Eleusine Indica Research Articles

Effects of goosegrass (Eleusine indica) competition on strawberry growth and yield

Abstract Goosegrass [Eleusine indica (L.) Gaertn.] is one of the most problematic weeds in plasticulture strawberry [Fragaria × ananassa (Weston) Duchesne ex Rozier (pro sp.) [chiloenis × virginiana]] production systems in Florida. A 2-yr trial was implemented to evaluate the effects of different E. indica densities on strawberry growth and yield. Eleusine indica densities evaluated were 0, 0.4, 0.8, 1.9, 2.7, and 3.8 plants m−2 equally distributed on the plastic-mulched bed top within the strawberry transplant holes. Eleusine indica density did not affect E. indica height or biomass. However, E. indica seed production was positively correlated with E. indica density in Season 1 and negatively correlated with E. indica density in Season 2. A negative linear regression was observed between E. indica density and strawberry yield in both seasons. For each increase in E. indica plants per square meter, strawberry yield was reduced by 316 and 2,356 kg ha−1 for Seasons 1 and 2, respectively. Our results highlight the importance of achieving adequate E. indica management to minimize yield losses.

Minimized‐rate topramezone programs for goosegrass [Eleusine indica (L.) Gaertn.] control in Florida

AbstractGoosegrass [Eleusine indica (L.) Gaertn.] is one of the most troublesome warm‐season grassy weeds in subtropical climates of the southern United States. Currently, postemergence options are highly limited, and goosegrass control (GC) becomes more difficult as plants mature. Among current options, topramezone can control mature goosegrass. Research conducted in Florida suggests that despite seemingly effective control, recovery may be occurring from surviving roots. Therefore, this study assessed strategies aimed to ensure the persistent removal of mature goosegrass populations of Florida ecotypes. Two greenhouse studies were conducted to evaluate the response of goosegrass at one to three tillers and 4–10 tillers to topramezone applied once at rates from 0.8 to 12.2 g a.i. ha−1 (study 1) and at total rate reduced to 6.1 g a.i. ha−1 applied once or equally divided into two, four, or eight biweekly applications (study 2). Single topramezone applications at 6.1 g a.i. ha−1 provided comparable GC and biomass reduction to single applications at 12.2 g a.i. ha−1. Reduced rate‐based split‐programs of two and four biweekly applications improved GC and its persistence over a single application as evidenced by a >250 increase in GC area under the progress curve and a >20 days increase in days over 80% GC. Among the proposed extended application programs based on the reduced effective rate of topramezone, the most promising consists of four biweekly applications at a 0.125× rate, equivalent to 1.53 g a.i. ha−1.

Glyphosate Resistance in Eleusine indica: Involvement of CYP71AK44 in Addition to EPSPS Gene Overexpression.

Intensive application of glyphosate has resulted in resistance evolution in many weed populations, including Eleusine indica. This study characterized glyphosate resistance and investigated the underlying mechanisms in a glyphosate-resistant population (R-JX) of E. indica from China. The R-JX population was 8.5 times resistant to glyphosate relative to the glyphosate-susceptible population (SA). Point mutations were not observed in the target gene 5-enolypyruvyl-shikimate-3-phosphate synthase gene (EPSPS). However, the expression level and copy number of EPSPS were 8.8 times and 15.2 times, respectively, greater in R-JX than that in the SA population. Pre-application of the P450 inhibitor lowered the resistance level to glyphosate from 8.5 times to 3.6 times in the R-JX population. RNA-Seq and RT-qPCR revealed that the CYP71AK44 gene was consistently upregulated in R-JX and five other glyphosate-resistant populations. Rice calli and seedlings overexpressing CYP71AK44 showed glyphosate resistance. In conclusion, overexpression of the target EPSPS plus CYP71AK44 collectively contributes to glyphosate resistance in these E. indica populations.

Chemical Synthesis, Herbicidal Activity, Crop Safety, and Molecular Basis of ortho-Fluoroalkoxy Substituted Sulfonylureas as Novel Acetohydroxyacid Synthase Inhibitors.

