Soybean Charcoal Rot Research Articles

Effect of Drought Stress During Seed Development on Charcoal Rot and Yield of Soybean.

The primary controls for charcoal rot in soybean, caused by the fungal pathogen Macrophomina phaseolina, are to avoid drought stress and to plant a moderately resistant cultivar. The effects of irrigation and cultivar were determined in 2011 and 2013 at the Lon Mann Cotton Research Station, Marianna, AR. Four soybean cultivars (Hutcheson, Osage, Ozark, and R01581F) were planted in plots with or without added M. phaseolina inoculum and subjected to three furrow irrigation regimes: full-season irrigation (Full), irrigation terminated at R5 (CutR5), and nonirrigated (NonIrr). Normalized difference vegetation index (NDVI) was measured at R3 and R6. At harvest, plants and yields were collected. Roots and stems were split and the extent of visible colonization by M. phaseolina microsclerotia was assessed in the roots with a 1 to 5 scale (RSS) and the percent plant height stem discoloration measured. Precipitation in September and October was 54 and 65% below the 30-year average in 2011 and 2013, respectively. The CutR5 irrigation treatment resulted in one less irrigation than Full each year, but CutR5 NDVIs at R6 and yields were significantly lower than those with Full and not significantly different from those of NonIrr. The CutR5 RSS ratings were greater than either Full or NonIrr. Plant colonization by M. phaseolina was negatively correlated to yield in 2011 but not in 2013. No premature plant death caused by charcoal rot was observed in either year. These results indicated that late-season drought stress may be more important to charcoal rot development than drought stress throughout the season, but other factors are needed to trigger early plant death and subsequent yield losses observed in grower fields.

Biological control of soybean charcoal rot by native Trichoderma koningiopsis in Tucumán, Argentina

Macrophomina phaseolina (Tassi) Goid. (Mp) is the causal agent of charcoal rot in soybean, an economically serious and potentially destructive disease. Chemical control sometimes has limited effects on disease severity and may pose a threat to the environment, so the use of Trichoderma as a biological product could be a feasible alternative for charcoal rot management. The objective of this research was to isolate and characterize native Trichoderma spp. from northwestern Argentina and study their antagonistic effect against Mp in soybean. Isolations were performed from soil samples followed by cultural and microbiological characterization of the Trichoderma spp. isolates collected. Then, the antagonist effect against Mp was studied in vitro, under greenhouse conditions, and finally under field conditions with pathogen artificial inoculations during two soybean crop seasons (2020 and 2021). The results demonstrated that isolate Tr009 had a biocontrol effect against Mp in soybean. This control was evidenced in vitro and under controlled and field conditions with high emergency of plants compared to the Mp inoculated control. Under field conditions, treatments that included Trichoderma presented lower disease severity, colony-forming unit index and disease severity index values than the pathogen inoculated control. Moreover, Tr009 improved weight and length of soybean plants under greenhouse conditions. Isolate Tr009 was identified as Trichoderma koningiopsis by molecular methods. These results indicate that this biological tool can be used against Mp and thus favor a sustainable management of soybean charcoal rot.

The Problem of Charcoal Rot in Soybean, its Implications, and Approaches for Developing Resistant Varieties

Soybean is an annual legume with edible seeds. The soybean’s charcoal rot is one of the serious challenges faced in its cultivation regions, which brings severe production and economic losses. charcoal rot is the result of infection by the soil-borne fungus Macrophomina phaseolina. Though several researchers have made efforts to deal with soybean’s charcoal rot challenge, but at present, there are no soybean varieties in the market that are resistant to charcoal rot. The pathogen is thought to infect plants in their roots from contaminated soil, using unknown toxin-mediated processes. Conventional integrated approaches for managing charcoal rot in soybeans have been implemented in the field, but their efficacy is limited. So, developing soybean durable resistant varieties against M.phaseolina is the only solution to rescuing this crop. The potential approach is identifying new genetic sources and quantitative trait loci (QTLs) associated with resistance to charcoal rot in the resistant soybean population and conducting genome-wide association studies to increase understanding of underlying resistance mechanisms. The discovery of the genetic markers associated with resistance will contribute to charcoal rot resistance genotype selection for breeding programs in the future.

