Biocontrol of Soybean Charcoal Root Rot Disease by Using Trichoderma spp.

ABSTRACTMacrophomina phaseolina (Tassi) Goid remains the prevailing causal agent of charcoal rot disease that significantly suppresses the yield of a variety of oilseed crops. Its wide host range and ability to survive under arid conditions, coupled with the ineffective use of fungicides against it, have spurred scientific endeavours for alternative avenues to control this phytopathogen. Hence, the present study aimed to provide empirical evidence of the efficacy of three fungal isolates (T2, T10 and T12) of Trichoderma harzianum as biological control agents against charcoal rot in soybean (Glycine max L.). The results of the in vitro studies revealed that all three fungal isolates significantly inhibited the growth of M. phaseolina phytopathogen, with T12 showing considerably higher inhibition effect than T2 and T10 isolates. T12 inhibited the growth of M. phaseolina in the dual culture (72.31%) and volatile production (63.36%) assays, and the hyperparasitism test indicated cell lysis following the interactions with T12 mycelia. T12 isolate was mostly effective in field experiments, observable in the attained minimum plant disease indices both in the soil incorporation (11.98%) and seed inoculation (5.55%) treatments, in comparison to isolates T2 and T10. Moreover, the stem and root lengths, as well as the seed weight, were considerably increased, as compared to the control. Hence, the findings reported in the present study supported the applicability of T12 isolate as possible alternative to fungicides for the control of charcoal rot in soybean.

harcoal rot (Macrophomina phaseolina (Tassi) Goidanich) of soybean (Glycine max (L.) Merr.) is a disease of economic significance throughout the world.Pathogenicity of 14 isolates of Macrophomina phaseolina was tested on soybean cv.Giza 21 under greenhouse conditions.They capable to infect soybean plants caused charcoal rot on the basil stem with various degrees of diseases severity.Isolate S13 caused the highest charcoal rot severity (60%) followed by isolates S11 and S8 (57.9 and 56.3 %, respectively).The positive effect of two inducer chemicals, i.e riboflavin (vitamin B2) and.thiamine (vitamin B1) on the induction of systemic resistance in soybean against charcoal rot disease as well as biochemical changes associated with these treatments in soybean plants was recorded.Under greenhouse conditions, the dose effect of 0.1 to 15 mM riboflavin and thiamine showed that 2.5 mM of riboflavin and 5 mM of thiamine was sufficient for maximum induction of resistance; higher concentration did not increase the effect.On the other hand, plants treated with riboflavin and thiamine and inoculated with pathogen grow higher than plants treated with sterilized distilled water (SDW) and inoculated with pathogen, while increased fresh and dry weight of soybean plants.At 10 mM concentration of riboflavin and thiamin recorded the highest dry and fresh weights.In time course observation, it was observed that riboflavin and thiamine treated soybean plants were inducing resistance one day after treatment and reached its maximum level from 5 to 7 days in case of riboflavin and 6-8 days in case of thiamine and then decreased.Under field conditions, the percentages of damping-off, root rot and/or charcoal rot severity were significantly reduced due to soaking the seeds in any of riboflavin and thiamine before sowing in both trial seasons (2008-2009 and 2009-2010).Also, these treatments significantly increased nodule numbers plant -1 , fresh and dry weight of nodules plant -1 in both experimental seasons.Generally, thiamine gave the best results in most cases under greenhouse and field conditions.In physiological studies, activity of defense-related enzymes, including peroxidase, polyphenol oxidase, phenylalanine ammonia lyase, pathogenesis related (PR) protein (chitinase), were increased in inoculated and non-inoculated plants treated with the thiamine and riboflavin individually, during the experimental period.In general, activity of these enzymes begins to accumulate after two days of treatment and reached maximum levels at 8, 6, 8 and 8 days for PO, PPO, PAL and chitanase, respectively, then the activities of these C

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.

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 .

