Banded Leaf Research Articles

Antagonistic potential and biological control mechanisms of Pseudomonas strains against banded leaf and sheath blight disease of maize

Rhizoctonia solani, the causal agent of banded leaf and sheath blight (BL&SB), poses a significant threat to maize and various crops globally. The increasing concerns surrounding the environmental and health impacts of chemical fungicides have encouraged intensified concern in the development of biological control agents (BCAs) as eco-friendly alternatives. In this study, we explored the potential of 22 rhizobacteria strains (AS1–AS22) isolates, recovered from the grasslands of the Pithoragarh region in the Central Himalayas, as effective BCAs against BL&SB disease. Among these strains, two Pseudomonas isolates, AS19 and AS21, exhibited pronounced inhibition of fungal mycelium growth in vitro, with respective inhibition rates of 57.04% and 54.15% in cell cultures and 66.56% and 65.60% in cell-free culture filtrates. Additionally, both strains demonstrated effective suppression of sclerotium growth. The strains AS19 and AS21 were identified as Pseudomonas sp. by 16S rDNA phylogeny and deposited under accession numbers NAIMCC-B-02303 and NAIMCC-B-02304, respectively. Further investigations revealed the mechanisms of action of AS19 and AS21, demonstrating their ability to induce systemic resistance (ISR) and exhibit broad-spectrum antifungal activity against Alternaria triticina, Bipolaris sorokiniana, Rhizoctonia maydis, and Fusarium oxysporum f. sp. lentis. Pot trials demonstrated significant reductions in BL&SB disease incidence (DI) following foliar applications of AS19 and AS21, with reductions ranging from 25 to 38.33% compared to control treatments. Scanning electron microscopy revealed substantial degradation of fungal mycelium by the strains, accompanied by the production of hydrolytic enzymes. These findings suggest the potential of Pseudomonas strains AS19 and AS21 as promising BCAs against BL&SB and other fungal pathogens. However, further field trials are warranted to validate their efficacy under natural conditions and elucidate the specific bacterial metabolites responsible for inducing systemic resistance. This study contributes to the advancement of sustainable disease management strategies and emphasizes the potential of Pseudomonas strains AS19 and AS21 in combating BL&SB and other fungal diseases affecting agricultural crops.

In vitro sensitivity of Rhizoctonia solani f. sp. sasakii causing banded leaf and sheath blight of maize against different fungicides

The laboratory experiment was conducted to evaluate the new fungicide molecules against Rhizoctonia solani f. sp. sasakii by poisoned food technique under in vitro conditions. Out of eleven fungicides tested, the maximum (100%) mycelial inhibition was documented in eight treatments involving both systemic and combi fungicides viz., Carbendazim 50% WP, Propiconazole 25% EC, Tebuconazole 250 EC, Metiram 55% + Pyraclostrobin 5% WG, Fluopyram 17.7% + Tebuconazole 17.7% SC, Iprovalicarb 5.5% + Propineb 61.25%, Carboxin 37.5% + Thiram 37.5% WP and Tebuconazole 50% + Trifloxystrobin 25% WG at all the concentrations tested. Whereas, the least mycelial inhibition was recorded in Pencycuron 250 SC and Dimethomorph 50% WP at 0.05, 0.10 and 0.15 per cent concentrations, respectively.

In vitro inhibition mechanism of Trichoderma asperellum isolates from corn against Rhizoctonia solani causing banded leaf and sheath blight disease and its role in improving the growth of corn seedlings