Model-Based Community Analyses Identify Fungal Endophytes that May Modulate Symptom Development of Charcoal Rot Disease in Soybean

Charcoal rot disease of soybean is a major threat to soybean harvests in the United States. This disease, caused by the fungal pathogen Macrophomina phaseolina (MP), cannot be economically treated in agronomic field conditions, and breeding of resistant cultivars has been largely unsuccessful due to multiple gene resistance. For difficult-to-treat phytopathogens, nascent research has emphasized the potential utility of endophyte modulation of disease symptoms. Most research into biocontrol of MP in soybeans has focused on in vitro or limited greenhouse/pot experiments, which may not emulate field conditions. Here, using a paired framework of diseased and asymptomatic soybeans exposed to MP in a production field setting, coupled with model-based community analyses, we identify several fungal endophytic taxa that apparently modulate disease pathogenicity. We use a multilevel analytical framework to provide evidence of taxa that respond to the disease state by querying plants across years and plant compartments. Additional work is needed to test the mechanisms by which these identified taxa may modulate MP, but this work provides the strongest evidence to date that endophytes may modulate charcoal rot disease levels in production field conditions. We posit that breeding for improved colonization of disease-modulating endophytes is a promising option to manage charcoal rot in soybean. [Formula: see text] Copyright © 2024 The Author(s). This is an open access article distributed under the CC BY-NC-ND 4.0 International license .

Glyphosate combined with manganese phosphite reduces charcoal rot severity in soybean

Macrophomina phaseolina is the causal agent of charcoal rot in soybean and causes yield losses. Glyphosate herbicide can immobilize micronutrients like manganese and iron, thus heightening plant susceptibility to diseases. Phosphites (Phi) are elicitors which also act as fungicides and can potentially contribute nutrients. The effects of glyphosate (Gly), manganese phosphite (MnPhi), and their combination (Gly + MnPhi) on the in vitro growth of M. phaseolina mycelium and the severity of charcoal rot in glyphosate-resistant soybean plants. Results showed that MnPhi had the lowest mean IC50 at 288 ppm, while the Gly + MnPhi had the highest mean IC50 at 406 ppm. Gly + MnPhi showed a 31% reduction in charcoal rot severity in the roots compared to the untreated control. Since both active ingredients in Gly + MnPhi can translocate to the roots, this treatment holds potential in controlling charcoal root disease.

Establishment of Pathogenicity Test Method for Macrophomina phaseolina Causing Soybean Charcoal Rot

The establishment of a laboratory assay and a greenhouse assay was conducted for evaluating the pathogenicity of Macrophomina phaseolina causing soybean charcoal rot established. In the laboratory assay, microsclerotia and hyphae were used as inoculum. In the laboratory assays using microsclerotia as an inoculum, disease incidences of M. phaseolina NSW17-108 and HSM17-034 were higher at 35°C than 25°C. Of the two isolates NSW17-108 and HSM17-034, the disease incidence of HSM17-034 isolated from diseased sesame is higher than that of NSW17-108 isolated from diseased soybean. When the mycelia of M. phaseolina were used as an inoculum, the disease incidence of NSW17-108 and HSM17-034 at 35°C exceeded 80% even after only 5 days of inoculation. Even at 25°C, furthermore, that of HSM17-034 exceeded 80% 5 days later. In the pathogenicity assays at a greenhouse, toothpicks where microsclerotia were produced or microsclerotia harvested from potato dextrose agar medium were used as an inoculum. In all greenhouse assays, M. phaseolina NSW17-108 and HSM17-034 showed 40–60% of disease incidences 35–65 days after inoculation with the pathogen, depending on the inoculation method. Between the two isolates, the pathogenicity of HSM17-034 was stronger than that of NSW17-108, and this result was consistent with laboratory assay results. Since the laboratory and greenhouse test methods tested in this study have different advantages and disadvantages depending on each test method, it is thought that the test method that can meet the purpose of the study should be selected and used.

