Sclerotium Rolfsii Research Articles

Comparative efficacy of different chemical fungicides against Sclerotium rolfsii (sacc.) causing collar rot of chickpea (Cicer arietinum L.)

Present investigation was undertaken for efficacy of fungicides like i.e., carboxin 37.5% + thiram 37.5% WS (vitavax), pyraclostrobin 100 g/L CS, propiconazole 25% EC, hexaconazole 5% EC, thiophanate methyl 70% WP, carbendazim 50% WP, mancozeb 75% WP, chlorothalonil 75% WP and captan 70% + hexaconazole 5% WP were evaluated in-vitro at three concentrations viz., 100, 125 and 200 ppm concentration against S. rolfsii on PDA by poisoned food technique. The result revealed that increase in concentration of the fungicides caused increased inhibition of mycelial growth of pathogen. Among these, carboxin 37.5% + thiram 37.5% WS (vitavax) was completely inhibited mycelial growth of pathogen at 100 ppm, 125 ppm & 200 ppm. Followed by hexaconazole 5% EC in mycelial growth inhibition of 95.44, 97.22 and 100% at 100, 125 and 200 ppm, respectively. At 200 ppm both hexaconazole 5% EC and carboxin 37.5% + thiram 37.5% WS (vitavax) is statistically at par in growth inhibition. While, mancozeb 75% WP was found least effective at all concentrations against S. rolfsii. Most effective in-vitro evaluate fungicides tested for their efficacy against disease under pot experiment along with treatment application methods viz., pre-emergence drenching, seed treatment and integration of both seed treatment and post emergence seedling drenching at 7 days after germination (7 DAG) against collar rot disease of chickpea in pot experiment. All the treatments proved significantly superior when compared with inoculated control. Maximum percent reduction in PESR (100.00%) was recorded in vitavax power applied through seed treatment followed by hexaconazole recorded (90.91%) reduction in PESR. Maximum percent reduction in PESM (62.50%) was recorded in hexaconazole applied through integration of seed treatment & post emergence seedling drenching at 7 DAG. Which, was followed by vitavax power observed (50.00%) reduction in PESM. Seed treatment alone reduced PESR while, integration of seed treatment and post emergence seedling drenching at 7 DAG also reduced PESM. Among treated pots highest grain yield recorded (45.90 g/pot) in hexaconazole applied through integration of integration of seed treatment and post emergence seedling drenching at 7 DAG followed by vitavax power (43.33 g/pot).

First report of basal stem rot on sugarcane (var. Badila) caused by Sclerotium rolfsii in China.

Badila (Saccharum officinarum) is one of the important chewing cane in south China. During the year 2019-2020, as much as 60.2%-87.5% of sugarcane plants stem showed red rot developments were observed in the fields of Yongning District, Nanning city, Guangxi province. Symptomatic plants showed red rot at basal stem nodes and sheath, when the disease serious, the epidermis and aerial roots decomposed and exfoliated, then formed sclerotiums, the upper stem also occurred the symptom. Infected plant tissues were dissected into small pieces with 0.1 × 0.1cm in size and surface sterilized in 0.1% HCl2 for 2 min, followed by 75% ethanol for 30 s, rinsed three times with sterile distilled water. Then the tissues were placed onto potato dextrose agar (PDA) plates and incubated at 25 °C for 3 days. Numerous white globoid sclerotia were formed on PDA after 5 days of growth. The sclerotia (2 to 3 mm in diameter) were white at first and then gradually turned dark brown. Aerial mycelia usually formed many narrow hyphal strands 4 to 9 μm wide. Five uniform isolates were obtained from diseased sugarcane plants. Pathogenicity of representative strain W1 was confirmed by inoculating 120-day-old Badila plants grown in field. Five plants were inoculated with colonized agar discs (6mm in diameter) by applying toothpick tips to the lower part of the stem. Five non-inoculated plants served as control. The inoculated and non-inoculated plants were sprayed sterile water then incubated with plastic film for maintained high moisture. All the plants were placed inside of a growth chamber at 26 ± 2°C with a 14-h photoperiod and 80% relative humidity. All inoculated plants showed red rot at stem and sheath after 2 weeks, whereas the control plants were symptomless. By the third week, mycelium and sclerotia developed on the crown on the inoculated plants. The fungus was re-isolated from the artificially inoculated plants. To confirm the species-level identification, partial of the ribosomal DNA internal transcribed spacer (ITS), mitocondrial small subunit (SSU), and nuclear ribosomal large subunit (LSU) regions of representative strain W1 were amplified and sequenced using the primers pairs ITS1/ITS4 (White et al. 1990), ITS-Fu-F /ITS-Fu-R and SRLSU1//SRLSU2 (Kumar et al., 2016), respectively. The resulting ITS, SSU and LSU sequences were deposited in GenBank (GenBank accession no. MW620994, MW617878, and MW617872) and shared 99.42%, 100% and 100% sequence identity with Athelia rolfsii isolate (JN017199, OM319631, and MT225781). Phylogenetic analysis conducted with neighbor-joining (NJ) method using MEGA6.0 revealed that the isolate share a common clade with reference sequence of A. rolfsii in GenBank Data Library. Based on morphological and molecular characteristics, the fungus was identified as A. rolfsii (anamorph: Sclerotium rolfsii) (Paul et al. 2017; Paparu et al. 2020). Although S. rolfsii has been reported causing sugarcane sett rot in Australia (Bhuiyan et al., 2019) and seedlings of sugarcane in Indian (Gopi et al., 2023), as we know, this is the first report of sugarcane basal stem rot disease caused by this fungus in China. This study will be helpful for the prevention and control sugarcane basal stem rot in the future.

