Search Results (35)

The possible origin of four cultivated species of the genus Avena of different ploidy and different subgenome composition (A. strigosa, A. abyssinica, A. byzantina, and A. sativa) from possible wild species was investigated. The region of the internal transcribed spacer ITS1 and the 5.8S rRNA gene in the cultivated species was studied with next-generation sequencing (NGS), and the patterns of occurrence and distribution of the ribotypes were compared among them and with those of the wild species. According to these data diploid, A. strigosa is more closely related to the diploid A. hirtula than to polyploid oats, and it could have evolved independently of polyploid cultivated species. The tetraploid Avena abyssinica could be a cultivated derivative of A. vaviloviana. Two hexaploid cultivated species, A. byzantina and A. sativa, could have a different origin; A. sativa could be the cultivated form of A. fatua, whereas A. byzantina could originate independently. It was found that the oat species with the A and C subgenomes, even with strong morphological and karyological differences, could intercross and pass the further stages of introgression producing a new stable combination of genomes. Our data show that almost all species of Avena could form an introgressive interspecies complex. Full article

The information on the involvement of hormones in the release of dormancy in grass caryopses is still insufficient. The main aim of the present study was to deepen our understanding of the mechanism dormancy release in Avena fatua L. caryopses by after-ripening in relation to abscisic acid (ABA) and gibberellins (GAs). The after-ripening of florets during dry storage resulted in dormancy removal in caryopses, allowing their germination at 20 to 30 °C. Sensitivity to ABA and paclobutrazol (PAC), a GAs biosynthesis inhibitor, decreased as the after-ripening period was extended. After-ripening increased the ABA content in the embryos of dry caryopses and decreased the total content of bioactive GAs, except for GA₁, the content of which increased. Accordingly, the ABA/GAs ratio was increased, and the ABA/GA₁ ratio was lowered due to after-ripening. After-ripening led to a decrease in the ABA content and increased the bioactive GAs contents, including GA₁ and GA₆, regarded as the most important for germination, in the embryos within 18 h of caryopses germination. The results obtained indicate that the embryos of dormant caryopses contained sufficient levels of bioactive GA₁ and GA₆ at early stages of germination, but their germination was prevented due to having too high an ABA concentration. It seems that the agents most important in dormancy removal through after-ripening include a reduction in the ABA content and sensitivity, as well as an increase in the bioactive GAs, particularly GA₁ and GA₆, in the embryos of germinating caryopses, which brings about a reduction in the ABA/GAs, ABA/GA₁, and ABA/GA₆ ratios, thus enabling germination. Full article

In screening for biocontrol strains with broad-spectrum and efficient herbicidal activity, strain GD-011 isolated from naturally susceptible M. sativa (Medicago sativa L.) roots was selected as a promising candidate. The control effects of strain GD-011 on nine weeds of Qinghai farmland were evaluated in vitro and in vivo, and its safety to five local crops was tested. The in vivo spray inoculation test showed that strain GD-011 had a strong pathogenic effect on the weeds M. verticillata (Malva verticillata L.), E. densa (Elsholtzia densa Benth), and A. fatua (Avena fatua L.), with incidence rates of more than 80.87% and fresh weight control effects of more than 71.8%. Crop safety tests showed that the B. napus (Brassica napus L.) crop is moderately susceptible to strain GD-011, with slight reactions in H. vulgare (Hordeum vulgare L.), but strain GD-011 is safe for T. aestivum (Triticum aestivum L.), P. sativum (Pisum sativum L.), and V. faba (Vicia faba L.) Observations on the morphological characteristics combined with a sequence analysis of the ribose rDNA internal transcribed spacer (rDNA ITS), the Elongation factor (EF-1α) gene, and the antigen-related protein gene (Alt a1) identified strain GD-011 as Alternaria gaisen. Scanning electron microscopy observations showed that the mycelia of strain GD-011 invaded the leaf tissue through the stomata on the surface, with the formation of a parasitic mycelium network on the surface of the tissue, the metabolism of E. densa leaf tissues was disturbed, and leaf tissues appeared to be broken. From the perspective of its herbicidal potential, the metabolites of strain GD-011 have good control effects on most weeds and are relatively safe for crops. Full article