Extracción de proteínas secretadas por el fitopatógeno Macrophomina phaseolina: Selección de un método eficiente que incluye estímulo con tejido de su hospedero

The globally distributed necrotrophic fungus Macrophomina phaseolina is the causal agent of economically important crop diseases such as soybean charcoal rot. This fungus secretes a wide variety of proteins and metabolites that allow it to invade the plant and initiate the infection process. The role of fungi secreted proteins with hydrolytic activity in the infection process has been extensively studied; proteins without enzymatic activity could also play an important role in this process. The analysis of total proteins would allow to broaden the knowledge about this pathogen and establish more efficient strategies for its control. The objective of the present work was to evaluate three methods for the extraction of proteins secreted by M. phaseolina. The fungus was grown in potato dextrose broth (PDB) and Czapek-Dox (CZP) with and without soybean leaf supplementation. Proteins were extracted from the lyophilized filtrate of PDB medium using three extraction methods and analyzed by SDS-PAGE. The protein precipitation with trichloroacetic acid in acetone was selected because it showed a better resolution of the protein profile. The filtrate of M. phaseolina grown in PDB supplemented with soybean (MpPDBs) presented the highest yield of protein extraction of secreted proteins among all conditions evaluated. The protein profiles of PDB medium with and without supplementation showed seven differential bands, one of the specific, detected in MpPDBs. These results constitute a basis for studies on the implication of proteins secreted by the fungus in the infection process.

Efficacy of Achromobacter Spp. Isolated from Rhizosphere of Soybean Against Macrophomina phaseolina

Soybean is an important oil seed crop produced in India, Madhya Pradesh is the largest soybean producing state. Charcoal rot caused by Macrophomina phaseolina is a major threat to soybean production leading to 30-50% yield loss. Biological control is an effective measure for management of this disease. Soil rhizosphere is a rich source of beneficial microbes able to suppress plant pathogens and promote plant growth. Present study aimed at isolating and characterizing indigenous antagonistic bacteria against M. phaseolina causing charcoal rot in soybean.

Investigation of Biological Control of Trichoderma Formulations and Its Mutant Type Related to Chemical Treatments in the Control of Soybean Charcoal Rots Disease

In order to study biological control of soybean charcoal rot disease using multiple mutant Trichoderma formulations with gamma ray, an experiment under greenhouse conditions was performed in the years 2017 and 2018 at Karaj Nuclear Agriculture Research Institute. Beside control the experiment consisted of 16 treatments including chemical and commercial fungicides and inoculation of mutant and non-mutant soybean with Trichoderma fungi. The results showed that the effect of treatments was significant for all morphological and physiological characteristics of soybean. The use of Trichoderma treatments had a positive influence on plant morphological characteristics such as pod number, stem dry weight, stem length, number of branches and physiological traits such as peroxide, chlorophyll a, chlorophyll b and carotenoids. As a result, they increased the yield so that the highest average of 11.75 g per pot was registered to the seed coating treatment with wild Trichoderma (PW). The use of fungal treatments increases proline and malondialdehyde content and the incidence of disease is reduced by using Trichoderma.

Potential of few fungicides and plant extracts for managing charcoal rot of soybean caused by Macrophomina phaseolina (Tassi) Gold. in Madhya Pradesh, India

