Spot Blotch Disease Of Wheat Research Articles

Assessment of Some Culture Media for Optimum Growth and Sporulation of Bipolaris sorokiniana Causing Spot Blotch of Wheat

An experiment was conducted during January–June, 2022 at Department of Plant Pathology, Uttar Banga Krishi Viswavidyalaya for the evaluation of the different culture media on the growth of the fungus Bipolaris sorokiniana causing spot blotch disease in wheat. Five different growth media, viz., Potato Dextrose Agar (PDA), wheat seed extract+PDA (WSPDA), wheat leaf decoction+PDA (WLPDA), carrot juice extract+PDA (CPDA), and oatmeal agar (OMA), were used in the experiment. PDA supplemented with different plant extracts exhibited differential growth and sporulation patterns on B. sorokiniana. The maximum colony diameter of 8.09 mm at 9 days after inoculation demonstrated that the OMA provided the best growth conditions. Moreover, based on the Tukey HSD test, the AUGPC of OMA was found to be the highest (34.68±1.3 cm2) and significantly different from all the other media used in the study. The OMA was followed by the WLPDA, which had an AUGPC of 22.6±1.79 cm2. The fungus sporulated in all the media considered for the present study, with OMA recording the highest sporulation with 44×104 spores ml-1, followed by WLPDA with 41×104 spores ml-1. The lowest level of sporulation was seen in CPDA, with a concentration of 15×103 spores ml-1. Based on the aforementioned results, it can be inferred that oatmeal agar was the most suitable medium for the development and sporulation of B. sorokiniana, followed by a mixture of wheat leaf decoction and PDA. On the other hand, PDA alone and carrot juice PDA were shown to be the least suitable media.

Green Synthesis of Zinc Oxide Nanoparticles, Characterization and Its Applications in Inducing Disease Resistance Against Spot Blotch Disease in Wheat by Enhancing Its Physiological and Biochemical Parameters

Green Synthesis of Zinc Oxide Nanoparticles, Characterization and Its Applications in Inducing Disease Resistance Against Spot Blotch Disease in Wheat by Enhancing Its Physiological and Biochemical Parameters

Survey, isolation and characterisation of Bipolaris sorokiniana (Shoem.) causing spot blotch disease in wheat under the climatic conditions of the Indo–Gangetic plains of India

Wheat spot blotch has emerged as a disease of significant concern in recent years. The pathogen Bipolaris sorokiniana can infect stems, leaves, roots and seeds, increasing its impact. The pathogen is particularly prevalent in the wheat growing zone of West Bengal, which provides congenial conditions for the growth and development of the pathogen. However, its knowledge under West Bengal conditions is inadequate. To address this issue, isolates of Bipolaris sorokiniana were collected from different locations in West Bengal. The pathogenic species were identified via comprehensive morphological studies supplemented with internal transcribed spacer (ITS)-rDNA sequence analysis and pathogenicity. The disease severity of the twelve isolates collected varied among the surveyed locations, ranging from 44.03% to 81.48 %. The greatest radial growth was observed in BSC11 (50.07 mm), whereas the lowest growth was recorded in BSC9 (6.47 mm) at 96 h after inoculation. Molecular studies confirmed that the isolates were Bipolaris sorokiniana. In pathogenicity assays, BSC11 presented the highest area under the disease progress curve (AUDPC) (380.05) and percent disease index (PDI) among the isolates at 20 dai (38.33 %). The correlation matrix revealed that disease severity was positively correlated with the number of spores (r2 = 0.70), growth rate of mycelia (r2 = 0.77), and lesion size (r2 = 0.74), whereas the length of the spores, incubation period, and latent period were negatively and significantly correlated with disease severity. Establishing the aggressiveness of a pathogen is pivotal in studying host‒ interactions. Our study established BSC11 as a highly virulent pathogen isolate that can be used further for comprehensive analysis of wheat‒Bipolaris sorokiniana interactions.