Background and Aim: Soybean (Glycine max (L.) Merrill), commonly known as the “golden bean,” is a globally significant leguminous crop owing to its high nutritional value and it is severely limited by various diseases, which can result in substantial yield losses. To evaluate the efficacy of newly approved and recommended fungicides against charcoal rot disease of soybean under in vitro conditions. Study Design: Complete randomized block design. Place of Study: Division of Crop Protection, ICAR-National Soybean Research Institute, Khandwa Road, Indore. Methodology: Macrophomina phaseolina was isolated from charcoal rot–infected plants and cultured on PDA. The fungus produced white to grey mycelium with black microsclerotia (80–120 µm). Pure cultures were obtained using hyphal tip transfer on PDA acidified with 0.2% lactic acid and maintained by weekly subculturing. Fungicidal efficacy was evaluated in vitro using the poison food technique with foliar fungicides (0.05–0.2%) and seed treatment fungicides (0.025–0.125%). A 4 mm mycelial disc from a 4-day-old culture was inoculated onto treated PDA plates and incubated at 26 ± 1°C. Percent mycelial growth inhibition was calculated using Vincent’s formula. Results: Fungicides, concentrations, and their interaction significantly affected mycelial growth inhibition in foliar fungicides (P < 0.0001), while seed dressing fungicides showed no significant differences. Among foliar fungicides, picoxystrobin + propiconazole was most effective, with maximum mean inhibition of 92.79%. All seed dressing fungicides showed complete (100%) inhibition of charcoal rot at all concentrations. Conclusion: Picoxystrobin + propiconazole was the most effective foliar fungicide against the charcoal rot pathogen, while all tested seed treatments achieved complete mycelial inhibition. Further field evaluations are required to confirm their effectiveness under field conditions in soybean.

Sunflower (Helianthus annuus L.) is considered as one of the most important oilseed crops in Egypt and worldwide. It is being infected with many pathogens, among these pathogens Macrophomina phaseolina (Tassi) Goid, the causal agent of charcoal rot is the most prevalent one, and responsible for severe economic losses on sunflower production. Fourteen isolates of M. phaseolina were collected from naturally infected sunflower plants. Pathogenicity tests revealed that tested isolates varied significantly in their pathogenic capabilities. But all of the tested isolates were pathogenic and incited the symptoms of pre- and post-emergence damping-off as well as symptoms of charcoal rot. In this study, antagonistic capabilities of 26 isolates of Trichoderma spp. were investigated under both laboratory and greenhouse conditions. In vitro, T. harzianum (T8) and T. hamatum (T12) proved to have high antagonistic capability against M. phaseolina fungus with inhibition percentage of 62.13% and 61.33%, respectively. Furthermore, these two isolates proved to have a high ability to control charcoal rot disease. Data of greenhouse experiments showed that application of T. harzianum (T8) and T. hamatum (T12) decreased charcoal rot disease severity by 30.33 and 24.16% respectively. Time of application played a critical role to increase the efficiency of Trichoderma spp. to control charcoal rot. In this experiment Trichoderma was implemented into soil at different application dates to study the effect of application date on the efficiency of bioagents to control charcoal rot. Results of this experiment showed that the highest reduction in disease severity occurred when T. harzianum (T8) was applied seven days before soil infestations with M. phaseolina (38.40%). Data also demonstrated that application of either T. harzianum or T. hamatum led to significant increases in the percentage of survival plants with 72.5% and 68.33%, respectively. This study suggests using Trichoderma spp could be an efficient method to control sunflower charcoal rot.

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.

