Search Results (22)

Weeds compete with crops for resources, posing multiple negative impacts for agricultural production systems and triggering degradation of ecosystem services (e.g., alterations in the soil microbial community structure). Under the guidance of green plant protection, the development of efficient biocontrol strains with environmentally friendly characteristics has become a crucial research direction for sustainable agriculture. This study aimed to develop a fungal bioherbicide by isolating and purifying a pathogenic fungal strain (JZ-5) from infected redroot pigweed (Amaranthus retroflexus L.). The strain exhibited pathogenicity rates ranging from 23.46% to 86.25% against six weed species, with the most pronounced control efficacy observed against henbit deadnettle (Lamium amplexicaule L.), achieving a pathogenicity rate of 86.25%. Through comprehensive characterization of cultural features, morphological observations, and molecular biological identification, the strain was taxonomically classified as Fusarium oxysporum. Scanning electron microscopy revealed that seven days post-inoculation, F. oxysporum JZ-5 formed dense mycelial networks on the leaf surfaces of cluster mallow (Malva verticillata L.), causing severe tissue damage. Safety assessments demonstrated that the spore suspension (10⁴ spores/mL) had no adverse effects on three crops: hulless barley (Hordeum vulgare var. coeleste L.), wheat (Triticum aestivum L.), and potato (Solanum tuberosum L.). These findings suggest that F. oxysporum strain JZ-5 warrants further investigation as a potential bioherbicide for controlling three problematic weed species—Chenopodium album L. (common lambsquarters), Elsholtzia densa Benth. (dense-flowered elsholtzia), and Lamium amplexicaule L. (henbit deadnettle)—in cultivated fields of hulless barley (Hordeum vulgare var. coeleste L.), wheat (Triticum aestivum L.), and potato (Solanum tuberosum L.). This discovery provides valuable fungal resources for ecologically sustainable weed management strategies, contributing significantly to the advancement of sustainable agricultural practices. Full article

Biopesticides represent a safe and sustainable strategy for biological pest management, applicable to weed and fungal control. Biotechnological processing offers a promising approach to enhance the bioactivity of natural products for agricultural use. In this study, guishe juice, an agroindustrial residue derived from Agave lechuguilla, was bioprocessed via inoculation with Fusarium chlamydosporum, and its fungicidal and herbicidal potentials were evaluated. The fungal biotransformation led to the accumulation of phytochemicals, including flavonoids and polyphenols, significantly enhancing antioxidant activity to 76% and 96% as measured by DPPH and ABTS assays, respectively. The resulting bioprocessed guishe extract (BGE), particularly at 10% concentration (BGE-10), exhibited strong fungicidal activity, achieving 100% control of phytopathogenic fungi Fusarium spp. and Penicillium spp. Additionally, BGE-10 demonstrated a bioherbicidal effect, with a 77% weed control rate against Verbesina encelioides. These findings emphasize the potential of bioprocessed agave residues as dual-action bioagents, supporting the development of novel, eco-friendly agricultural solutions. Full article

Paramyrothecium eichhorniae TBRC10637 has been reported as a potential biocontrol agent of water hyacinth (Eichhornia crassipes) in Thailand. Despite its great potential, it remained unclear whether the strain may cause disease in other plant species, especially those sharing the same niche as water hyacinth. Here, we examined the strain for its specificity and pathogenicity on 55 plant species from 26 families ranging from crop plants to aquatic weeds. We showed that, except for water hyacinth, P. eichhorniae TBRC10637 did not cause leaf spot or leaf blight or on any of the tested plants. Scanning electron microscopy of spores inoculated on eight plant species, including economically important plants such as maize (Zea mays) and chilli (Capsicum annuum) at 0, 24, 48, and 72 h after inoculation, showed no spore germination, except on water hyacinth. Inoculation with spore-free culture washing led to blight symptoms on leaves of water hyacinth 72 h after inoculation, suggesting that enzymes and secondary metabolites may be involved in causing the blight symptoms. Our results confirmed high specificity of P. eichhorniae TBRC10637 towards water hyacinth, paving the way to control the spread of water hyacinth effectively. Full article