BackgroundOne of the primary corn diseases, banded leaf and sheath blight, is carried on by the pathogenic fungus Rhizoctonia solani. Efforts to control R. solani are more directed at environmentally friendly control using a biological control agent, such as Trichoderma spp. as antagonistic agents and plant growth promoter. This study aimed to identify T. asperellum isolates based on molecular characteristics and to determine the in vitro inhibition mechanism against R. solani and its role in enhancing the growth of corn seedlings.ResultsThe HMRP7, HMRF7A, HMEDF1B, HMEDF6A, and CHM01 isolates were identified as T. asperellum with a genetic distance coefficient value of 0.000 and a very high similarity of 100%. Meanwhile, the RsHM isolate was identified as R. solani with a homology level of > 90% and genetic distance coefficient values ranging from 0.000 to 0.032. The antagonistic ability showed that the five T. asperellum isolates were able to inhibit the growth of R. solani in vitro on PDA medium with an inhibition percentage of ≥ 50%, so they were categorized as antagonist agents. T. asperellum showed the antagonistic mechanism in inhibiting the R. solani growth through the action of parasitism. The five T. asperellum isolates tested on corn seedlings showed a significantly high difference from the control treatment on the observational variables of maximum growth potential (MGP), growth rate (GtR), growth simultaneity (GS), vigor index (VI), germination rate (GR), and median germination time (T50).ConclusionCHM01 isolate showed better potential than other isolates in inhibiting the growth of R. solani in vitro on PDA medium with a parasitism mechanism and enhancing the growth of corn seedlings.

Alleviation of banded leaf and sheath blight disease incidence in maize by bacterial volatile organic compounds and molecular docking of targeted inhibitors in Rhizoctonia solani.

Rhizoctonia solani (RS) is a pathogenic fungus that affects maize (Zea mays L.) plants and causes banded leaf and sheath blight (BLSB) with severe consequences leading to significant economic losses. Contrarily, rhizobacteria produce numerous volatile organic compounds (VOCs) that help in devising the environment-friendly mechanism for promoting plant growth and stress alleviation without having physical contact with plants. In the present study, 15 rhizobacterial strains were tested for their antagonism against RS. The antagonistic potential of VOCs of the tested plant growth-promoting rhizobacteria (PGPR) strains ranged from 50% to 80% as compared to the control (without PGPR). Among these 15 strains, the maximum (80%) antagonistic activity was exhibited by Pseudomonas pseudoalcaligenes SRM-16. Thus, the potential of VOCs produced by P. pseudoalcaligenes SRM-16 to alleviate the BLSB disease in maize was evaluated. A pot experiment was conducted under greenhouse conditions to observe the effect of VOCs on disease resistance of BLSB-infected seedlings. Overall, maize seedlings exposed to VOCs showed a significant increase in disease resistance as indicated by a reduced disease score than that of unexposed infected plants. The VOCs-exposed maize exhibited lower (11.6%) disease incidence compared to the non-inoculated maize (14.1%). Moreover, plants exposed to VOCs displayed visible improvements in biomass, photosynthetic pigments, osmoregulation, and plant antioxidant and defense enzyme activities compared to the healthy but unexposed seedlings. Simultaneous application of RS and VOCs enhanced superoxide dismutase (SOD), peroxidase (POD), catalase (CAT), phenylalanine ammonia lyase (PAL), ascorbate peroxidase (APX), and polyphenol oxidase (PPO) activities by 96.7%, 266.6%, 313.7%, 246.6%, 307%, and 149.7%, respectively, in the roots and by 81.6%, 246.4%, 269.5%, 269.6%, 329%, and 137.6%, respectively, in the shoots, relative to those of the control plants. The binding affinity of the VOCs (2-pentylfuran, 2,3-butanediol, and dimethyl disulfide) with CRZ1 and S9 protein receptors of RS was assessed by deploying in silico methods. Overall, 2-pentylfuran exhibited a binding affinity with both the selected receptors of RS, while 2,3-butanediol and dimethyl disulfide were able to bind S9 protein only. Hence, it can be deduced that S9 protein receptors are more likely the target RS receptors of bacterial VOCs to inhibit the proliferation of RS.