Genome-wide association study of lignin trait in elite spring wheat against spot blotch disease

Spot blotch disease in wheat is one of major yield-limiting factor in warm humid conditions of South Asia. Developing the disease-resistant variety through molecular methods is an economically and environmentally eco-friendly approach. Diseased wheat leaves associated with lignin content increased by two or three times at 72 h compared with control. The genomic region associated with lignin content was investigated in a set of 289 diverse spring wheat genotypes. The genome - wide association studies panel employed a 90K Illumina SNP array and phenotyped in four environments. The GWAS analysis showed a total of 86 marker-trait associations on 1A, 1B, 2A, 2B, 2D, 3A, 3D, 4A, 5A, 5B, 6A, 6D, 7A, 7B, 7D were linked lignin trait. Insilco analysis revealed that significant SNPs were located on import putative candidate genes thirteen in the Transmembrane domain of the protein-kinase family and were involved in the host-pathogen interaction. The identified significant MTAs for further validation and useful for the wheat breeding programs to develop the spot blotch disease resistance.

Investigating the interaction between some of Bipolaris sorokiniana’s toxins and the Gα Subunit of the Wheat G-Protein using bioinformatics tools

Spot blotch disease of wheat, caused by the fungus Bipolaris sorokiniana (Sacc.) Shoem., produces several toxins like: prehelminthosporol, helminthosporol, helminthosporic acid, sorokinianin, Bipolaroxin. These toxins interact with the plant and thereby increase the symptoms of small dark lesions and huge yield losses in different regions around the world so there is an urgent need to decipher the molecular interaction between wheat and those toxins for in-depth understanding of host–pathogen interactions. In the present study, we have modeledthe three-dimensional structure of G-protein alpha subunit from Triticum aestivum as G-protein was shown that it is an important player behind the resistance to many plant diseases. Molecular docking studies were performed using the active site of the modeled G-protein alpha subunit from T. aestivumand some of fungus’s toxins followed by molecular dynamics (MD) simulation studies to explore the stability, conformational flexibility, and dynamic behavior. Protein-ligand interaction study revealed one H-bond formed by Lys302 and hydrophobic contacts formed by Tyr159, Gly162, Val167, Asp256, Gln257 and Ile298 with prehelminthosporol, Protein-ligand interaction study revealed H-bond formed three H-bonds formed by Tyr159, Gly162, and Asp256 and hydrophobic interactions formed by Ser160, Cys161, Ser162, Ile298, Lys302 and Val306 with helminthosporic acid. Protein-ligand interaction study revealed two H-bond formed by His172, Arg301 and hydrophobic interactions by Tyr159, Pro168, Asp169, Ile298 and Lys302 with sorokinianin. Protein-ligand interaction study revealed H-bond formed six H-bonds mainly formed by Glu29, Ser30, Lys32, and Ala177. In addition to H-bonds, hydrophobic contacts formed by Gly28, Gly31, Ser33, Thr34, Arg78, Val179, Thr181 and Gly209 with Bipolaroxin were also observed.

Defense Inducer Compounds Up-regulated the Peroxidase, Polyphenol Oxidase, and Total Phenol Activities against Spot Blotch Disease of Wheat.

Spot blotch disease of wheat caused by Bipolaris sorokiniana (Sacc.) Shoem is considered as an economically important disease which affects all the growing stages of wheat crop. Therefore, it is important to search some effective management strategies against the spot blotch pathogen. Some synthetic elicitor compounds (salicylic acid, isonicotinic acid, and chitosan) and nano-particles (silver and aluminum) were tested against the pathogen to observe the change in biochemical activity and defense action of wheat plant against spot blotch disease. All the tested elicitor compounds and nano-particles showed a significant increase in activity of peroxidase, polyphenol oxidase (PPO), and total phenol over control. The highest increase in activity of peroxidase was recorded at 72 h from chitosan at 2 mM and 96 h from silver nano-particle at 100 ppm. Maximum PPO and total phenol activity were recorded from chitosan at 2 mM and silver nano-particle at 100 ppm as compared to pathogen-treated and healthy control. The lowest percent disease index, lowest no. of spots/leaf, and no. of infected leaves/plant were found in silver nano-particle at 100 ppm and chitosan at 2 mM, respectively. The use of defense inducer compounds results in significantly up-regulated enzymatic activity and reduced spot blotch disease. Therefore, chitosan and silver nano-particle could be used as alternative methods for the management of spot blotch disease.