Recently, there has been growing interest by farmers and researchers in various agroecological approaches enhancing biodiversity and conservation including the use of natural herbicides derived from fungi to provide adequate weed control. This change is driven by growing concerns about herbicide resistance, environmental impacts and regulatory requirements. This review summarizes the results of various studies and highlights the efficacy and benefits of fungal bioherbicides in weed control. Fungi-based bioherbicides utilize the natural weed suppression capability of selected fungi to reduce weed density and competitiveness without completely eradicating the plants and such an approach is at the core of agroecology. Bioherbicides contribute to conservation by providing an environmentally friendly alternative to chemical herbicides. By reducing the reliance on synthetic chemicals, fungal bioherbicides help preserve soil health, water quality and protect non-target species, including beneficial organisms such as pollinators and soil microbes. They also promote biodiversity by selectively targeting specific weed species, leaving native plants and other organisms unharmed and favoring diversified weed flora without the dominance of a few species. Despite their promising potential, bioherbicides face several challenges, including delayed action, production difficulties and the potential toxicity of certain fungal toxins to mammals. This review highlights the growing adoption of fungal bioherbicides as an eco-friendly component of Integrated Weed Management (IWM). Further research is necessary to identify optimal fungal strains for controlling persistent weeds without putting at risk the overall biodiversity and to develop improved formulations for enhanced efficacy. Full article

Weeds cause significant agricultural losses worldwide, and herbicides have traditionally been the main solution to this problem. However, the extensive use of herbicides has led to multiple cases of weed resistance, which could generate an increase in the application concentration and consequently a higher persistence in the environment, hindering natural degradation processes. Consequently, more environmentally friendly alternatives, such as microbial bioherbicides, have been sought. Although these bioherbicides are promising, their efficacy remains a challenge, as evidenced by their limited commercial and industrial production. This article reviews the current status of microbial-based bioherbicides and highlights the potential of cell-free metabolites to improve their efficacy and commercial attractiveness. Stirred tank bioreactors are identified as the most widely used for production-scale submerged fermentation. In addition, the use of alternative carbon and nitrogen sources, such as industrial waste, supports the circular economy. Furthermore, this article discusses the optimization of downstream processes using bioprospecting and in silico technologies to identify target metabolites, which leads to more precise and efficient production strategies. Bacterial bioherbicides, particularly those derived from Pseudomonas and Xanthomonas, and fungal bioherbicides from genera such as Alternaria, Colletotrichum, Trichoderma and Phoma, show significant potential. Nevertheless, limitations such as their restricted range of action, their persistence in the environment, and regulatory issues restrict their commercial availability. The utilization of cell-free microbial metabolites is proposed as a promising solution due to their simpler handling and application. In addition, modern technologies, including encapsulation and integrated management with chemical herbicides, are investigated to enhance the efficacy and sustainability of bioherbicides. Full article

The effects of the bioherbicidal activity of the fungal phytopathogen, Albifimbria verrucaria (AV), formerly Myrothecium verrucaria, on glyphosate-resistant and –susceptible Conyza canadensis (horseweed) were examined in greenhouse and field studies. Spray applications of mycelial formulations of AV infected both glyphosate-resistant and -susceptible C. canadensis plants at various growth stages. Young plants in the rosette leaf stage of growth were controlled more efficaciously than were older plants that had bolted or that were in the inflorescence stage; nevertheless, severe injury and mortality also occurred in mature plants. The results indicate that this bioherbicidal fungus can infect and control C. canadensis, thereby demonstrating the potential of this fungus as a bioherbicidal agent against this troublesome weed, which has become resistant to various herbicides. Full article