In the face of increasing resistance to the currently used commercial herbicides and the lack of success in identifying new herbicide targets, alternative herbicides need to be developed to control unwanted monocotyledon grasses in food crops. Here, a panel of 29 novel sulfonylurea-based compounds with ortho-fluoroalkoxy substitutions at the phenyl ring were designed and synthesized. Pot assays demonstrated that two of these compounds, 6d and 6u, have strong herbicidal activities against Echinochloa crus-galli, Eleusine indica, Alopecurus aequalis, and Alopecurus japonicus Steudel at a dosage of 15 g ha-1. Furthermore, these two compounds exhibited <5% inhibition against wheat at a dosage of 30 g ha-1 under post-emergence conditions. 6u also exhibited <5% inhibition against rice at a dosage of 30 g ha-1 under both post-emergence and pre-emergence conditions. A kinetics study demonstrated that 6d and 6u are potent inhibitors of Arabidopsis thaliana acetohydroxyacid synthase (AHAS; EC 2.2.1.6) with potent Ki values of 18 ± 1.1 and 11.9 ± 4.0 nM, respectively. The crystal structure of 6u in complex with A. thaliana (At)AHAS has also been determined at 2.7 Å resolution. These new compounds represent new alternative herbicide choices to protect wheat or rice from invading grasses.

Determination of Potential Anti Quorum Sensing Activity of Eleusine indica Ethanolic Crude Extract against Escherichia coli and Staphylococcus aureus

Determination of Potential Anti Quorum Sensing Activity of Eleusine indica Ethanolic Crude Extract against Escherichia coli and Staphylococcus aureus

Unraveling the mechanisms of multiple resistance across glyphosate and glufosinate in Eleusine indica

The herbicides glyphosate and glufosinate are commonly used in citrus and sugarcane orchards in Guangxi Province, China, wherein the C4 plant Eleusine indica (L.) Gaertn. is known to be a dominant weed species. However, high selection pressure has resulted in failure of control. In the present study, experiments were conducted to clarify resistance levels for the suspected populations and elucidate the mechanisms for multiple resistance. The resistance index to glyphosate was calculated for eight populations and ranged from 5.4 to 21.3, with a low-level shikimate content of 0.24–0.50 μg g−1. In addition, three populations showed low-level resistance to glufosinate, with a resistance index ranging from 2.6 to 3.9. The amplification of the 5-enolpyruvylshikimate-3-phosphate synthase (EPSPS) gene with a double-mutation T102I + P106S (TIPS) or a single-mutation (P106S and P106A) was observed in most populations. The target genes of glufosinate (GS1–1, GS1–2, and GS1–3) showed high-level expression, namely 145.5-fold that of susceptible plants. The content of EPSPS and glutamine synthetase (GS) protein in resistant plants can reach to 3.6 and 2.1 times higher than those in susceptible plants, respectively. The overexpression of the EPSPS gene with double (T102I + P106S) or single (P106S and P106A) mutations, plus the overexpression of GS1–1, GS1–2, and GS1–3, responded to multiple resistance mechanisms. Altogether, these results demonstrate that overexpression of GS1 is a novel form of resistant mechanism to glufosinate in weeds.

Plant Agrobiodiversity, Agricultural and Phytosanitary Practices of Market Garden Crops in the Centre‐East Region of Burkina Faso