Tackling banded leaf and sheath blight disease of maize through activation of host defense

Maize or corn (Zea mays L.) is the third most important cereal crop in the economy of agriculture. Banded leaf and sheath blight (BLSB) caused by Rhizoctonia solani (= R. solani f. sp. sasakii) is one of the highly devastating soil-borne diseases of maize in South and Southeast Asia. Although the use of resistant varieties is preferred as an eco-friendly and cheapest approach to disease management, unfortunately, no true genetic sources of BLSB resistance are available in maize. Hence, chemically induced resistance in the host plant is considered an alternative strategy against many crop diseases. The present study investigated the basis of BLSB resistance in maize hybrid variety Vivek QPM-9 by seed priming with two plant defense inducers, viz., salicylic acid (SA) and jasmonic acid (JA). Higher concentrations (100 ppm) of SA and JA were significantly more effective against R. solani than the lower concentrations (75 and 50 ppm) in vitro. The study found that the application of SA and JA as exogenous pretreatment resulted in improved seed germination, increased seedling weight, and enhanced overall plant growth. During the Kharif season (June–October) in both 2020 and 2021, under in vivo conditions in a net house, the application of SA at 100 and 75 ppm and JA at 100 ppm resulted in a significant decrease in the percent disease index (PDI) of 46.79%, 47.05%, and 48.85%, respectively. Both plant defense inducers elevated the activity of the enzymes superoxide dismutase (SOD), catalase (CAT), and phenylalanine ammonia-lyase (PAL) in maize at higher concentrations of 100 ppm. Seed priming with a high concentration of the inducers was more effective in suppressing the disease and increasing grain yield under the controlled condition of the net house. The study shows the scope of using need-based fungicides with a reduced amount in the management of fungal diseases of maize by adopting a plant defense inducer-mediated host resistance approach.

Alternative management practices for the control of banded leaf and sheath blight incited by Rhizoctonia solani f.sp. sasakii (Kuhn) Exner in maize in North Western India

Alternative management practices for the control of banded leaf and sheath blight incited by Rhizoctonia solani f.sp. sasakii (Kuhn) Exner in maize in North Western India

Identification of resistant sources and evaluation of biocontrol agents for suppression of banded leaf and sheath blight in little millet (Panicum sumatrense)

Identification of resistant sources and evaluation of biocontrol agents for suppression of banded leaf and sheath blight in little millet (Panicum sumatrense)

Integrated disease management of banded leaf and sheath blight caused by Rhizoctonia solani in proso millet

Integrated disease management of banded leaf and sheath blight caused by Rhizoctonia solani in proso millet

Evaluation of Maize Genotypes against Banded Leaf and Sheath Blight Incited by Rhizoctonia solani f. sp. sasakii Exner (Cantharellales: Ceratobasidiaceae) Under Artificial Epiphytotic Conditions, India

Zea mays L. (Poales) is one of the most important cereal crops belongs to Poaceae family with very high potential for yield. Production of maize is hampered by a major constraint and devastating disease banded leaf and sheath blight caused by Rhizoctonia solani f. sp. sasakii. The experiment was conducted to evaluate the maize genotypes under field conditions at CCS Haryana Agricultural University, Regional Research Station, Karnal (India). A set of fifty seven genotypes (hybrids/inbred lines) were screened against banded leaf and sheath blight during kharif 2020 and 2021 under artificial epiphytotic conditions. The severity of banded leaf and sheath blight was recorded following 1-9 scale and genotypes evaluated categorized into four groups viz., resistant, moderately resistant, moderately susceptible and susceptible based on their disease reaction. Out of fifty seven genotypes screened against BLSB, eight inbred lines viz., HKI 161, HKI-163, HKI-193-2, HKI-288-2, HKI-295, HKI-488, HKI-1344 and HKI 1352 (58-9-2)-2 found resistant and seventeen maize inbred lines were moderately resistant, whereas two hybrids (HQPM-4 and HKI-1040-7 x HKI 659-3) showed resistant reaction and ten maize hybrids were moderately resistant. Thus, these resistant/ moderately resistant maize genotypes can be further use in maize breeding program to develop durable BLSB resistant varieties.