In agriculture, weed management is a significant concern because their uncontrolled proliferation decreases soil quality for food crops. Allelopathy is a natural phenomenon in which the activity of allelochemical compounds inhibits the germination and growth of invasive plants as a defense mechanism. Among allelochemicals are polyphenols, which may affect genetic material or crucial enzyme activities for proper physiological function. Agroindustrial residues are a vast source of polyphenolic compounds with allelochemical activity. The bagasse of Agave Lechuguilla, known as guishe, is an abundant residue in México. The guishe has been characterized before by its polyphenolic content. Based on that, a fungal bioconversion process was developed to increase the availability of the allelochemicals in the guishe juice. First, guishe juice was obtained by mechanical pressed and characterized by spectrophotometric analysis. Results showed (g/L): 5.62 flavonoids, 0.64 of hydrolyzable polyphenols, 12.67 of reducing sugars, and 23.3 total sugars. The compounds detected by HPLC-ESI-MS were pterostilbene, hydroxycaffeic, caffeoyltartaric, and 4-O-glucoside coumaric acids, considered allelopathic. After the fungal bioprocess, (+)-gallocatechin and 3,7-Dimethyl quercetin were detected as additional compounds of interest. The flavonoid and hydrolyzable polyphenol content were modified to the highest accumulation of 1.57 and 14.9 g/L at 72 h, meaning a 2.45- and 2.22-fold increase. A bioprocess guishe juice (BGJ) was obtained at the compound accumulation peak of 72 h and evaluated in an allelopathic assay on model seeds (tomato and corn). Results show that BGJ inhibits up to 96.67% of corn seeds and up to 76.6% of tomato seeds compared to positive control. Full article

Weeds such as parasite plants are one of the most serious pests that farmers are forced to combat since the development of agriculture using different methods including mechanic and agronomy strategies. These pests have generated significant losses of agrarian and herding production, constituting a serious impediment for agricultural activities in reforestation practices and in important infrastructures. All these serious problems have induced the expansive and massive use of synthetic herbicides, which represents one of the main cause of environmental pollution, as well as serious risks for human and animal health. An alternative environmental friendly control method could be the use of bioherbicides based on suitably bioformulated natural products, of which the main ones are fungal phytotoxins. This review covers the literature from 1980 to the present (2022) and concerns fungal phytotoxins with potential herbicidal activity in order to obtain their efficacy as bioherbicides for practical application in agriculture. Furthermore, some bioherbicides based on microbial toxic metabolites are commercially available, and their application in field, mode of action and future perspectives are also discussed. Full article

(10S,11S)-(—)-epi-pyriculol is a phytotoxic metabolite produced by Pyricularia grisea, a fungus identified as a foliar pathogen on the invasive weed species buffelgrass (Cenchrus ciliaris) in North America. The effective control of buffelgrass has not yet been achieved, and there is a need to develop effective and green solutions. Herbicides based on natural products and the use of phytopathogenic organisms could provide the most suitable tools for the control of weeds such as buffelgrass. Thus, one of the most relevant points to study about potential suitable phytotoxins such as (10S,11S)-(—)-epi-pyriculol is its production on a large scale, either by isolation from fungal fermentations or by synthesis. For these purposes, rapid and sensitive methods for the quantification of (10S,11S)-(—)-epi-pyriculol in complex mixtures are required. In this study, a high-pressure liquid chromatography (HPLC) method for its quantification was developed and applied to organic extracts from twelve P. grisea isolates obtained from diseased buffelgrass leaves and grown in potato dextrose broth (PDB) liquid cultures. The analysis proved that the production of (10S,11S)-(—)-epi-pyriculol is fungal-isolate dependent and strongly correlated with phytotoxic activity, shown by the P. grisea organic extracts in a buffelgrass radicle elongation test. The HPLC method reported herein allowed us to select the best strain for the production of (10S,11S)-(—)-epi-pyriculol and could be useful for selecting the best cultural conditions for its mass production, providing a tool for the use of this promising metabolite as a new bioherbicide for the control of buffelgrass. Full article