Charcoal rot disease of soybean caused by Macrophomina phaseolina is a serious problem in most of the soybean growing area of Madhya Pradesh. In this study, seven plant extracts viz., leaves of Azadirachta indica, Citrus limon, Polyalthia longifolia, Parthenium hysterophorus and Ricinus communis, bulb of Allium sativum and Allium cepa and eight fungicides viz., Captan (0.25%), Mancozeb (0.25%), Carbendazim + Mancozeb (25%), Thiophanate Methyl (0.1%), Pyraclostrobin (0.2%), Carbendazim (0.1%) and Blue copper (0.3% ) were evaluated for an effective management of charcoal rot of soybean caused by M. phaseolina (Tassi) Goid under in vitro and in vivo condition. Among plant extracts, garlic clove extract was found most effective showing 77.3 % growth inhibition and poor microslerotia formation of M. phaseolina by 77.3 % followed by parthenium leaf extract (75.2% inhibition) at 15 % concentration. Two soil drenching of garlic clove extracts @ 15.0 % concentration also found most effective for the management of disease under field condition recorded minimum disease incidence (13.5%) and highest yield (14.6q/ha). Among fungicides, Carbendazim (0.1%) and Thiophanate Methyl (0.1%) showed 100 % inhibition of radial growth and microsclerotia production of M phaseolina under in vitro condition. Two soil drenching of Carbendazim @ 0.1% found to be most effective for the management of charcoal rot of soybean under field condition showing minimum disease incidence (5.36%) and producing highest yield (16.0 q/ha) followed by Thiophanate Methyl. These results suggested that the toxic effect of Carbendazim and Thiophanate Methyl and A. sativum inhibited maximum mycelium growth in vitro and provide management of charcoal rot disease under field conditions.

Effect of silicon compounds against Macrophomina phaseolina the causal agent of soybean charcoal rot disease

This work was designed to study the efficacy of two types of silicon compounds (sodium silicate and potassium silicate) to control charcoal rot disease caused by Macrophomina phaseolina in vitro, under greenhouse and field conditions. In vitro study showed that sodium and potassium silicate at all concentration were effective on inhibiting the growth of the pathogen. Generally, sodium silicate significantly reduces pathogen growth than potassium silicate (29.02% and 19.34%, respectively). Under greenhouse conditions, treatments with sodium silicate caused the highest percentage of disease reduction of charcoal rot disease (37.8%), compared with infected control plants. Sodium silicate treatment increased the root, stem and leaves thickness layers of cortex (CO) and pith (PI) compared to untreated soybean plants. Under field conditions, application of sodium silicate in controlling charcoal rot disease showed significant reduction of disease severity in both tested seasons (56% and 42%, respectively) as well as increased the yield of soybean by (136.7% and 97.6%, respectively). The study concluded that application of sodium silicate could be useful in reducing charcoal rot diseases under greenhouse and field conditions.

콩 균핵마름병을 일으키는 Macrophomina phaseolina에 대한 살균제 효과 검정

콩 균핵마름병을 일으키는 Macrophomina phaseolina에 대한 살균제 효과 검정

English

English

Identification of Soybean Genotypes Resistant to Charcoal Rot by Seed Inoculation With Macrophomina phaseolina

Soybean charcoal rot is a widespread root disease caused by the fungus Macrophomina phaseolina, a natural soil inhabitant that has great pathogenic variability and high survival capacity under adverse conditions. There are no registered fungicides or genotypes genetically resistant to this disease, although differences in susceptibility have been observed. As the fungus is a seed-borne pathogen, screening methods based on seed inoculation are quick and efficient. The objective of this work was to assess the efficiency of soybean seed infestation by incubation for 48 h with colonies of M. phaseolina, comparing two germination environment methods (germination paper or in pots with substrate), and to correlate the relative germination of genotypes of both methods with the severity of charcoal rot observed in a field test. The results showed that 48 h were sufficient to infest seeds and reduce the germination. The germination in paper was higher at 5 days after sowing (DAS) than that in pots at 8 DAS in a greenhouse. Both environments exhibited a highly negative correlation between seed germination and field disease severity (r = -0.775 in germination paper and r = -0.779 in pots with substrate). It is recommended that the germination test be performed in germination paper due to practicality and economy of space, material, and labor besides the better control of the environment.

Effectiveness of a Seed Plate Assay for Evaluating Charcoal Rot Resistance in Soybean and the Relationship to Field Performance.