Biocontrol potential of Bacillus velezensis SEC-024A against southern blight of industrial hemp

Agroathelia rolfsii is the causative agent of southern blight of industrial hemp, which is a soil-borne infection resulting in grave economic losses in industrial hemp (Cannabis sativa L.). Chemical pesticides are currently the primary means of controlling this disease, but their use is harmful to human health as well as to the environment. Urgent action is needed to screen eco-friendly biocontrol agents against this pathogen. An endophytic bacterium SEC-024A was isolated from the leaf tissue of industrial hemp and exhibited a significant antagonistic effect on A. rolfsii, with a plate inhibition rate of 80.5 % and a pot control effect of 74.1 %. Through whole genome sequencing, SEC-024A was identified to be Bacillus velezensis. It contained multiple gene clusters involved in secondary metabolite biosynthesis and the genes that promote plant growth, colonization, and pathogen defense. Bacillus velezensis SEC-024A produces volatile organic compounds (VOCs) that serve as its primary fungistatic agents. Nine VOCs produced by SEC-024A were detected through gas chromatography-mass spectrometry. These VOCs were individually tested for their antifungal effects. Four volatiles, namely isobutyric acid, tiglic acid, trans-2-octenal, and 2-decanone, exhibited notable inhibitory effects on A. rolfsii with EC50 values of 0.012, 0.038, 0.009, and 0.046 μL/mL, respectively. Additionally, trans-2-octenal demonstrated broad-spectrum antifungal activity against various soil-borne pathogens. Together, this study suggests that B. velezensis SEC-024A holds promise as a novel microbial agent for improving plant growth and controlling diseases.

Study of area under disease progressive curve (AUDPC) on collar rot disease of Indian bean caused by Sclerotium rolfsii in South Gujarat

Study of area under disease progressive curve (AUDPC) on collar rot disease of Indian bean caused by Sclerotium rolfsii in South Gujarat

Biological Suppression of Sclerotium rolfsii in Groundnut Cultivation: A Path Towards Sustainable Disease Management

Stem rot of groundnut caused by Sclerotium rolfsii Sacc, is a major soil borne disease which impact on groundnut cultivation both in India and globally. The primary objective of this study was to assess the antagonistic potential of biocontrol agents against the pathogen, both individually and in combination, under In vitro and glasshouse conditions. The results of the present investigation indicated that the application of microbial consortia was more effective against Sclerotium rolfsii than individual bioagents. Specifically, seed treatment with microbial consortia MC1, MC2, MC3, and MC4 resulted in lower disease incidence with 13.80%, 16.01%, 20.0%, and 22.60% respectively, compared to the pathogen check, which had a 74.12% PDI. Additionally, these treatments also enhanced plant growth through improved plant growth-promoting traits under glasshouse conditions.

In vitro exploration of phytoextracts against stem rot of white onion (Allium cepa L.) caused by Sclerotium rolfsii Sacc.

In vitro exploration of phytoextracts against stem rot of white onion (Allium cepa L.) caused by Sclerotium rolfsii Sacc.

Biocontrol Activity of Bacillus altitudinis CH05 and Bacillus tropicus CH13 Isolated from Capsicum annuum L. Seeds against Fungal Strains.