ABSTRACTIntroductionIn West Africa, market gardeners use various agricultural practices to increase yields. However, many of these practices do not comply with agroecological standards and cause intoxication, pollution, soil degradation and biodiversity loss. This study characterizes the plant agrobiodiversity of market garden crops grown during the rainy season and the agricultural and phytosanitary practices used for their management.Materials and MethodsThe study was carried out in Burkina Faso. Plant agrobiodiversity was assessed in 100 market gardens. Agricultural and phytosanitary practices were characterized using semi‐structured interviews. A Sankey diagram was used to highlight the relationships among market garden crops, bioaggressors and diseases. Principal component analyses were applied to highlight the agricultural and phytosanitary practices used.ResultsThe results revealed rich agrobiodiversity, including 16 market garden crops, 15 local agroforestry species, 17 planted species and 37 weed species. The main market garden crops grown in the rainy season were cabbage (20.30%), lettuce (16.62%), tomato (11.69%), and amaranth (10.15%). The most frequent agroforestry species were Azadirachta indica (18.20%) and Mangifera indica (15.03%). The most common weeds were Eleusine indica (11.02%) and Cyperus reduncus (9.70%). Eleven pests were identified, and the most frequently recorded were caterpillars (39.06%). Sixteen diseases were reported, the most common being leaf yellowing (15.67%) and leaf wilt (11.67%). Numerous market gardeners use mineral fertilizers such as Yaramila (NPK 23‐10‐5), NPK (14‐23‐14), urea (46.00% nitrogen), and liquid fertilizer as well as compost and organic manure. The most common agricultural practice was crop rotation (79.00%). To protect crops, 89.00% of producers used synthetic chemical pesticides in an uncontrolled manner, most of which are purchased on the local market. Only 11.00% of the market gardeners practiced the natural phytosanitary treatments.ConclusionThis study provides important information that can be used for the sustainable management of market gardens. Agroecological standards should be popularized to ensure food security for market garden crops.

Metproxybicyclone, a Novel Carbocyclic Aryl-dione Acetyl-CoA Carboxylase-Inhibiting Herbicide for the Management of Sensitive and Resistant Grass Weeds.

Postemergence control of grass weeds has become problematic due to the evolution of resistance to 5-enolpyruvylshikimate-3-phosphate synthase, acetyl-CoA carboxylase (ACCase), and acetolactate synthase-inhibiting herbicides. Herein we describe the invention and synthesis journey toward metproxybicyclone, the first commercial carbocyclic aryl-dione ACCase-inhibiting herbicide for the cost-effective management of grass weeds in dicotyledonous crops and in preplant burndown applications. Glasshouse and field experiments have shown that metproxybicyclone is safe for use on soybean, cotton, and sugar beet, among other crops. It is effective on a variety of key grass weeds including Eleusine indica, Digitaria insularis, Sorghum halepense, and Echinochloa crus-galli. Importantly, metproxybicyclone was more efficacious at killing resistant grass weed populations than current ACCase herbicides. Metproxybicyclone controlled the main ACCase target-site and nontarget site resistant mechanisms in characterized Lolium multiflorum and E. indica populations under glasshouse conditions. Excellent control of a broad resistance-causing D2078G target-site mutant E. indica population was also observed under field conditions.

Herbicidal Sorbicillinoid Analogs Cause Lignin Accumulation in Aspergillus aculeatus TE-65L.

Five new sorbicillinoid derivatives, including (±)-aspersorbicillin A [(±)-1], a pair of enantiomers at C-9, and aspersorbicillins B-D (2-4), together with two known analogs (5 and 6) were isolated from the endophytic fungus Aspergillus aculeatus TE-65L. Their structures including absolute configurations were determined by detailed spectroscopic analyses and electronic circular dichroism calculations. The herbicidal activity of sorbicillinoids on the germ and radicle elongation of various weed types was reported for the first time. Compound 1 displayed significant herbicidal activity against Eleusine indica germ elongation (IC50 = 28.8 μg/mL), while compound 6 inhibited radicle elongation (IC50 = 25.6 μg/mL). Both were stronger than those of glyphosate (66.2 and 30.9 μg/mL, respectively). Further transcriptomic and LC-MS/MS metabolomic analysis indicated that 6 induced the transcriptional expressions of genes related to the lignin biosynthetic pathway, resulting in lignin accumulation. Transmission electron microscopy confirmed the cell wall thickening of seeds treated with 6, suggesting weed growth inhibition. This study reveals new lead compounds for fabricating natural herbicides and expands the agricultural use of sorbicillinoid analogs.

Allelopathic effects of Borreria latifolia on weed germination and identification of allelochemicals.