Charcoal rot of soybean, caused by Macrophomina phaseolina, is a disease of economic significance in the United States. Although there are soybean cultivars with moderate resistance, identifying and quantifying resistance is challenging. Existing assays are time consuming, and results are often highly variable. The objectives of this research were to (i) create a reproducible seed plate assay (SPA) for charcoal rot resistance and (ii) correlate field-based disease assessments with SPA results on diverse soybean accessions. To develop the SPA, surface-disinfected seeds from eight soybean genotypes (representing three susceptible and five resistant cultivars) were placed on water agar plates inoculated with M. phaseolina. After incubation at room temperature in darkness for 7 days, percent germination was determined for each cultivar relative to the germination on noninoculated plates. Results from SPA were in general agreement with published responses. None of the soybean genotypes showed complete resistance to M. phaseolina. For the second objective, charcoal rot resistance in 18 soybean accessions was assayed with SPA, and results were analyzed for correlation with field disease assessments from Stuttgart, AR, from 2011 to 2014 and from Rohwer, AR, in 2011 and 2012. SPA consistently categorized soybean genotype resistance compared with field disease assessment averages, and results were consistent with previously published resistance determinations. SPA was significantly correlated with percent height of internal stem discoloration (PHSD) at Stuttgart from 2011 to 2013 and in 2012 at Rohwer, with root and stem severity (RSS) at Rohwer in 2012, and with tap root colonization (CFU) at Stuttgart in 2012. SPA was significantly correlated to yield at Stuttgart in 2011, 2013, and 2014, and in 2011 and 2012 at Rohwer. Yield was not correlated to RSS, PHSD, or CFU at either location or in any year. Therefore, SPA is a reproducible and rapid assay for charcoal rot resistance in soybean and is significantly associated to field performance.

QTL Mapping of Charcoal Rot Resistance in PI 567562A Soybean Accession

Charcoal rot of soybean [Glycine max (L.) Merr.], caused by the soilborne fungus Macrophomina phaseolina (Tassi) Goid., has ranked among the most important soybean diseases in the United States. Disease management is typically done in a multifaceted approach through crop rotation, tillage, irrigation, and seed treatments aimed at minimizing damage caused by the pathogen. Development of genetic resistance to charcoal rot appears to be the most efficient strategy to control the disease; however, there are no reports of genetic regions associated with resistance to the disease. The objective of this study was to identify quantitative trait loci (QTLs) governing resistance to charcoal rot in soybean using a biparental population of PI 567562A (resistant) × PI 567437 (susceptible). A total of 140 F2–derived lines were genotyped with 5403 single nucleotide polymorphism (SNP) markers covering 20 chromosomes, of which 2283 were polymorphic. Resistance to charcoal rot was evaluated in the F2:3 lines using the cut‐stem inoculation technique under greenhouse conditions. The QTL mapping analysis indicated one QTL on chromosome 15 explaining 29.4% of phenotypic variation, and two QTLs on chromosome 16 explaining 25.4 and 8.4% of phenotypic variation for resistance to M. phaseliona. To our knowledge, this is the first report of genomic regions harboring resistance to charcoal rot in soybean, and it may facilitate breeding and molecular engineering progress to combat charcoal rot disease in the future.

Phosphorus fertilization reduces the severity of charcoal rot (Macrophomina phaseolina) and the arbuscular mycorrhizal protection in soybean

AbstractThe effects of phosphorus (P) application on the relationship between the arbuscular mycorrhizal fungus (AMF) Rhizophagus intraradices and the pathogen Macrophomina phaseolina (charcoal rot) affecting soybean (Glycine max L.) are unknown. We evaluated the effects of P on both the severity of the pathogen and the AMF protection against the charcoal rot in soybean. We conducted greenhouse experiments with a randomized multifactorial design with ten replications. The treatments were: two concentrations of P as superphosphate (0 and 50 kg of P ha−1), inoculated and non‐inoculated with the AMF R. intraradices, and infected and non‐infected with M. phaseolina. Soybean was seeded in pots containing 1 kg of sterilized substrate soil : sand : perlite (7 : 3 : 2). When soybean completed pod formation (R4 phenological stage), the plants were harvested. Plant parameters, mycorrhizal colonization, and disease severity were measured. The presence of M. phaseolina negatively affected soybean biomass, but AMF inoculation improved it. Phosphorus reduced AMF colonization but not arbuscules percentage. Moreover, both P and AMF inoculation had a negative effect on disease severity, although P also reduced mycorrhizal protection. These results suggest that phosphorus application could reduce disease severity, but can simultaneously partially reduce the AMF protection against the pathogen. These effects should be considered in agricultural integrated management practices of soybean.

