guaianolides, including natural products and new derivatives obtained by semisynthesis from plant-isolated sesquiterpene lactones, were evaluated in bioassays against three weeds of concern in agriculture (Amaranthus viridis L., Echinochloa crus-galli L., and Lolium perenne L.). Both eudesmanolides and guaianolides were active against the root and shoot growth of all the species, with the eudesmanolides generally showing improved activities. The IC50 values obtained for the herbicide employed as positive control (on root and shoot growth, respectively, A. viridis: 27.8 and 85.7 µM; E. crus-galli: 167.5 and 288.2 µM; L. perenne: 99.1 and 571.4 µM) were improved in most of the cases. Structure-activity relationships were discussed, finding that hydroxylation of the A-ring and C-13 as well as the position, number, and orientation of the hydroxyl groups and the presence of an unsaturated carbonyl group can significantly influence the level of phytotoxicity. γ-Cyclocostunolide was the most active compound in the series, followed by others such as dehydrozaluzanin C and α-cyclocostunolide (outstanding their IC50 values on A. viridis)─natural products that can therefore be suggested as models for herbicide development if further research indicates effectiveness on a larger scale and environmental safety in ecotoxicological assessments.

Asunto(s)

Amaranthus , Echinochloa , Herbicidas , Lolium , Sesquiterpenos , Malezas

RESUMEN

This study has redirected focus towards the untapped potential of millets, exploring their utilization as small-scale vegetables like sprouts and microgreens. This study assessed the metabolite profiles and therapeutic efficacy of barnyard millets as sprouts and microgreens for antioxidant, anti-diabetic, and bioaccessibility properties. Based on the study, sprouts contained 456.52 mg GE/g of starch and microgreens contained 470.04 mg GE/g of carbohydrates, whereas the gastric phase of microgreens showed 426.85 mg BSAE/g, 397.6 mg LE/g, 348.19 g RE/g, and 307.40 g AAE/g of proteins, amino acids, vitamin A and vitamin C respectively. Secondary metabolites were significantly concentrated in the microgreen stage which is responsible for their increased antioxidant and antidiabetic potential than sprouts. This study validated the therapeutic and nutritional value of millet sprouts and microgreens by demonstrating their significant nutritional composition.

Asunto(s)

Antioxidantes , Echinochloa , Antioxidantes/metabolismo , Echinochloa/química , Hipoglucemiantes , Vitaminas , Proteínas

RESUMEN

BACKGROUND: Recently, suspected cyhalofop-butyl-resistant populations of allohexaploid weed Echinochloa crus-galli var. crus-galli were discovered in rice fields in Aichi Prefecture, Japan. Analyzing the target-site ACCase genes of cyhalofop-butyl helps understand the resistance mechanism. However, in E. crus-galli, the presence of multiple ACCase genes and the lack of detailed gene investigations have complicated the analysis of target-site genes. Therefore, in this study, we characterized the herbicide response of E. crus-galli lines and thoroughly characterized the ACCase genes, including the evaluation of gene mutations in the ACCase genes of each line. RESULT: Four suspected resistant lines collected from Aichi Prefecture showed varying degrees of resistance to cyhalofop-butyl and other FOP-class ACCase inhibitors but were sensitive to herbicides with other modes of action. Through genomic analysis, six ACCase loci were identified in the E. crus-galli genome. We renamed each gene based on its syntenic relationship with other ACCase genes in the Poaceae species. RNA-sequencing analysis revealed that all ACCase genes, except the pseudogenized copy ACCase2A, were transcribed at a similar level in the shoots of E. crus-galli. Mutations known to confer resistance to FOP-class herbicides, that is W1999C, W2027C/S and I2041N, were found in all resistant lines in either ACCase1A, ACCase1B or ACCase2C. CONCLUSION: In this study, we found that the E. crus-galli lines were resistant exclusively to ACCase-inhibiting herbicides, with a target-site resistance mutation in the ACCase gene. Characterization of ACCase loci in E. crus-galli provides a basis for further research on ACCase herbicide resistance in Echinochloa spp. © 2023 The Authors. Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.

Asunto(s)

Butanos , Echinochloa , Herbicidas , Nitrilos , Echinochloa/genética , Japón , Herbicidas/farmacología , Resistencia a los Herbicidas/genética , Mutación

RESUMEN

Underwater germination could risk seedling survival, suggesting the need for control through seed perception of environmental cues. These cues include diurnally alternating temperatures tied to drained soils or shallow water tables. We examined high-amplitude alternating temperatures impact on underwater germination. Besides, the conditions experimented by seeds in the soil (e.g. hydration/dehydration phases) change their germinability so we tested if osmopriming could affect underwater germination. We worked with Echinochloa colona seedlots from extensive crop fields, exposing seeds to sequential submergence and drained treatments in combination with cues that promote germination. While a 10°C difference between maximum and minimum daily temperatures maximised germination in drained conditions, higher amplitudes (>15°C) alternating temperatures promoted E. colona underwater germination under hypoxic water (pO2 <4.1kPa). KNO3 osmopriming in drained conditions promoted later underwater germination even under hypoxic water; however, PEG 6000 osmopriming induced seeds to enter secondary dormancy inhibiting underwater germination. KNO3 improved E. colona underwater germination under air-equilibrated floodwater (pO2 : 16.5-17.4kPa) yet not under hypoxic conditions. This suggests that germination can proceed in flooded nitrate-fertile soils as long as it remains aerobic. Hypoxic submergence did not inhibit the induction of hypersensitivity to light in E. colona seeds. This research expands our understanding of wetland seed germination ecophysiology, shedding light on the inducible nature of underwater germination in hydrophyte weeds.

Asunto(s)

Echinochloa , Germinación , Germinación/fisiología , Echinochloa/fisiología , Nitratos/farmacología , Temperatura , Agua/farmacología , Semillas , Suelo