Borreria latifolia (Aubl.) K. Schum (Rubiaceae) is an annual weed with a strong allelopathic inhibitory effect on malignant weeds in orchards in southern China. This study was carried out to investigate its allelopathic potential and to identify allelochemicals present in B. latifolia. Aqueous extracts of B. latifolia inhibited the germination and radicle growth of Eleusine indica and the radicle growth of Bidens alba in a dose-dependent manner. However, only the high-concentration treatment at 50 mg mL-1 delayed the germination of B. alba and Digitaria sanguinalis. Among the root, stem, and leaf aqueous extracts of B. latifolia, the leaf extract had the strongest inhibitory effects on the germination and seedling growth of E. indica, followed by stem extract and then root extract. A total of 47 published allelochemicals, including coumarin, 4-hydroxybenzoate, salicylic acid, 4-hydroxycinnamic acid, and vanillic acid, were identified in the leaf extract. Among the five allelochemicals, coumarin was found to be present in the highest concentration in the leaf extract. Furthermore, coumarin exhibited a significantly greater inhibitory effect on E. indica (EC50 = 36.87 mg L-1) than did the other allelochemicals (EC50 = 100.87-156.30 mg L-1). This study indicates that the leaf extracts of B. latifolia and their allelochemicals have excellent potential as bioherbicides and that coumarin is one of the key allelochemicals in B. latifolia. © 2024 Society of Chemical Industry.

Glyphosate isolado e em associação com herbicida para o controle e seletividade de plantas daninhas na cultura do algodão RF

Cotton (Gossypium hirsutum L.) is a fiber-producing plant that demonstrates high cultivation aptitude in Brazil. However, crop performance is influenced by factors such as weed interference, mainly due to the few options of selective herbicides to be applied in post-emergence in cotton cultivars with RF technology. Thus, the objective of this study was to evaluate the use of glyphosate associated with latifolicides for weed management in cotton crops. For this, a field experiment was carried out, in a randomized block design with 13 tracts and four replications, using cv. Deltapine DP1857B3RF. The treatments were composed of pyrithiobac-sodium at doses (36.4, 42.0 and 50.4 g a.i. ha-1), trifloxysulfuron-sodium (2.25, 2.62 and 3.0 g a.i. ha-1), glyphosate isopropylamine salt and potassium (1,350 and 1,512 g a.i. ha-1) used separately and together, with two deposition formats, in total area and directed jet, and two controls, one without any control method and the other weeded control. The association between the herbicides and the joint application of the three herbicides provided efficiency above 95% of control for volunteer soybean plants. The mixture of pyrithiobac-sodium and trifloxysulfuron-sodium (42.0 + 3.0 g a.i. ha-1), followed by sequential applications of glyphosate (1,512 g a.i. ha-1), regardless of the form of deposition of the herbicide, provided control above 95%, at 45 days after the first application, for the goosegrass (Eleusine indica) and viola-string (Ipomoea sp) plants. Symptoms of injury were observed in cotton plants, with greater intensity until 15 days after application (DAA), when pyrithiobac-sodium, trifloxysulfuron-sodium and glyphosate (36.4 + 2.25 + 1,350 g a.i. ha-1) were associated, reaching 35.5 % of the affected plants. Plant height was initially affected by the triple association between the herbicides pyrithiobac-sodium, trifloxysulfuron-sodium and glyphosate (36.4 + 2.25 + 1,350 g a.i. ha-1), however, at 90 DAA, all treatments provided higher plant height than the control without herbicide intervention, which was 95.3 cm. For boll weight, no difference was observed between the treatments, other than fiber yield, being lower for the treatments in which glyphosate was associated with pyrithiobac-sodium and trifloxysulfuron-sodium, providing 38.8 and 39.1%, respectively. Cotton yield was influenced by treatments where trifloxysulfuron-sodium was applied associated with glyphosate (2.62 + 1,350 g a.i. ha-1) and pythiobac-sodium, trifloxysulfuron-sodium and glyphosate (36.4 + 2.25 + 1,350 g a.i. ha-1), followed by glyphosate application at 43 DAE, but all treatments were superior to the control without herbicide application. Glyphosate applied alone or in association was essential for weed management in cotton production systems with RF technology.