Disease incidence of charcoal rot (Macrophomina phaseolina) on soybean in north-western Argentina and genetic characteristics of the pathogen

Charcoal rot of soybean (Glycine max (L.) Merr.), caused by Macrophomina phaseolina (Tassi) Goid., is an economically important disease worldwide. In recent years, charcoal rot has become a concern for farmers in north-western Argentina. The present work aimed to (1) evaluate disease incidence of charcoal rot; (2) assess morphological and genetic characteristics of M. phaseolina isolates from soybean and other hosts collected in north-western Argentina; and (3) compare genetic diversity between soybean isolates of M. phaseolina from Argentina and the USA. Incidence of charcoal rot evaluated in 11 locations during five growing seasons (2008–2012) was 1%, 1%, 1%, 5–10% and 90%, respectively, indicating a gradual increase over the cropping seasons. Cluster analysis by AFLP of Argentinean isolates exhibited one main group, with isolate Mp56 separated at a genetic distance of 0.70. Four main groups were identified using SSR markers at the same genetic distance, with Mp56 and Mp53 separated from them. There was no clear association between AFLP, SSR profiles, morphological characteristics or host of origin within isolates from Argentina. However, using principal coordinate analysis of SSRs, 22 isolates of M. phaseolina from soybean from north-western Argentina were clearly distinguished from 11 isolates previously collected from two states in the USA. Our results confirmed the increasing importance of charcoal rot in north-western Argentina and identified characteristics of isolates that may be useful for breeding for disease resistance and developing integrated management programmes for charcoal rot in Argentina in the future.

Antimicrobial activity against Macrophomina phaseolina and the control of charcoal rot in soybeans using the homoeopathic drugs Sepia and Arsenicum album

ABSTRACT: The aim of this study was to evaluate the control of charcoal rot in soybeans using Sepia and Arsenicum album homeopathic solutions in dynamizations of 6, 12, 24, 36 and 48CH (hahnemanian centesimal scale), in addition to verify the antimicrobial activity of these treatments against Macrophomina phaseolina. Additional treatments were also used, including distilled water and a hydroalcoholic solution of 30% ethanol. In vitro tests were performed to analyze the number of micro-sclerotia and the mycelial growth of the fungus. In vivo assays were used to evaluate the progress of the disease and the size of the lesions. For the area under the mycelial growth curve (AUMGC), A. album had no effect, however, Sepia reduced up to 32% of the fungal growth. For micro-sclerotia there was no statistical difference. For the area under the disease progress curve (AUDPC), both Sepia and A. album in 24CH dynamization reduced fungal growth up to 50% and 70% in the first and second assays, respectively, compared to control treatments. These results indicate the potential of these homeopathic drugs for controlling soybean charcoal rot.

ANTIFUNGAL ACTIVITY OF ROSEMARY EXTRACT ON MACROPHOMINA PHASEOLINA AND CHARCOAL ROT CONTROL IN SOYBEAN

The charcoal rot caused by the fungus Macrophomina phaseolina is an important disease of soybean (Glycine max), for which there is no recommended fungicides or resistant cultivars. The aim of this study was to investigate the antifungal activity and the control of charcoal rot of soybean stem with an aqueous extract of rosemary at concentrations of 1%, 2.5% and 5%. The in vitro assays were carried out to evaluate the mycelial growth and the production of micro-sclerotia in solid and liquid culture media, while in vivo assays evaluated the disease progress. The rosemary extract reduced the fungal growth on solid and liquid media by 44% and 74%, respectively, and the number of micro-sclerotia by 61%. There was a disease reduction of 53% and 56% in the area under the disease progress curve in the first and in second assay, respectively. These results indicate the potential of the rosemary extract for controlling charcoal rot in soybean.