Virulence Spectrum among Rhizoctonia solani f. sp. sasakii Isolates from Multi-Geographical Locations of India

Rhizoctonia solani f. sp. sasakii (RSS) is a highly devastating soil-borne fungal pathogen inciting banded leaf and sheath blight (BLSB) disease in maize. In India, annually one percent of the total maize yield is reduced by BLSB. Due to continuous occurrence and wide spread of disease, the present experiment was conducted to assess the pathogenic variability among different isolates obtained from multi-geographical locations of India. Pathogenic behaviour of each isolates was predicted through the comparable study of their incubation period, average disease score and disease intensity on the three maize hybrids (Normal maize- HM 8, QPM maize- QPM 9 and sweet corn- HSC I). The incubation period of all the R. solani isolates ranged from 3 to 7 days with average disease score ranged from 2.1 to 7.1depending upon the host and isolate interaction after artificial inoculation. Disease intensity of all the RSS isolates on maize hybrids varied from 8.1 to 52.1% while isolates RSS 29 (New Delhi) and RSS 1 (Karnal) were found highly virulent, in comparison to other forty nine RSS isolates. As these isolates were highly virulent on maize hybrids with average disease score ranged from 6.2 to 7.1, whereas the isolates RS 30 (Dholi) and RS 31 (Dhaula Kuan) were recorded as least virulent, showed resistant disease reaction with average disease score ranged from 1.5 to 2.4.

Field efficacy of phytoextracts, antagonists and chemical fungicides with native approach for controlling banded leaf and sheath blight in maize

Experiments on maize (Zea mays L.) were carried out aiming to control banded leaf and sheath blight (BLSB) caused by fungus, Rhizoctonia solani Kuhn with six treatments represented by different fungicides, antagonists and phytoextracts against control receiving no spray with three replicates of each under field conditions during two consecutive years from 2019 to 2020. In 2019, the higher Percent Disease Control (44.85%) and Percent Yield Increase (62.10%) both were estimated in plot treated with SAAF (carbendazim 12% WP + mancozeb 63% WP) followed by the plot where seed was treated with bavistin (carbendazim 50% WP). The grain yield was higher in plots treated with SAAF followed by leaf stripping method. Almost similar trends of disease control were observed in 2020. The lower percent disease index (47.67% PDI) with higher yield (4660 kg/ha) was recorded from the plot sprayed with SAAF@3 g/L during knee high and subsequent spray after 15 days interval followed by leaf stripping technique (lower 3-4 leaves from ground surface) as compared to control plot (PDI- 93.67% and yield-1393.33 kg/ ha). The results showed that, the combined treatment with fungicides i.e. seed treatment with bavistin before sowing and twice spraying of SAAF during knee height stage at 15 days interval followed by leaf stripping technique were effective to control banded leaf and sheath blight disease of maize to increase the yield.

Field Efficacy of Cowpathy Products and Biological Control Agents in Controlling Banded Leaf and Sheath Blight Disease and Increasing Maize Yield

Background: Maize is an important cereal crops as it is a good source of nutrition and raw material for industries. Among various pathogens attacking maize crop, banded leaf and sheath blight (BLSB) caused by Rhizoctonia solani f.sp sasakii is a potential threat for quality maize production. It affects all the plant parts at every stage of crop growth. Methods: The present investigation was carried out at Regional Research Station Uchani, Karnal of CCS Haryana Agricultural University, Hisar to evaluate the efficiency and efficacy of biorational products (Cowpathy) such as Vedic Krishi inputs viz., Beejamrit and Jiwamrit, compost extract and biocontrol agents with the objective to manage banded leaf and sheath disease and increasing yield of maize. Result: All the biorational products were found quite effective in controlling the disease and enhancing the yield attributes. Seed treatment with Achook (Neem based fungicide containing azadirachtin) @ 2 g/l of seed was found most effective in controlling disease upto 51.77 per cent. Seed treatment with Pseudomonas fluorescens @ 10 ml/kg followed by Beejamrit @ 10 ml/kg were also found effective in reducing the disease incidence as compared to control. These are economic, reliable and viable sources and hold good promise for use in organic and sustainable agriculture.