Management of Glyphosate Isopropylamine-Resistant Goosegrass (Eleusine indica) Biotypes Through Pre- and Post-Emergence Herbicides

Management of Glyphosate Isopropylamine-Resistant Goosegrass (Eleusine indica) Biotypes Through Pre- and Post-Emergence Herbicides

Identification of Phytochemicals and Mineral Nutrients of Selected Malaysian Plant Extracts and its Effects on Seed Priming of Maize

Plants contain a variety of phytochemicals, which act as natural bioactive compounds to help plants enhance abiotic tolerance and promote growth. Therefore, plant extracts are considered to have great potential as environmentally friendly biostimulants in sustainable agriculture. This study aimed to identify the phytochemical compounds and quantify nutrients present in three plant extracts, namely Euphorbia hirta, Polygonum minus, and Eleusine indica, as well as to explore the effect on the growth of maize seedlings (Zea mays L.). The plant powder was extracted using methanol, followed by a solid-liquid extraction procedure. The phytocompounds were analyzed by liquid chromatography-mass spectrometry, while mineral nutrients were quantified using inductively coupled plasma. Five concentrations of plant extracts, i.e., 5, 15, 25, 50, and 100%, were designed to evaluate seed germination and priming. The result showed that 53, 45, and 39 phytocompounds were identified from E. hirta, P. minus, and E. indica, respectively, and classified into different chemical groups (such as flavonoids and amino acids) and rich nutrients (for example, N, P, and K). Besides, P. minus and E. hirta extracts with lower concentrations (5 and 15%) showed a positive effect on germination, shoot length and fresh weight, and the Highest concentration (100%) of E. hirta and E. indica extracts exhibited strong toxicity. This study emphasizes that weed extracts containing abundant secondary metabolites and nutrients can be used as natural biostimulants for maize seed priming.

Metabolic resistance mechanism to glufosinate in Eleusine indica

Eleusine indica is one of the most troublesome weeds in farmland worldwide, especially in Citrus Orchard of China. Glufosinate, as an efficient non-selective broad-spectrum herbicide, has been widely utilized for the control of E. indica in Citrus Orchard. The E. indica resistant population (R) was collected from a Citrus Orchard in Yichang City in Hubei province, China. Bioassay experiments showed that the R plants exhibited 3-fold resistance to glufosinate compared with the E. indica susceptible population (S). No known glutamine synthetase (GS) gene mutation associated with glufosinate resistance was found in R plants. And there was also no significant difference in GS activity between R and S plants. Those results indicated that the resistance to glufosinate in R did not involve target-site resistance. However, glutathione S-transferase (GST) inhibitor 4-chloro-7-nitrobenzoxadiazole (NBD-Cl) plus glufosinate gave a better control of R plants compared with glufosinate treatment alone. Moreover, both before and after glufosinate treatment, the GST activity in R plants was significantly higher than that in S plants. By RNA-seq, the expression of GSTU6 and GST4 up-regulated in R plants relative to S plants with or without glufosinate treatment. They were also significantly up-regulated expression in E. indica field resistant populations compared with S population. In summary, the study elucidated that R plants developed metabolic resistance to glufosinate involving GST. And GSTU6 and GST4 genes may play an important role in this glufosinate metabolic resistance. The research results provide a theoretical basis for a deeper understanding of resistance mechanism to glufosinate in E. indica.

Evaluation of Foliar Application of &lt;i&gt;Elusine indica&lt;/i&gt; Extract on Growth, Photosynthesis, and Osmoprotectant Contents in Maize under Drought Stress