Managing spot blotch disease in wheat: Conventional to molecular aspects.

Spot blotch (SB) caused by Bipolaris sorokiniana (teleomorph Cochliobolus sativus) is one of the devastating diseases of wheat in the warm and humid growing areas around the world. B. sorokiniana can infect leaves, stem, roots, rachis and seeds, and is able to produce toxins like helminthosporol and sorokinianin. No wheat variety is immune to SB; hence, an integrated disease management strategy is indispensable in disease prone areas. A range of fungicides, especially the triazole group, have shown good effects in reducing the disease, and crop-rotation, tillage and early sowing are among the favorable cultural management methods. Resistance is mostly quantitative, being governed by QTLs with minor effects, mapped on all the wheat chromosomes. Only four QTLs with major effects have been designated as Sb1 through Sb4. Despite, marker assisted breeding for SB resistance in wheat is scarce. Better understanding of wheat genome assemblies, functional genomics and cloning of resistance genes will further accelerate breeding for SB resistance in wheat.

Trichoderma harzianum sensu lato TSM39: A wheat microbiome fungus that mitigates spot blotch disease of wheat (Triticum turgidum L. subsp. durum) caused by Bipolaris sorokiniana

Bipolaris sorokiniana - the causal agent of wheat spot blotch - is an emerging phytopathogenic fungus in the Yaqui Valley, Sonora, Mexico. At present, its control relies on the use of harmful chemicals, partly due to the lack of effective alternatives. Thus, this work aimed to identify and characterize indigenous wheat-associated fungal strains with biocontrol capacity against B. sorokiniana that can be integrated into control strategies for spot blotch management. Out of 59 fungal strains evaluated, we identified 5 strains with antagonistic activity against B. sorokiniana by dual confrontation assay, and these were taxonomically assigned as Trichoderma harzianum sensu lato (strains TSM39 and TSO39), Aspergillus terreus (strains TRQ89 and TRQ93), and Aspergillus nidulans (strain TRQ83) based on phylogenetic analysis using the ITS region of the rRNA cistron. Trichoderma harzianum TSM39 showed interesting biological control traits (i.e., strong antagonistic activity, high growth rate, non-cytotoxicity) and its application to wheat plants - under highly conducive conditions for spot blotch outbreak- resulted in a significant reduction of disease severity. In vitro experiments revealed that the chitinolytic system of strain TSM39 responds to B. sorokiniana lysates (signals), which could have potential biotechnological applications to improve its biocontrol activity. Additionally, a solid-state fermentation system was successfully established for spore production of strain TSM39. Taken together, Trichoderma harzianum sensu lato TSM39 is a biocontrol agent against B. sorokiniana with the potential to be integrated into spot blotch management strategies and contribute to the sustainability of the region.

Novel Insights into Understanding the Molecular Dialogues between Bipolaroxin and the Gα and Gβ Subunits of the Wheat Heterotrimeric G-Protein during Host-Pathogen Interaction.

Spot blotch disease of wheat, caused by the fungus Bipolaris sorokiniana (Sacc.) Shoem., produces several toxins which interact with the plants and thereby increase the blightening of the wheat leaves, and Bipolaroxin is one of them. There is an urgent need to decipher the molecular interaction between wheat and the toxin Bipolaroxin for in-depth understanding of host–pathogen interactions. In the present study, we have developed the three-dimensional structure of G-protein alpha subunit from Triticum aestivum. Molecular docking studies were performed using the active site of the modeled G-protein alpha and cryo-EM structure of beta subunit from T. aestivum and ‘Bipolaroxin’. The study of protein–ligand interactions revealed that six H-bonds are mainly formed by Glu29, Ser30, Lys32, and Ala177 of G-alpha with Bipolaroxin. In the beta subunit, the residues of the core beta strand domain participate in the ligand interaction where Lys256, Phe306, and Leu352 formed seven H-bonds with the ligand Bipolaroxin. All-atoms molecular dynamics (MD) simulation studies were conducted for G-alpha and -beta subunit and Bipolaroxin complexes to explore the stability, conformational flexibility, and dynamic behavior of the complex system. In planta studies clearly indicated that application of Bipolaroxin significantly impacted the physio-biochemical pathways in wheat and led to the blightening of leaves in susceptible cultivars as compared to resistant ones. Further, it interacted with the Gα and Gβ subunits of G-protein, phenylpropanoid, and MAPK pathways, which is clearly supported by the qPCR results. This study gives deeper insights into understanding the molecular dialogues between Bipolaroxin and the Gα and Gβ subunits of the wheat heterotrimeric G-protein during host–pathogen interaction.