Soybean (Glycine max L.) is a leading oil seed crop in the world. Owing to climate change, its production is challenged by many forms of biotic and abiotic stresses. Charcoal rot (Macrophomina phaseolina (Tassi) Goid) disease incidence is aggravated with the increase in soil and air temperatures. Charcoal rot disease in soybean is likely to gain its economic importance with the increase in global temperature. Apart from soybean, this pathogen has a wide host range including some economical crops like sorghum and maize. So far, complete resistance to this pathogen has not been identified in any of the crop species. Field screening techniques based on the colony-forming unit index (CFUI) and estimation of root stem severity (RSS) and glasshouse screening technique, such as cut-stem inoculation, are mainly employed in identifying charcoal rot resistance sources in soybean. High-throughput screening can be possible through cut-stem inoculation technique. There are reports indicating the correlation between field screening results and results obtained from this technique, and researchers have used this technique in understanding the genetic architecture of charcoal rot resistance and in identifying candidate genes and QTL governing charcoal rot resistance. Drought conditions are favourable for disease incidence and aggressiveness. Not all drought-tolerant genotypes are resistant to charcoal rot but some drought-tolerant genotypes are found to be moderately resistant to the disease. Significant yield losses are reported due to this disease even under irrigated conditions. Research is gaining momentum in developing high-throughput, reliable and repeatable glasshouse and in vitro screening techniques to identify stable sources of resistance and in understanding the genetic architecture of charcoal rot resistance. Breeding programs are under way for developing high-yielding, charcoal-rot-resistant and drought-tolerant cultivars.

  Charcoal rots (Macrophomina phaseolina (Tassi) Goidanich) of soybean (Glycine max (L.) Merr.) is a disease of economic significance throughout the world. Pathogenicity of 14 isolates of M. phaseolina was tested on soybean cv. Giza 21 under greenhouse conditions. The obtained data indicated that all the obtained isolates were able to attack soybean plants and caused charcoal rot on the basal stem with various degrees of diseases severity. M. phaseolina isolate S13 caused the highest charcoal rot severity (60%) followed by isolates S11 and S8 (57.9 and 56.3%, respectively). The effect of two inducer chemicals, that is, riboflavin (B2) and thiamine (B1) on the induction of systemic resistance in soybean against charcoal rot disease as well as biochemical changes associated with these treatments in soybean plants was investigated. Under greenhouse condition, the dose effect of 0.1 to 15 mM riboflavin and thiamine showed that 2.5 mM of riboflavin and 5 mM of thiamine was sufficient for maximum induction of resistance; higher concentration did not increase the effect. On the other hand, plants treated with riboflavin and thiamine and inoculated with pathogen grew higher than plants treated with sterilized distilled water (SDW) and inoculated with pathogen and increased fresh and dry weight of soybean plants. 10 mM concentration of riboflavin and thiamin recorded the highest dry and fresh weight compared with the control. In time course observation, it was observed that riboflavin and thiamine treated soybean plants induced resistance one day after treatment and reached its maximum level from 5 to 7 days in the case of riboflavin and 6 to 8 days in the case of thiamine and then decreased. Under field conditions, the percentage of damping-off, root rot and/or charcoal rot severity were significantly reduced due to soaking of the seeds in any of riboflavin and thiamine before sowing compared with the control treatment (seed treated with water) in both seasons (2008 to 2009 and 2009 to 2010). Also, these treatments significantly increased nodule numbers per plant, fresh and dry weight of nodules per plant compared with the control in both seasons. Generally, thiamine gave the best results in most cases under greenhouse and field conditions. In physiological studies, activity of defense-related enzymes, including peroxidase (PO), polyphenol oxidase (PPO), phenylalanine ammonia lyase (PAL), pathogenesis related (PR) protein (chitinase), were increased in the inoculated and non-inoculated plants treated with the thiamine and riboflavin respectively, compared with the control during the experimental period. In general, activity of these enzymes began to accumulate after two days of treatment and reached maximum levels at 8, 6, 8 and 8 days for PO, PPO, PAL and chitinase, respectively then the activities of these enzymes decreased progressively. On the other hand, total phenols and lignin increased in soybean plants inoculated with M. phaseolina and treated with thiamine and riboflavin. The highest accumulation of phenols was recorded 6 days after treatment, while lignin recorded the highest level at the 10th day from application. These results suggested that these chemicals mayplay an important role in controlling the soybean charcoal rot disease, through induction of systemic resistance in soybean plants.   Key words: Soybean, charcoal rot, thiamine, riboflavin, induced resistance.