Many plants are able to synthesize essential oils (EOs), which play key roles in defense against weeds, fungi and pests. This study aims to analyze the chemical composition and to highlight the antioxidant, antimicrobial and phytotoxic properties of the EOs from Eucalyptus falcata, E. sideroxylon and E. citriodora growing in Tunisia. EOs were analyzed by gas chromatography coupled to mass spectrometry (GC/MS) and their antioxidant properties were determined by total antioxidant capacity (TAC), DPPH and ABTS assays. The phytotoxic potential was assessed against weeds (Sinapis arvensis, Phalaris canariensis) and durum wheat crop (Triticum durum) and compared to chemical herbicide glyphosate. The antifungal activity was investigated in vitro against eight target fungal strains. All EOs displayed a specific richness in oxygenated monoterpenes (51.3–90%) and oxygenated sesquiterpenes (4.8–29.4%), and 1,8-cineole, citronellal, citronellol, trans-pinocarveol, globulol, spathulenol and citronellyl acetate were the main constituents. Eucalyptus EOs exhibited remarkable antioxidant activity and E. citriodora oil exhibited significant activity when compared with E. falcata and E. sideroxylon EOs. The phytotoxic potential of the tested oils had different efficacy on seed germination and the growth of seedlings and varied among tested herbs and their chemical composition variability. Their effectiveness was better than that of glyphosate. At the post-emergence stage, symptoms of chlorosis and necrosis were observed. Furthermore, a decrease in chlorophyll and relative water content, electrolyte leakage and high levels of MDA and proline were indicators of the oxidative effects of EOs and their effectiveness as bioherbicides. Moreover, all the EOs exhibited moderate fungitoxic properties against all the tested fungal strains. Therefore, according to the obtained results, Eucalyptus EOs could have potential application as natural pesticides. Full article

Araujia hortorum is a perennial vining plant species native to South America. It was introduced into many countries for ornamental and medicinal purposes as well as for its edible fruits, but it has become highly invasive, generating severe environmental problems. Biological control using bioherbicides and natural compounds is an interesting control option. The pathogenic fungus Ascochyta araujiae, isolated from infected leaves of A. hortorum, could be considered as a potential biocontrol agent. Its ability to produce bioactive metabolites was studied. The organic extract of the fungal culture filtrates showed interesting phytotoxic activities consisting of clearly visible necrotic symptoms (0.5–1 cm in diameter) in the punctured leaves. Thus, it was purified; this afforded three main metabolites. These were chemically and biologically characterised: one proved to be a new pentasubstituted dihydrofuro[3,2-b]furan-2(5H)-one, named araufuranone (1). The others were the already known fungal metabolites neovasinin and 2,4-dihydroxy-6-hydoxymethylbenzaldehyde (2 and 3). The structure of araufuranone was determined using spectroscopic methods (essentially 1D and 2D ¹H and ¹³C NMR and HR ESIMS spectra); its relative configuration was assigned by a NOESY spectrum. To the best of our knowledge, araufuranone is the first example of a naturally occurring compound showing that carbon skeleton. Assayed by a puncture, araufuranone proved to be weakly active on the leaves of Diplotaxis sp. and Sonchus sp.; the other two metabolites were even less toxic. Tested on cress, compounds 2 and 3 were able to partially inhibit rootlet elongation whereas araufuranone was almost inactive. Full article

Natural compounds have always represented an important source for new drugs. Although fungi represent one such viable source, to date, no fungal metabolite has been marketed as an anticancer drug. Based on our work with phytotoxins as potential chemical scaffolds and our recent findings involving three phytopathogenic fungi, i.e., Cochliobolus australiensis, Kalmusia variispora and Hymenoscyphus fraxineus, herein, we evaluate the in vitro anti-cancer activity of the metabolites of these fungi by MTT assays on three cancer cell models harboring various resistance levels to chemotherapeutic drugs. Radicinin, a phytotoxic dihydropyranopyran-4,5-dione produced by Cochliobolus australiensis, with great potential for the biocontrol of the invasive weed buffelgrass (Cenchrus ciliaris), showed significant anticancer activity in the micromolar range. Furthermore, a SAR study was carried out using radicinin, some natural analogues and hemisynthetic derivatives prepared by synthetic methods developed as part of work aimed at the potential application of these molecules as bioherbicides. This investigation opens new avenues for the design and synthesis of novel radicinin analogues as potential anticancer agents. Full article