To investigate the effects of foliar application of different concentrations of &lt;i&gt;Elusine indica&lt;/i&gt; extract (EIE) on growth, photosynthesis, and osmoprotectant contents in maize under drought stress. The weed powder was extracted using methanol, followed by a solid-liquid extraction procedure. Plants were sprayed with three different concentrations of EIE at 1, 3, and 5 g/L and morphological parameters, chlorophyll, relative water content (RWC), soluble sugar, proline, protein, glutathione (GSH), and malondialdehyde (MDA) contents were determined. The results showed that drought stress led to a decline in morphological characteristics, RWC and soluble sugar and increased proline, protein, GSH, and MDA contents. However, foliar application of EIE significantly improved plant height, fresh and dry weight, chlorophyll content, RWC, soluble sugar, and GSH, while the proline level was diminished compared to drought treatment. Soluble sugar showed a significant positive correlation with fresh and dry weight (&lt;i&gt;r&lt;/i&gt; = 0.742 and 0.783, &lt;i&gt;p&lt;/i&gt; &lt; 0.01) and a strong negative correlation with MDA (&lt;i&gt;r&lt;/i&gt; = -0.459, &lt;i&gt;p&lt;/i&gt; &lt; 0.05). Therefore, this result indicated that EIE can be used as an inexpensive and environmentally friendly biostimulant to help plants enhance tolerance to drought.

Multiple Horizontal Mini-chromosome Transfers Drive Genome Evolution of Clonal Blast Fungus Lineages.

Crop disease pandemics are often driven by asexually reproducing clonal lineages of plant pathogens that reproduce asexually. How these clonal pathogens continuously adapt to their hosts despite harboring limited genetic variation, and in absence of sexual recombination remains elusive. Here, we reveal multiple instances of horizontal chromosome transfer within pandemic clonal lineages of the blast fungus Magnaporthe (Syn. Pyricularia) oryzae. We identified a horizontally transferred 1.2Mb accessory mini-chromosome which is remarkably conserved between M. oryzae isolates from both the rice blast fungus lineage and the lineage infecting Indian goosegrass (Eleusine indica), a wild grass that often grows in the proximity of cultivated cereal crops. Furthermore, we show that this mini-chromosome was horizontally acquired by clonal rice blast isolates through at least nine distinct transfer events over the past three centuries. These findings establish horizontal mini-chromosome transfer as a mechanism facilitating genetic exchange among different host-associated blast fungus lineages. We propose that blast fungus populations infecting wild grasses act as genetic reservoirs that drive genome evolution of pandemic clonal lineages that afflict cereal crops.

Goosegrass Seedling Emergence and Growth in Bermudagrass Canopy and Divots

Goosegrass, Eleusine indica (L.) Gaertn., is a serious weed in bermudagrass, Cynodon spp. Rich., golf and sports turf. Reduction of canopy gaps such as divots might discourage goosegrass establishment because turf canopy reduces sunlight that could stimulate goosegrass seed germination. The objective was to compare goosegrass seedling emergence and growth under different conditions of bermudagrass canopy, including bare soil and divots of different ages, and the effect of fertilization rates. The first experiment compared surface treatments. Goosegrass seeds were planted monthly for 12 months in bare soil and divoted pots in a glasshouse. Initial goosegrass seedling emergence was large in the first month after planting, 23% in divots and 20% in bare soil, compared with only 9% emergence from canopy. Reduced emergence occurred from 2 to 8 months in canopy, divots, and bare soil. Cumulative goosegrass emergence was 44% in divots, 40% in bare soil, and 31% in canopy. In a second experiment, goosegrass seeds were planted in divots 0, 2, 4, 6, 8, and 10 weeks old. Divots were visibly closed within 4 to 6 weeks. By 9 weeks after seed planting, goosegrass seedling emergence was reduced 72% after planting in 10-week-old divots compared with fresh, 0-week divots. Goosegrass continued to emerge through all 63 weeks observed after seed planting. High fertilization rate, 123 g N/m2/year, from 10 to 63 weeks reduced cumulative late seedling emergence 34%, compared with half-rate fertilization, probably due to denser canopy under high fertilization. In a third experiment, goosegrass seedlings planted in closed bermudagrass canopy grew 90% less, in root and shoot fresh and dry mass, compared with seedlings planted in divots. Across all experiments, goosegrass emergence and growth were reduced by increased canopy.