Mythimna separata (Walker), a significant migratory pest in many Asian countries, can cause severe damage to wheat crops. Understanding whether wild oat can serve as an alternate host is important for informing predictive models of M. separata infestation levels in wheat fields and can improve pest and weed management strategies. We first conducted both choice and no-choice experiments and found that M. separata readily laid eggs on both wheat and wild oat, with no significant oviposition preference. However, newly hatched larvae exhibited a strong preference for wheat, with 53.34% more larvae feeding on wheat compared to wild oat. Development time from egg to adult emergence was significantly shorter in M. separata fed on wheat than on wild oat, although the durations of the larval and pupal stages varied depending on the host plant. Despite these differences in development time, host plants did not significantly affect larval survival, pupal weight, fecundity, and adult longevity. The mean number of eggs laid by females that fed on wheat and wild oat were 1202.12 and 1270.54 eggs/female, and larval survival rates were 81% and 84%, respectively. Our findings suggest that wild oat can serve as a suitable host for M. separata and may act as a refuge when wheat fields are treated with insecticides. The high larval preference for wheat over wild oat indicates that M. separata on wild oat may easily disperse to wheat, complicating pest control and highlighting the need to include wild oat in pest management strategies. Full article

The phytotreatment technique, which has never been used to treat emerging compounds, is used in this work to measure the phytoextraction of octocrylene (OC) in three concentrations (200, 400, and 600 μg/L of OC) by Salvinia biloba Raddi. The species proved to be a phytoextractor by accumulating OC in floating leaves at concentrations of 1,500,000 μg/kg in treatment 200 and 1,050,000 in 600 μg/L of OC. Chlorophyll synthesis was affected at all OC concentrations, especially 400 μg/L, with a chlorophyll a/b ratio of less than 1. Enzymatic activity responded to the contaminant: CAT and APX are inhibited in the submerged portions after 48 h, staying below 2.0E⁻⁶ μmol/min/μg of protein. GPOX was totally inhibited during the experiment, and SOD remains active at 200 and 600 μg/L. The cytogenotoxic effects of OC to confirm phytoextraction were evaluated by globally regulated tests with Allium cepa bulbs and germinal bulbs in Lactuca sativa and Avena fatua every 48 h. These tests showed that after 72 h of phytoextraction, the medium was no longer cytogenotoxic and the seeds germinated above 30%, confirming the phytoextractor capacity of S. biloba. Thus, we can affirm that S. biloba can be used in the phytotreatment of aquatic environments contaminated with OC. Full article

Biological control is a scientific management method used in modern agricultural production, and microbially derived biopesticides are one effective method with which to control weeds in agricultural fields. In order to determine the key genes for weed control by Trichoderma polysporum, transcriptome sequencing was carried out by high-throughput sequencing technology, and the strains of T. polysporum HZ-31 infesting Avena fatua L. at 24, 48, and 72 h were used as the experimental group, with 0 h as the control group. A total of 690,713,176 clean reads were obtained, and the sequencing results for each experimental group and the control group (0 h) were analyzed. In total, 3464 differentially expressed genes were found after 24 h of infection with the pathogen, including 1283 down-regulated genes and 2181 up-regulated genes. After 48 h of infection, the number of differentially expressed genes was 3885, of which 2242 were up-regulated and 1643 were down-regulated. The number of differentially expressed genes after 72 h of infection was the highest among all the groups, with 4594 differentially expressed genes, of which 2648 were up-regulated and 1946 were down-regulated. The up-regulated genes were analyzed by GO and KEGG, and the results showed that the up-regulated differentially expressed genes were mainly enriched in the biosynthesis of phenylalanine, tyrosine, and tryptophan; the degradation of aromatic compounds; methane metabolism; and other pathways. Among them, the PHA2, GDH, ADH2, and AROF genes were significantly enriched in the above-mentioned pathways, so they were hypothesized to play an important role in the synthesis of the herbicidally active substances of T. polysporum HZ-31. The results of this study can provide a theoretical basis for further studies on the pathogenicity of T. polysporum to A. fatua L., and accelerate the development and utilization of new and efficient bioherbicides. Full article