Charcoal rot disease in soybean is caused by the fungus Macrophomina phaseolina, which is believed to infect plants from soil through the roots by a toxin-mediated mechanism. Soybean genotypes exist which are susceptible (S) or moderately resistant (MR) to charcoal rot, but the mechanism of resistance is not known. Significantly (p ≤ 0.05) higher levels of phenolics, seed coat lignin, isoflavones, sugars, and total boron were observed in MR genotype than in S genotype seeds under irrigated and nonirrigated and under experimental M. phaseolina infested and noninfested conditions, indicating a possible association of these substances with resistance to toxin-mediated infection.

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.

Charcoal rot (CR) disease caused by Macrophomina phaseolina is responsible for significant yield losses in soybean production. Among the methods available for controlling this disease, breeding for resistance is the most promising. Progress in breeding efforts has been slow due to the insufficient information available on the genetic mechanisms related to resistance. Genome-wide association studies (GWAS) enable unraveling the genetic architecture of resistance and identification of causal genes. The aims of this study were to identify new sources of resistance to CR in a collection of 459 diverse plant introductions from the USDA Soybean Germplasm Core Collection using field and greenhouse screenings, and to conduct GWAS to identify candidate genes and associated molecular markers. New sources for CR resistance were identified from both field and greenhouse screening from maturity groups I, II, and III. Five significant single nucleotide polymorphism (SNP) and putative candidate genes related to abiotic and biotic stress responses are reported from the field screening; while greenhouse screening revealed eight loci associated with eight candidate gene families, all associated with functions controlling plant defense response. No overlap of markers or genes was observed between field and greenhouse screenings suggesting a complex molecular mechanism underlying resistance to CR in soybean with varied response to different environments; but our findings provide useful information for advancing breeding for CR resistance as well as the genetic mechanism of resistance.

Soybean is a leading agronomic crop and contributes to food and agricultural security with expanding production areas in diverse regions around the world. Although soybean is challenged by several diseases and pests and progress has been made in understanding and managing some of these pathogens and pests, charcoal rot, incited by the soil-borne fungal pathogen Macrophomina phaseolina, has received little attention. M. phaseolina has a broad host range and is capable of attacking and infecting several groups of plant species, including soybean. Charcoal rot symptoms on soybean appear more commonly during hot and dry weather conditions, and are associated with drought stress. In recent years, it has become more important to develop management strategies to control charcoal rot in soybean fields. Understanding the genetics of this pathogen as well as its interactions with plant hosts will help in developing effective control and management strategies. The biology of M. phaseolina, its genetics, and plant–fungal relationships are reviewed herein. In addition, a discussion of potential opportunities utilizing modern tools to enhance genetic resistance against charcoal rot is also presented.

The 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.

Soybean (Glycine max (L.) Merrill) is a major oil-seed crop of global importance, but its productivity is severely threatened by charcoal rot caused by Macrophomina phaseolina, a necrotrophic fungus with a wide host range. The ITS region of the pathogen was amplified which yielded a 598 bp sequence and showed 97.15% identity and 100% query coverage in BLAST analysis. Following molecular confirmation, the in-vitro efficacy of twelve fungicides, comprising six single compounds and six combinations was assessed against M. phaseolina using the poisoned food technique at 100, 250 and 500 ppm. All tested fungicides significantly inhibited mycelial growth relative to the untreated control, though performance varied across treatments. Complete suppression (100% inhibition) was consistently recorded with Carbendazim 25% + Mancozeb 50% WS, Carbendazim 50% WP and Tebuconazole 25.9% w/w EC at all concentrations. In contrast, Penflufen 13.28% + Trifloxystrobin 13.28% FS and Azoxystrobin 11% + Tebuconazole 18.3% SC were the least effective with 61.18% inhibition at 100 ppm. The findings highlight the superior efficacy of benzimidazole and triazole based fungicides, alone or in combination with contact fungicides, for effective suppression of M. phaseolina. These results provide valuable insights for developing effective fungicidal strategies for the management of charcoal rot in soybean under field conditions.