In this study, seed-surface-associated bacteria from fresh fruits of Capsicum spp. were analyzed to explore potential isolates for biocontrol of phytopathogenic fungal strains. A total of 76 bacterial isolates were obtained from three different species of chili pepper (C. annuum L., C. pubescens R. & P., and C. chinense Jacq.), and two isolates were selected via mycelial growth inhibition assays based on their production of volatile organic compounds (VOCs) against six fungal strains. Genomic analysis identified these isolates as Bacillus altitudinis CH05, with a chromosome size of 3,687,823 bp and with 41.25% G+C, and Bacillus tropicus CH13, with a chromosome size of 5,283,706 bp and with 35.24% G+C. Both bacterial strains showed high mycelial growth inhibition capacities against Sclerotium rolfsii, Sclerotinia sp., Rhizoctonia solani, and Alternaria alternata but lower inhibition capacities against Colletotrichum gloesporoides and Fusarium oxysporum. VOC identification was carried out after 24 h of fermentation with 64 VOCs for B. altitudinis CH05 and 53 VOCs for B. tropicus CH13. 2,5-Dimethyl pyrazine and acetoin had the highest relative abundance values in both bacterial strains. Our findings revealed that seed-surface-associated bacteria on Capsicum spp. have the metabolic ability to produce VOCs for biocontrol of fungal strains and have the potential to be used in sustainable agriculture.

Unveiling the Hidden Enemies: Morphological and Molecular Characterization of Pod Rot Pathogens in Groundnut (Arachis hypogea L.) in India

Pod rot of groundnut is a complex disease caused by multiple pathogens causes significant economic losses. Present study was undertaken to know the pathogens associated with the disease. In Chittoor, Andhra Pradesh, roving survey against pod rot of groundnut revealed association of three fungal species: Sclerotium rolfsii, Rhizoctonia bataticola and Fusarium spp. Molecular analysis with modified CTAB method and performing PCR using ITS1 and ITS4 primers yielded DNA bands of 650-700 bp, 550-600 bp, and 500-600 bp for Sclerotium, Rhizoctonia and Fusarium species, respectively. Sequencing of the rDNA ITS region confirmed the identities of the pathogens as Sclerotium rolfsii, Rhizoctonia bataticola, Fusarium solani, Fusarium oxysporum, and Fusarium keratoplasticum, based on similarity with NCBI reference sequences. This study confirms that Sclerotium rolfsii, Rhizoctonia bataticola and Fusarium spp. are the primary causal agents of pod rot disease in Andhra Pradesh.

An atoxigenic Aspergillus flavus PA67 from Shandong province exhibits potential in biocontrol against toxigenic Aspergillus flavus, Sclerotium rolfsii, and Fusarium proliferatum

Peanuts and corn are susceptible to various soil-borne fungi, leading to significant economic losses. Atoxigenic Aspergillus flavus have been widely used as biocontrol agents for managing aflatoxin contamination because of their minimal environmental impact, strong competitive ability, and sustained inhibition effect. After multiple identifications and cluster amplification pattern (CAP) analysis, three atoxigenic A. flavus PA04, PA10 and PA67 were isolated from peanut samples in Shandong Province, which can reduce aflatoxin levels by up to 90 %. Our study revealed that atoxigenic A. flavus also competed vigorously with Sclerotium rolfsii and Fusarium proliferatum for nutrition and space, achieving notable inhibition rates of up to 90.4 % and 90.6 %, respectively. The supernatants of atoxigenic A. flavus also inhibited the growth of S. rolfsii and F. proliferatum, with PA67 demonstrating the most significant effect. Whole genome sequencing revealed that PA67 contains multiple glycoside hydrolases and metabolites with antifungal activity. The kojic acid production of PA67 was higher than that of PA04 and PA10, reaching 17.48 g/L, which has a significant inhibition on sclerotia germination. PA67 supernatant significantly inhibited the hyphae growth of S. rolfsii and F. proliferatum, and down-regulated genes related to sclerotia and fumonisin formation. This study demonstrates the biocontrol potential of PA67 against three soil-borne fungi and is the first investigation of atoxigenic A. flavus to inhibit S. rolfsii and F. proliferatum.

Catalyst-free synthesis of novel α-trifluoromethylated tertiary alcohols bearing azaarenes as potential antifungal agents

Herein, α-trifluoromethylated tertiary alcohols bearing azaarenes were successfully synthesized via the reaction of 2-methyl azaarenes and CF3-substituted 1,3-diols with high yields under catalyst-free, mild conditions. The antifungal activities against Gaeumannomyces graminis var tritici, Rhizoctonia cerealis, Fusarium graminearum, Rhizoctonia solani, Fusarium moniliforme, Sclerotium rolfsii Sacc were investigated. The bioassay results indicated that the antifungal activity against Gaeumannomyces graminis var tritici was obviously better compared to other five fungi and compound 3dd displayed the highest activity, with an EC50 value of 27.73 μg/mL in vitro.