Cinmethylin is a potential pre-emergence herbicide that could be used to control grass weeds in winter cereals. To determine the herbicidal activity of cinmethylin against common gramineous weeds in wheat fields in China and its level of safety on wheat, we conducted the following experiments: (i) assessing the efficacy of cinmethylin against 11 grass weeds and (ii) determining its safety against 19 wheat varieties. The results showed that cinmethylin had good herbicidal efficacy against annual bluegrass (Poa annua L.), shortawn foxtail (Alopecurus aequalis Sobol.), slender meadow foxtail (Alopecurus myosuroides Huds.), Japanese foxtail (Alopecurus japonicus Steud.), Italian ryegrass (Lolium multiflorum Lam.), British timothy (Phleum paniculatum Huds.), Asia Minor bluegrass (Polypogon fugax Nees ex Steud.), Helictotrichon tibeticum (Roshev.) Holub., and wild oat (Avena fatua L.), with a GR₅₀ (the herbicide dose resulting in 50% growth inhibition) value of 4.50–99.21 g a.i. ha⁻¹ in plant height and 1.43–70.34 g a.i. ha⁻¹ in fresh weight. However, cinmethylin cannot control Japanese brome (Bromus japonicus L.) or Tausch’s goatgrass (Aegilops tauschii Coss.) at a dose of 200 g a.i. ha⁻¹. Different wheat varieties varied in their phytotoxicity to cinmethylin. Overall, there is a phytotoxicity risk when using cinmethylin on wheat, mainly to wheat roots, with a reduction in root length of 40.81–64.09% at a dose of 400 g a.i. ha⁻¹. These findings indicate that the pre-emergence herbicide cinmethylin provides good efficacy against most grass weeds and may possess potential for weed management in wheat fields. However, attention should be given to the application dosage and the sensitivity of wheat varieties when using cinmethylin in wheat fields. Full article

Using plant extracts as eco-friendly reducing and stabilizing agents for the synthesis of nanoparticles has gained significant attention in recent years. The current study explores the green synthesis of silver nanoparticles (AgNPs) using the Avena fatua extract and evaluates their antifungal activity against Fusarium oxysporum f.sp. lycopersici (Fol), a fungal plant pathogen. A green and sustainable approach was adopted to synthesize silver nanoparticles before these nanoparticles were employed for anti-fungal activity. The primary indication that AgNPs had formed was performed using UV-vis spectroscopy, where a strong peak at 425 nm indicated the effective formation of these nanoparticles. The indication of important functional groups acting as reducing and stabilizing agents was conducted using the FTIR study. Additionally, morphological studies were executed via SEM and AFM, which assisted with more effectively analyzing AgNPs. Crystalline behavior and size were estimated using powder XRD, and it was found that AgNPs were highly crystalline, and their size ranged from 5 to 25 nm. Synthesized AgNPs exhibited significant antifungal activity against Fol at a concentration of 40 ppm. Furthermore, the inhibitory index confirmed a positive correlation between increasing AgNPs concentration and exposure duration. This study suggests that the combined phytochemical mycotoxic effect of the plant extract and the smaller size of synthesized AgNPs were responsible for the highest penetrating power to inhibit Fol growth. Moreover, this study highlights the potential of using plant extracts as reducing and capping agents for the green synthesis of AgNPs with antifungal properties. The study concludes that A. fatua extract can synthesize antifungal AgNPs as a sustainable approach with robust antifungal efficacy against Fol, underscoring their promising potential for integration into plant protection strategies. Full article