Anti-diarrheal effects of ethanol leaf extract of Eleusine Indica in Castor Oil induced diarrhea using mice model

Ancient civilizations employed medicinal herbs to treat ailments. Medicinal herbs are essential for treating chronic disorders. Different medicinal plants can treat comparable ailments, depending on the country. In many rural communities in developing countries, particularly in Africa, therapeutic medicines and remedies derived from indigenous plants are almost invariably the only readily available and cost-effective alternatives to traditional diarrhea medicines. The study aims to evaluate the anti-diarrheal activity of the Eleusine indica ethanol extract in mice. The study used fresh Eleusine indica leaves. The extracts were administered at concentrations of 250, 500, and 1000 mg/kg for 28 days. On the 29th, the rats were induced with diarrhea, and blood samples were collected through the retro-orbital plexus before being sacrificed. The serum from the collected blood was used to run hematological and electrolyte tests. The liver and kidney function tests were analyzed using standard methods. The determination of antidiarrheal activity was done using the following models: Castor oil (CO) induced diarrhea, CO induced enteropooling activity, and CO induced gastrointestinal motility. The 80% ethanol extract produced significant (p&lt;0.001) antidiarrheal activity in all three models tested. The hematological, renal, hepatic, and electrolyte parameters of extract-treated mice were not significantly (p &gt; 0.05) different from those of the control group. There was no statistically significant difference (p &gt; 0.05) in the chloride, sodium, potassium, calcium, and bicarbonate levels of the extract-treated groups when compared to the control group. The findings of the studies demonstrated the antidiarrheal activities of Eleusine indica leaves, which could be a therapeutic option against diarrhea.

Cytochrome P450 CYP81A104 in Eleusine indica confers resistance to multiherbicide with different modes of action.

Developing herbicide-resistant (HR) crop cultivars is an efficient way to control weeds and minimize crop yield losses. However, widespread and long-term herbicide application has led to the evolution of resistant weeds. Here, we established a resistant (R) E. indica population, collected from imidazolinone-resistant rice cultivar fields. The R population evolved 4.5-fold resistance to imazamox. Acetolactate synthase (ALS) gene sequencing and ALS activity assays excluded the effect of target-site resistance in this population. P450 inhibitor malathion pretreatment significantly reversed resistance to imazamox. RNA sequencing showed that a P450 gene CYP81A104 was expressed higher in R versus susceptible (S) plants. Arabidopsis overexpressing CYP81A104 showed resistance to ALS inhibitors (imazamox, tribenuron-methyl, penoxsulam and flucarbazone-sodium), PSII inhibitor (bentazone), hydroxyphenyl pyruvate dioxygenase inhibitor (mesotrione) and auxin mimics (MCPA), which was generally consistent with the results presented in the R population. This study confirmed that the CYP81A104 gene endowed resistance to multiherbicides with different modes-of-action. Our findings provide an insight into the molecular characteristics of resistance and contribute to formulating an appropriate strategy for weed management in HR crops. © 2024 Society of Chemical Industry.

A Static Laser Weeding Device and System Based on Fiber Laser: Development, Experimentation, and Evaluation

To demonstrate the feasibility and improve the implementation of laser weeding, a static movable lift-adjustable closed fiber laser weeding device and system have been developed, followed by experiments and performance evaluations. Physical experiments were conducted on the energy required for laser cutting of weed stems, targeting four common larger weeds (Chenopodium album, Amaranthus spinosus, Setaria viridis, and Eleusine indica) in farmland and orchards. At the same irradiation distances, the energy required to cut the same type of large weed generally increases with increasing distances and stem diameters but decreases with increasing irradiation time. The variance of stems’ power density after irradiation was larger and the values were more dispersed for Chenopodium album and Setaria viridis weeds, and the values were relatively scattered, while the power density values of Amaranthus spinosus and Eleusine indica weeds were more concentrated. When the irradiation time was 10 s, the 3.892 W/mm2 laser was sufficient to eliminate weeds and plants with the irradiation distances of 2 m. The 2.47 W/mm2 laser was more effective, as it killed weeds within a distance of 1 m in less than 1 s. This work demonstrates the feasibility of the laser weeding device and system that can completely cut off the stems of large weeds, and this technology has the potential to promote sustainable agriculture.