Antifungal activity of fractions and compounds from <i>Pterocarpus erinaceus</i> poir.1804, (Fabaceae) on selected wood fungi

Extract fractions and compounds from the heartwood and stem bark of Pterocarpus erinaceus were evaluated for antifungal properties. Extraction of the dry and pulverized plant materials was carried out with hexane, ethyl acetate and then methanol. The extracts were fractionated and purified using column chromatography over silica gel to yield p-ethoxylphenylpropanoic acid, angolensin, mixture of sitosterol, stigmasterol and cycloeucalenol from heartwood while friedelane-3-one and lupeol were obtained from the stem bark. The fractions and compounds were active against the test fungi (Aspergillus fumigatus, Coniophora puteana, Fibroporia vaillantii, Fomitopsis pinicoca, Gloeophyllum sepiarium Phaeolus schweinitzii, Rhizopus sp., Serpula lacrymans and Sclerotium rolfsii) at zone of inhibition ranging from 17 – 24 mm. Fibroporia vaillantii showed resistance to the control antibiotic (Ketoconazole and Fluonazole) but was sensitive to five of the fractions. The minimum inhibitory concentration observed was 50 μg/mL against 9 test fungi while the minimum fungicidal concentration was 200 μg/mL.

In-vitro efficacy of fungicides against Sclerotium rolfsii caused stem rot of groundnut

In-vitro efficacy of fungicides against Sclerotium rolfsii caused stem rot of groundnut

Unravelling the Complexity of Ginger Rhizome Rot Disease: A Focus on Pathogen Interactions

ABSTRACTRhizome rot poses a significant threat to ginger cultivation, caused by a complex interaction of pathogens such as Pythium aphanidermatum, Fusarium oxysporum, Ralstonia solanacearum, Sclerotium rolfsii and Meloidogyne incognita. The pathogens were individually inoculated at 75, 105 and 135 days after planting (DAP), as well as in various combinations, to evaluate disease severity and symptom development. Results revealed that R. solanacearum exhibited the highest disease severity and fastest symptom development across all stages of inoculation, followed by P. aphanidermatum, F. oxysporum, S. rolfsii and M. incognita. The combined inoculation of pathogens significantly increased disease incidence and rhizome rot compared to individual inoculations, indicating synergistic interactions among the pathogens. Sequential inoculation experiments demonstrated that pre‐infection by M. incognita exacerbated disease severity, highlighting the role of nematodes in predisposing plants to secondary infections.

Trichoderma Isolates Against Abiotic Stresses and Management of Collar rot of Lentil (Lens culinaris L.) Caused by Sclerotium rolfsii.

A total of 30 native Trichoderma isolates were collected from the Agricultural Research Station, Ummedganj- Kota, Rajasthan, India. Out of which 9 native isolates were evaluated for bio-efficacy against Sclerotium rolfsii. Isolate ARS K-21 exhibited maximum inhibition (89.26%), followed by ARS K-11 (83.70%) in dual culture. Subsequent evaluations revealed the compatibility of efficient isolate ARS K-21 with various bio botanicals displaying minimum inhibition with Vermiwash (1.11-3.70%) followed by Beejamarat (0.38-15.92%) and Brahmastra (7.78-19.68%), while ARS K-11 displayed compatibility onlywith Dasparni ark with a minimum inhibition of 1.11-3.70%. Assessment of abiotic stress tolerance of the isolates revealed that most isolates thrived at 200 mM and 400 mM NaCl salt concentrations, with ARS K-21 and ARS K-24 demonstrating moderate growth levels across higher concentrations, except at 1200 mM. Optimal growth of the isolates occurred at 25and 30°C, with deviations leading to growth inhibition. Isolates ARS K-1, ARS K-11, ARS K-12 and ARS K-21 exhibited resilience to temperature extremes. ARS K-21 has shown exceptional growth proficiency across a wide pH spectrum (pH 5 to 8.5) followed by ARS K- 24, highlighting their versatility. Mass multiplication of efficient isolate ARS K-21 enriched with vermicompost led to the standardization of a dosage (30g/kg soil) for managing collar rot in lentil crops at 5g inoculum per kg soil of S. rolfsii.

Deciphering the defense response in tomato against Sclerotium rolfsii by Trichoderma asperellum strain A10 through gene expression analysis.

The online version contains supplementary material available at 10.1007/s13205-024-04040-4.