This study developed an unattended electric weeder (UEW) to control floor weeds in an orchard greenhouse. The UEW was a motor-driven dolly equipped with a spark exposer. The spark exposer was constructed by applying an alternating voltage (10 kV) to a conductor net (expanded metal net). The charged conductor net (C-CN) discharged into the surrounding space. Wild oat and white clover were used as test weed species. Weed seedlings growing on the floor were grounded by the biological conductor and were subjected to a spark from the C-CN when they reached the discharge space. The spark-exposed seedlings were singed and shrunk instantaneously. In the present experiment, the UEW was remotely controlled to move on the soil-cover metal nets, which were laid on the floor to make a flat surface, in a stop-and-go manner, and to eject a spark to the weed seedlings that emerged from the floor. All of the mono- and dicotyledonous weed seedlings, which had been artificially sown on the floor, were completely eradicated using this method. Thus, this study provides an experimental basis for developing an unattended technique for controlling floor weeds in an orchard greenhouse. Full article

In this article, we analyzed the origin of wild polyploid oats (Avena L., Poaceae) using the region 18S rDNA (partially)–ITS1–5.8S rDNA obtained via NGS. There are six tetraploid (2n = 28) and four hexaploid (2n = 42) wild species differing by specific genome combinations: A. barbata, A. vaviloviana (AB), A. agadiriana (AB or BB), A. magna, A. murphyi, A. insularis (AC or CD), A. ludoviciana, A. sterilis, A. fatua, and A. occidentalis (ACD). We compared the pool of marker sequences of polyploid oats with those of their putative diploid ancestors: A. atlantica (As-genome), A. hirtula (As), A. canariensis (Ac), A. ventricosa (Cv), and A. clauda (paleopolyploid with Cp and A-related rDNA). We found 15 major ribotypes (more than 1000 reads per rDNA pool) in polyploid oats. Comparing them, we found that the AB-tetraploid oats possibly inherited their A-genome ribotypes from A. atlantica (As1-ribotype), whereas their B-genome ribotype is specific and can be a derivative of the A-genome family. Our data do not support the hypothesis of the CD-genome set in A. magna, A. murphyi, and A. insularis: they have an AC-genome ribotype constitution instead. The C-genome-related sequences could have been obtained from A. ventricosa. Hexaploids show a different ribotype pattern than tetraploids; the main ribotypes of A. fatua, A. ludoviciana, and A. sterilis probably belong to the D-group and are also shared with one of the major ribotypes of A. clauda. Full article

In recent decades, cereal agriculture across main producing areas in Spain has progressively adopted direct sowing, associated with an increased use of herbicides in pre-sowing. Weedy species from genus Avena have been observed after the application of glyphosate in wheat. Here, Avena fatua (two accessions), Avena byzantina and Avena sterilis subsp. sterilis, one accession each, were taxonomically characterized by a biometric study. Dose-response trials confirmed that one A. fatua accession evolved to resistance, because it was four times more resistant (R) than the others, ascribed as susceptible (S). In addition, based on LD₅₀, A. byzantina and A. sterilis had low susceptibility to glyphosate, with 604 and 458 g ae ha⁻¹. Shikimic acid accumulation was able to discriminate between high susceptible (A. fatua (S)), low susceptible (A. byzantina and A. sterilis), and low resistant (A. fatua (R)) populations. On the other hand, the study revealed that A. fatua (R), A. byzantina and A. sterilis had low foliar uptake and decreased movement of glyphosate. In addition, the metabolism study showed less metabolite accumulation in A. byzantina and A. fatua (S). However, at 96 h after glyphosate application, A. fatua (R) and A. sterilis were able to convert more than 30% of glyphosate to aminomethylphosphonic acid (AMPA) and sarcosine. Enzyme basal activity and I₅₀ values predicted high affinity between the herbicide and the target enzyme for all accessions, thus indicating that a target-site (TS) mechanism is probably not involved in the differences in glyphosate susceptibility. In closing, non-target site (NTS) mechanisms could participate both in A. fatua R to glyphosate, and low susceptibility in A. byzantina and A. sterilis from Spain. Full article

Fungi colonizing the surface and endosphere of two widespread Poaceae weed species, Avena fatua and Echinochloa crus-galli, were isolated to compare the taxonomic composition between the plant species, location, and year of the seed collection. The seed-degrading potential of Fusarium isolated from the seeds was tested by inoculating seeds of E. crus-galli with spore suspension. Molecular identification of epiphytic and endophytic fungal genera was performed by sequencing the ITS region of rDNA. Endophytes comprised of significantly lower fungal richness compared to epiphytes. A significant taxonomic overlap was observed between the endosphere and seed surface. The most abundant genera were Alternaria, Fusarium, Cladosporium, and Sarocladium. Analysis of similarities and hierarchical clustering showed that microbial communities were more dissimilar between the two plant species than between the years. Fusarium isolates with a high potential to infect and degrade E. crus-galli seeds in laboratory conditions belong to F. sporotrichioides and F. culmorum. Full article