Biochemical changes induced in the maize leaf sheath upon inoculation with Rhizoctonia solani incitant of banded leaf and sheath blight

Biochemical changes induced in the maize leaf sheath upon inoculation with Rhizoctonia solani incitant of banded leaf and sheath blight

Multiple modules for the management of banded leaf and sheath blight of maize in India

Multiple modules for the management of banded leaf and sheath blight of maize in India

Ecofriendly alternative for sustainable management of banded leaf and sheath blight of maize (Zea mays)

Banded leaf and sheath blight (BLSB) of maize (Zea mays L.) caused by Rhizoctonia solani f. sp. sasakii is one of the most important yield-limiting factors faced by growers in India. Therefore, attempts were made to identify promising suitable bioagents for the management of BLSB of maize. Present study was carried out to check the efficacy of two bioformulations, viz. Pusa Th3 (Trichoderma harzianum) and Pusa Cg2 (Chaetomium globosum) against BLSB in the Vivek QPM-9 cultivar under field conditions during kharif 2018 and 2019 using seven different treatments. All the treatments significantly reduced the disease incidence and contributed higher yield of maize as compared to positive control. The lowest per cent disease index (37.87 and 53.17%) was recorded in case of both seedtreatment and foliar spray with T. harzianum. It gave 40.39% disease control and also increased the yield up to 28.47% over unprotected plot. It was concluded that BLSB disease can be managed by seed treatment with T. harzianum @2 g/kg seed, followed by one spray of T. harzianum @0.1% at 30 days after sowing. Sustainable ecofriendly disease management options identified in the study can help maize growers not only in safeguarding the crop but also increase cost: benefit ratio. In addition, the results indicated that bio formulation of Pusa Th3 can be used to substitute chemical fungicides especially in controlling BLSB

Deep learning-based approach for identification of diseases of maize crop

In recent years, deep learning techniques have shown impressive performance in the field of identification of diseases of crops using digital images. In this work, a deep learning approach for identification of in-field diseased images of maize crop has been proposed. The images were captured from experimental fields of ICAR-IIMR, Ludhiana, India, targeted to three important diseases viz. Maydis Leaf Blight, Turcicum Leaf Blight and Banded Leaf and Sheath Blight in a non-destructive manner with varied backgrounds using digital cameras and smartphones. In order to solve the problem of class imbalance, artificial images were generated by rotation enhancement and brightness enhancement methods. In this study, three different architectures based on the framework of ‘Inception-v3’ network were trained with the collected diseased images of maize using baseline training approach. The best-performed model achieved an overall classification accuracy of 95.99% with average recall of 95.96% on the separate test dataset. Furthermore, we compared the performance of the best-performing model with some pre-trained state-of-the-art models and presented the comparative results in this manuscript. The results reported that best-performing model performed quite better than the pre-trained models. This demonstrates the applicability of baseline training approach of the proposed model for better feature extraction and learning. Overall performance analysis suggested that the best-performed model is efficient in recognizing diseases of maize from in-field images even with varied backgrounds.

First report of Rhizoctonia solani causing Banded leaf and sheath blight disease in Sugarcane (Saccharum officinarum) from Ghazipur district of Uttar Pradesh, India

During August 2016, banded leaf and sheath blight symptoms were observed on sugarcane (cv. BO-91) in the Village Bhawanipur of Ghazipur district of Uttar Pradesh (India). A survey was done to assess the prevalence of and collect the specimens of banded leaf and sheath blight disease from sugarcane fields in the Ghazipur district during 2016–17. A total of 15 fungal isolates were collected from different parts of the district and pathogenicity testing of these isolates was done following Koch postulates. All the 15 isolates were able to produce disease in the controlled laboratory conditions as well as in the field. Further, these isolates were morphologically characterized as Rhizoctonia solani. To confirm the identity at molecular level, ITS sequencing of two most virulent isolates was done. Based on the ITS sequence similarity, these two isolates, viz. SCRS-2018-1A and SCRS-2018-1B were identified as R. solani. As per the existing records and our knowledge based on the extensive survey of pertinent literature, this is the first report of R. solani causing banded leaf and sheath blight disease in Sugarcane from Ghazipur district of Uttar Pradesh, India.