Suppressing effects of paper pot transplantation and sulfur material application on southern blight on Jerusalem artichoke

Suppressing effects of paper pot transplantation and sulfur material application on southern blight on Jerusalem artichoke

In vitro exploration of bioagents and fungicides against stem rot of white onion (Allium cepa L.) caused by Sclerotium rolfsii Sacc.

In vitro exploration of bioagents and fungicides against stem rot of white onion (Allium cepa L.) caused by Sclerotium rolfsii Sacc.

Comparative in vitro evaluation of fungicides against collar rot pathogen, Sclerotium rolfsii in elephant foot yam

Amorphophallus or elephant foot yam (Amorphophallus paeoniifolius) popularly known as the ‘King of tubers’ is one of the major tuber crops grown in India and other parts of the world. Collar rot disease, caused by Sclerotium rolfsii is one of the primary obstacles to tuber cultivation which can significantly reduce yield up to 100%. Saprophytic nature, broad host range, and ability to produce resting structures make it difficult to manage. In this experiment, 10 isolates of S. rolfsii were isolated by the surveying Thiruvananthapuram, Kollam and Alappuzha districts of Kerala, proved the pathogenicity by inoculating the pathogen cultured in sand- maize meal media (9:1). The isolate I3 obtained from Thiruvananthapuram district was found to be the most virulent based on the days taken for symptom development (4 days). Six fungicides (copper oxy chloride (50% WP), mancozeb (75% WP), propiconazole (25% EC), carbendazim (50% WP), trifloxystrobin (25%) + tebuconazole (50%) 75 WG, and carbendazim (12%) + mancozeb (63%) WP @ 50, 100, 250, 500, 1000 and 2000 ppm were evaluated in vitro for their efficacy in inhibiting the fungal mycelial growth and sclerotia formation in isolate I3. All fungicides except carbendazim 50% WP and copper oxy chloride 50% WP, considerably reduced the mycelial development of S. rolfsii. Mancozeb 75%WP and trifloxystrobin (25%) + tebuconazole (50%) 75WG, showed complete inhibition of mycelial growth even at a lower concentration of 50 ppm.

Whole-genome sequence of Sclerotium delphinii, a pathogenic fungus of Dendrobium officinale southern blight

Dendrobium officinale is a rare and precious medicinal plant. Southern blight is a destructive disease in the artificial cultivation of D. officinale, and one of its pathogens is Sclerotium delphinii. S. delphinii is a phytopathogenic fungus with a wide host range with extremely strong pathogenicity. In this study, S. delphinii was isolated from D. officinale with southern blight. Subsequently, this specific strain underwent thorough whole-genome sequencing using the PacBio Sequel II platform, which employed single-molecule real-time (SMRT) technology. Comprehensive annotations were obtained through functional annotation of protein sequences using various publicly available databases. The genome of S. delphinii measures 73.66 Mb, with an N90 contig size of 2,707,110 bp, and it contains 18,506 putative predictive genes. This study represents the first report on the genome size assembly and annotation of S. delphinii, making it the initial species within the Sclerotium genus to undergo whole-genome sequencing, which can provide solid data and a theoretical basis for further research on the pathogenesis, omics of S. delphinii.

Green synthesis of ZnO nanoparticles using Lantana camara leaf extract for the enhancement of plant growth

Abstract Zinc is an important micronutrient for plants, involved in numerous physiological processes as well as numerous enzymatic and metabolic events. Zinc deficiency results in slowed plant development, higher chlorosis rates, smaller leaves, and fewer tillers, which lengthen the crop maturity period and lowers crop quality. In the present study, zinc oxide nanoparticles (ZnONPs) were synthesized through co-precipitation approach by using Lantana camara plant leaf extract. The synthesized ZnONPs were hexagonal in shape with mean size of around 60 nm. The bactericidal activity of ZnONPs was assessed against three phytopathogenic bacterial strains namely Ralstonia solanacearum, Xanthomonas campestris and Erwinia carotovora through broth dilution method. The MIC50 of ZnONPs was 248.33 μg ml−1, 320 .27 μg ml−1 and 320.95 μg ml−1 against R. solanacearum, X. campestris and E. carotovora respectively. The fungiciadal activity of ZnONPs against three phytopathogenic fungal strains was studied by poison food technique. It was observed that 500 ppm ZnONPs could inhbit 86%, 85% and 55% growth of Alterneria solani, Fusarium oxysporum and Athelia rolfsii respectively. The efficacy of ZnONPs as nano fertilizer was evaluated in Solanum lycopersicum Linn. by foliar spray under laboratory condition and it was observed that in comparison with micron sized ZnO, ZnONP treatment could significantly boost up fresh and dry weight, root and shoot length, chlorophyll, lipid and carbohydrate content of the plants.