Natural products are one of the resources for discovering novel pesticide leads. Here, by molecular hybridization between the natural enamino diketone skeleton and the reported herbicide lead compound I, a series of 3-(1-aminoethylidene)-6-methyl-2H-pyran-2,4(3H)-dione derivatives (APD) were rationally designed, synthesized and tested for herbicidal activity in a greenhouse. The bioassay results showed that most of the target compounds possessed good herbicidal activity under pre-emergence conditions, of which the analog APD-II-15 displayed good pre-emergent herbicidal activity against Abutilon theophrasti Medicus, Amaranthus retroflexus L., Echinochloa crus-galli, Eragrostis curvula (Schrad.) Nees, Avena fatua L., Cyperus difformis L., Chenopodium album L., Ixeris denticulata, Plantago asiatica L., Capsella bursa-pastoris (Linn.) Medic and Flaveria bidentis (L.) Kuntze with > 60% inhibition even at a dosage of 187.5 g ha⁻¹, and displayed good crop safety for wheat, soybean, millet and sorghum at a dosage of 375 g ha⁻¹. The preliminary study of the molecular mode of action by RNA sequencing suggested that a growth inhibition of weeds by APD-II-15 might result from the disruptions of carbon metabolism and formation of a cytoskeleton. The present work indicated that APD-II-15 might be used as a novel herbicidal lead compound for further optimization. Full article

Wild oat is a nuisance monocot weed mainly in cereal canopies. The increasing problem of herbicide resistance and the implementation of integrated pest management includes the use of seed meals from species with allelopathic potential. This study aimed to assess the efficacy of seed meals as an environmentally friendly alternative for the control of herbicide-susceptible (S) and -resistant (R) wild oat biotypes. A pot experiment was carried out under greenhouse conditions at the Swojczyce Research and Training Station in Wrocław (Poland) to determine the impact of seed meals from Fagopyrum esculentum, Lupinus luteus, Ornithopus sativus, Phacelia tanacetifolia, Raphanus sativus var. oleiformis and Sinapis alba at two concentrations—1 and 3%. The lowest percentage of seedling emergence was recorded after the application of S. alba seed meal. Seed meals from S. alba reduced the emergence of both S and R biotypes by approximately 82 and 61 percentage points, respectively, and limited the initial growth of both biotypes. F. esculentum, O. sativus and R. sativus seed meals generally did not decrease the number of seedlings. Almost all the seed meals inhibited the growth of the aboveground parts of the susceptible biotype of wild oat to a greater extent than the herbicide treatment. Full article

Weeds are a major impediment to crop and pasture production and profitability in Australian farming systems, and knowledge of their occurrence is vital in devising weed management solutions. This study examined the relationships between weed and crop species from observations made during surveys of randomly selected fields in grain and/or pasture production. Between 2013 and 2017, 996 fields across New South Wales (NSW) were surveyed to record the occurrence and density of weed species. Annual ryegrass (Lolium rigidum) (69% of fields), wild oats (Avena spp.) (60%), and sowthistle (Sonchus oleraceus) (34%) were the most common species identified, with a total of 65 weed species recorded to be occurring in NSW cropping fields. Densities of occurring weeds were low, at one plant per square metre or less. Multiple species of wild oats were recorded, with their occurrence varying between survey regions; for example, Avena sterilis subsp. ludoviciana was more prevalent in the north and Avena fatua in the south. Differences in weed species occurrence were noted between this survey and those previously conducted in NSW, with marked increases in annual ryegrass and sowthistle, and this is attributed to the change in crop production practices between survey periods. The study of variable distribution patterns of weed species across cropping systems allows for informed decision-making regarding weed management research and development planning. Full article