Effect of Date of Sowing and Nitrogen Levels on Spot Blotch Disease of Wheat Caused by Bipolaris sorokiniana

In India, wheat is grown in the Rabi season mostly under irrigated condition. The main constraints responsible for less yield of wheat in comparison to other country seem to non-availability of seeds of improved high yielding varieties to farmers, poor fertility, unirrigated land and other inputs. Experimental findings clearly indicates that yield loss due to spot blotch varied between 7 to 30 per cent and loss in 1000-grain weight between 3 to 23 per cent, depending upon the levels of disease. Delayed sowing favored incidence of spot blotch irrespective of nitrogen level and more disease developed at higher nitrogen level in all the three date of sowing. Higher levels of nitrogen at all the three date of sowing increased yield and 1000-grain weight and with delay in sowing, yield and 1000-grain weight decreased significantly at all the three nitrogen level.

Spot blotch disease of wheat as influenced by foliar trichome and stomata density

Spot blotch, caused by Bipolaris sorokiniana, is a potent biotic constraint to wheat crop leading to substantial yield abatement in warm humid South Asia (e.g. India, Nepal and Bangladesh) and other major wheat-growing countries such as Canada, the United States, Brazil and Australia. A set of 98 bread wheat genotypes were evaluated over two growing seasons to investigate the relationship among foliar trichome, stomata density, and susceptibility to the spot blotch pathogen. The higher density of trichomes (90-140 mm −2 ) on the adaxial surface of flag leaves entrapped 32-74 mm −2 pathogen spores. It restricted the dew droplets size (0.15–0.3 mm 2 ) on the flag leaves and thus prevented direct contact between the spores and the leaf epidermis. Trichome density was negatively associated with the disease development and spore germination but positively associated with grain size and the number of spores entrapped on trichomes per mm 2 . Conversely, stomata density was positively associated with the development of the disease. Cluster and principal component analyses divided trichome density, the number of spores trapped on trichome per mm 2 , and thousand grain weight into one group and stomata density, the area under disease progress curve, percent spore germination, and dew scale into another group. The results from this study provided a novel insight to breeders where the selection of bread wheat genotypes with high trichome (90-140 mm −2 ) and low stomata density (72-90 mm −2 ) on foliage could enhance spot blotch resistance in wheat. • Spot blotch of wheat reduces up to 30% yield in the Indian subcontinent. • The relationship among foliar trichome, stomata density, and susceptibility to the spot blotch pathogen was studied. • The higher density of trichomes (90-140 mm −2 ) entrapped 32-74 mm −2 spores prevented direct contact between the spores and the leaf epidermis. • This study assists breeders for the selection of bread wheat genotypes with high trichomes and low stomata density on foliage could enhance spot blotch resistance.