Anastomosis groups and pathogenicity of Rhizoctonia isolates causing banded leaf and sheath blight on maize in Shanxi province of China

Anastomosis groups and pathogenicity of Rhizoctonia isolates causing banded leaf and sheath blight on maize in Shanxi province of China

Genetic diversity and virulence spectrum of Rhizoctonia solani, the incitant of banded leaf and sheath blight of maize

AbstractBanded leaf and sheath blight (BLSB) of maize caused by Rhizoctonia solani is one of the most important yield‐limiting factors faced by growers in India. The pathogen is known to be highly diverse, and several species are known to cause BLSB. In the current study, forty‐four isolates of R. solani associated with maize were collected from different agro‐ecological zones of Punjab, a north Indian state. These were characterized genetically and phenotypically and for their virulence behaviour. Using internal transcribed spacer (ITS)‐based species‐specific markers, we confirmed the association of two species viz., solani (100%) and oryzae‐sativae (18.18%) with BLSB with later being detected in mixed infection. All the isolates belonged to anastomosis group AG1‐IA with a typical amplicon size of 265 bp. Genetic variation in the associated Rhizoctonia sp. was analysed using 27 inter simple sequence repeats (ISSR) markers which revealed high degree of polymorphism (PIC value ranging from 0.819 to 0.921) and clustered the Rhizoctonia population into two major groups. Based on fungal morphology, the hierarchical cluster analysis placed 44 Rhizoctonia isolates into six major groups (M1–M6). The virulence of each isolate studied on four hybrids and seven inbred maize lines revealed that maize hybrid JH3459 and inbred LMDR‐2 were less susceptible to Punjab population of Rhizoctonia species. Partial correlation was also obtained between genetic diversity, pathological variation and geographical origins of isolates. This is the first attempt to study the diversity of Rhizoctonia sp. associated with banded leaf and sheath blight of maize in Punjab state.

Identification of virulence associated milRNAs and their bidirectional targets in Rhizoctonia solani and maize during infection

BackgroundAnastomosis group 1 IA (AG1-IA) of Rhizoctonia solani is the major agent of banded leaf and sheath blight (BLSB) disease that causes severe yield loss in many worldwide crops. MicroRNAs (miRNAs) are ~ 22 nt non-coding RNAs that negatively regulate gene expression levels by mRNA degradation or translation inhibition. A better understanding of miRNA function during AG1-IA infection can expedite to elucidate the molecular mechanisms of fungi-host interactions.ResultsIn this study, we sequenced three small RNA libraries obtained from the mycelium of AG1-IA isolate, non-infected maize sheath and mixed maize sheath 3 days after inoculation. In total, 137 conserved and 34 novel microRNA-like small RNAs (milRNAs) were identified from the pathogen. Among these, one novel and 17 conserved milRNAs were identified as potential virulence-associated (VA) milRNAs. Subsequently, the prediction of target genes for these milRNAs was performed in both AG1-IA and maize, while functional annotation of these targets suggested a link to pathogenesis-related biological processes. Further, expression patterns of these virulence-associated milRNAs demonstrated that theyparticipate in the virulence of AG1-IA. Finally, regulation of one maize targeting gene, GRMZM2G412674 for Rhi-milRNA-9829-5p, was validated by dual-luciferase assay and identified to play a positive role in BLSB resistance in two maize mutants. These results suggest the global differentially expressed milRNAs of R. solani AG1-IA that participate in the regulation of target genes in both AG1-IA and maize to reinforce its pathogenicity.ConclusionsOur data have provided a comprehensive overview of the VA-milRNAs of R. solani and identified that they are probably the virulence factors by directly interfered in host targeting genes. These results offer new insights on the molecular mechanisms of R.solani-maize interactions during the process of infection.