Alternaria is a ubiquitous fungal genus in many ecosystems, consisting of species and strains that can be saprophytic, endophytic, or pathogenic to plants or animals, including humans. Alternaria species can produce a variety of secondary metabolites (SMs), especially low molecular weight toxins. Based on the characteristics of host plant susceptibility or resistance to the toxin, Alternaria phytotoxins are classified into host-selective toxins (HSTs) and non-host-selective toxins (NHSTs). These Alternaria toxins exhibit a variety of biological activities such as phytotoxic, cytotoxic, and antimicrobial properties. Generally, HSTs are toxic to host plants and can cause severe economic losses. Some NHSTs such as alternariol, altenariol methyl-ether, and altertoxins also show high cytotoxic and mutagenic activities in the exposed human or other vertebrate species. Thus, Alternaria toxins are meaningful for drug and pesticide development. For example, AAL-toxin, maculosin, tentoxin, and tenuazonic acid have potential to be developed as bioherbicides due to their excellent herbicidal activity. Like altersolanol A, bostrycin, and brefeldin A, they exhibit anticancer activity, and ATX V shows high activity to inhibit the HIV-1 virus. This review focuses on the classification, chemical structure, occurrence, bioactivity, and biosynthesis of the major Alternaria phytotoxins, including 30 HSTs and 50 NHSTs discovered to date. Full article

Certain plant pathogens have demonstrated potential for use as bioherbicides for weed control, and numerous studies have been published on this subject for several decades. One of the early examples of an important fungal bioherbicide is Alternaria cassiae, isolated from the weed sicklepod (Senna obtusifolia). To gain further insight into biochemical interactions of this fungus and its host weed, we examined the effects of this bioherbicide on various enzymes associated with plant defense. Young sicklepod seedlings were challenged with A. cassiae spore inoculum and enzyme activities associated with plant defense (peroxidase, proteolytic, and pectinolytic) were assayed periodically over a 96-h time course on plants grown in continuous darkness or continuous light. Peroxidase activity increased with time in untreated control seedlings in both light and dark, but the effect was greater in the light. In A. cassiae-treated plants, peroxidase was elevated above that in control tissue at all sample times resulting in a 1.5 -fold increase above control in light-grown tissue and a 2- to 3-fold increase in dark-grown tissue over 48–96 h. Differences in leucine aminopeptidase activity in control versus A. cassiae-treated tissues were not significant until 48–96 h, when activity was inhibited in fungus-treated tissues by about 32% in light-grown tissue and 27% in dark-grown tissue after 96 h. Proteolytic activity on benzoyl-arginine-p-nitroanilide was not significantly different in treated versus control tissue in either light or dark over the time course. Pectinase activity increased in treated tissues at all time points as early as 16 h after spore application in light- or dark-grown plants. The greatest increases were 1.5-fold above control levels in light-grown plants (40–64 h) and 2-fold in plants grown in darkness (72–96 h). Data suggests that peroxidase may be involved as defense mechanism of sicklepod when challenged by A. cassia and that this mechanism is operative in young seedlings under both light and dark growth conditions. Differential proteolytic activity responses on these two substrates suggests the presence of two different enzymes. Increased pectinase activity during pathogenesis suggests that A. cassiae-sicklepod interaction results in an infectivity mechanism to degrade pectic polymers important to sicklepod cell wall integrity. These studies provide important information on some biochemical interactions that may be useful for improvements to biological weed control programs utilizing plant pathogens. Such information may also be useful in genetic selection and manipulation of pathogens for weed control. Full article

The fungal genus Myrothecium was once polyphyletic but a recent reconsideration of the family Stachybotryaceae spilt it into several genera. The ex-neotype specimen of the species Myrothecium verrucaria is now recognized as Albifimbria verrucaria. The well-studied plant pathogen and candidate bioherbicide CABI-IMI 368023, previously identified as M. verrucaria, was analyzed morphologically and genetically and found to be most consistently aligned with the other representatives of A. verrucaria. Full article