Functional analysis of SCD1 gene involved in pathogenicity of spot blotch disease of wheat causing fungus Bipolaris sorokiniana

Functional analysis of SCD1 gene involved in pathogenicity of spot blotch disease of wheat causing fungus Bipolaris sorokiniana

Integrated omics approaches for deciphering antifungal metabolites produced by a novel Bacillus species, B. cabrialesii TE3T, against the spot blotch disease of wheat (Triticum turgidum L. subsp. durum)

Bipolaris sorokiniana is an important biotic constraint for global wheat production, causing spot blotch disease. In this work, we present a comprehensive characterization of the cell-free culture filtrate (CF) and precipitated fraction (PF) of Bacillus cabrialesii TE3T showing an effective inhibition of spot blotch. Our results indicated that CF produced by B. cabrialesii TE3T inhibits the growth of B. sorokiniana through stable metabolites (after autoclaving and proteinase K treatment). Antifungal metabolites in CF and PF were explored by an integrated genomic-metabolomic approach. Genome-mining revealed that strain TE3T contains the biosynthetic potential to produce wide spectrum antifungal (surfactin, fengycin, and rhizocticin A) and antibacterial metabolites (bacillaene, bacilysin, bacillibactin, and subtilosin A), and through bioactivity-guided LC-ESI-MS/MS approach we determined that a lipopeptide complex of surfactin and fengycin homologs was responsible for antifungal activity exhibited by B. cabrialesii TE3T against the studied phytopathogen. In addition, our results demonstrate that i) a lipopeptide complex inhibits B. sorokiniana by disrupting its cytoplasmatic membrane and ii) reduced spot blotch disease by 93 %. These findings show the potential application of metabolites produced by strain TE3T against B. sorokiniana and provide the first insight into antifungal metabolites produced by the novel Bacillus species, Bacillus cabrialesii.

Screening of wheat genotypes against foliar blight pathogens under artificial inoculation conditions

Foliar blight disease caused by Bipolaris sorokiniana (Sacc.) Shoem is most important disease of wheat in North Eastern plain zones (NEPZ) representing warm and humid climate in India. It is also increasing in North Western plains zones (NWPZ), due to climate changes and causes considerable losses in susceptible varieties. A field study was conducted during Rabi, 2016-17 crop seasons at Main Experiment Station, Narendradev University of Agriculture and Technology, Kumarganj, Faizabad to test the resistance of 150 genotypes against Bipolaris sorokiniana under artificial epiphytotics conditions. Each genotype was sown in last week of November in single row of one meter length. Variety Raj 4015 was used as check and was sown after every 20 genotypes. Pure culture of Bipolaris sorokiniana was inoculated on genotypes by using cleaned sprayer, at evening. Disease data was recorded using double digit scale based on per cent blighted area on flag leaf and one leaf just below. Out of 150 genotypes, no any genotype found immune, 9 genotypes were found resistant, 66 were moderately resistant, 69 were moderately susceptible and 5 were found susceptible and no any genotype found high susceptible against spot blotch disease of wheat.

Management of spot blotch disease of wheat in Eastern Uttar Pradesh

Management of spot blotch disease of wheat in Eastern Uttar Pradesh

In-vitro evaluation of botanicals and fungicides against Bipolaris sorokiniana, causing spot blotch of wheat

Spot blotch disease of wheat caused by Bipolaris sorokiniana; is one of the most concerning disease in warm and humid regions of Nepal due to its widespread prevalence and increasing severity. An in-vitro experiment was conducted to evaluate the efficacy of different botanicals and fungicides against Bipolaris sorokiniana, in National Plant Pathology Research Centre’s laboratory at Khumaltar, Lalitpur in 2019. The experiment was done in completely randomized design with three replications by poison food technique. Five botanicals viz. neem, garlic, eucalyptus, bojho and asuro at three different concentrations (5%, 10% and 15%) and eight fungicides viz. sectin, curex, bavistin, vacomil plus, saaf, sajha, criptan and tilt at three concentration levels (25 ppm, 50 ppm and 100 ppm) except curex (50 ppm, 100 ppm and 200 ppm) were used to evaluate the effect on the radial mycelial growth and mycelial growth inhibition percentage of the pathogen. The different botanical extracts and fungicides in different concentrations inhibited the mycelial growth of fungus significantly (p<0.01). The highest mycelial growth inhibition percentage was found by the application of garlic clove extract (52.85%) at 15% which was followed by bojho (52.48%) at 15% concentration. While tilt was found effective fungicide which completely inhibits the mycelial growth at all concentrations. Also, fungicides viz. sajha (79.78%), saaf (73.59%) and sectin (70%), at 100 ppm were found effective in controlling the pathogen as compare to others. Mycelial growth inhibition of the fungus was found to be increased with the increase in concentrations of botanicals and fungicides.

Efficacy of chemical fungicides against spot blotch (Bipolaris sorokiniana) disease management of wheat in northern part of West Bengal

The spot blotch disease caused by Bipolaris sorokiniana (Sacc.) Shoem is one of the most important foliage disease of wheat crop. This disease appears in almost all wheat growing areas of the world. In Northern part of west Bengal this disease causes severe yield loss every year. For the management of spot blotch disease of wheat five chemical fungicides was used. Plant disease intensity decreased with the application of different treatment over untreated control.The lowest AUDPC was recorded in T4 (Propiconazole@ 1ml/l)260.8 followed by T5 (Tebuconazole@1ml/l) 293.21 and T3 (Carbendazim+Mancozeb @) 2.5g/l) 376.54. Maximum AUDPC was recorded (563.27) under T1 (Untreated/control). Due to the application of Propiconazole, spot blotch disease reduce up to 60.18% and increase chlorophyll contain of the plant, increase different morphological traits of wheat crop as well as also ultimately increase yield up to 35.02%.

Management of spot blotch of wheat using inducer chemicals under field conditions

An experiment was conducted for two consecutive years (2012-13 and 2013-14) to determine the effect of different inducer chemicals on spot blotch disease of wheat and its impact on grain yield. All the inducer chemicals reduced the spot blotch infection significantly at different concentration levels and also increase the yield attributing characters like a number of grains/panicle and 1000 seed weight. The accumulation of phenol increased up to 96 days after sowing (DAS), whereas, peroxidase accumulation increased up to 68 days after sowing in wheat plants in all the treatments. Among the different inducer chemicals, salicylic acid (10-4 M) and CuSO4 (10-4 M and 10-5 M) showed good results even at low concentration levels. Therefore, the inducer chemicals can be used as an alternative method to manage the spot blotch of wheat. DOI.org/10.25174/2249-4065/2019/86740

Genetic Effects of Resistance to Spot Blotch in Selected Wheat Genotypes

Spot blotch disease of wheat (Triticum aestivum L.) caused by Bipolaris sorokiniana (Sacc) Shoemaker causes significant yield and quality losses in warm and humid agro-ecologies of the world. Breeding for resistance is considered to be the most economical and sustainable approach of controlling the disease. The objective of this study was to determine the genetic effect influencing inheritance of resistance to spot blotch in selected wheat genotypes using generation mean analysis to devise a resistance breeding strategy. Populations involving six generations (P1, P2, F1, F2, BCP1 and BCP2) were developed comprising two selected parental lines, i.e., Loerrie II and 19HRWSN6. Test materials were field evaluated for resistance to spot blotch during the 2014/15 cropping season in Zambia. Additive genetic effects were significant and accounted for 94.79% of the total genetic variation for spot blotch resistance in wheat. Dominance and epistatic effects were not detected. The predominance of additive genetic effects suggests that recurrent selection strategy could boost spot blotch resistance in these population to develop pure line wheat cultivars.

Spot blotch disease of wheat: the current status of research on genetics and breeding

The spot blotch disease of wheat is caused by Bipolaris sorokiniana, which is an anamorph (teleomorph Cochliobolus sativus). The disease mainly occurs in warm, humid wheat‐growing regions, and the Eastern Gangetic Plains (EGP) of South Asia is a hotspot. Significant progress has been made in recent years in characterizing the host–pathogen interaction. The study of the pathogen's life cycle and diversity have been an active area of research. A number of resistance sources have also been identified, characterized and used for breeding. Although immunity has not been observed in any genotype, cultivars displaying a relatively high level of resistance have been developed and made available to farmers. Further progress will require regular use of marker‐assisted breeding, genomic selection, gene editing and transgenic interventions. This review summarizes the current state of knowledge about genetic and breeding efforts on the wheat–B. sorokiniana pathosystem and discusses ways in which emerging tools can be used for future research to understand the mechanism involved in infection and for developing cultivars exhibiting a high level of resistance.