Biogenic synthesis, characterization, and evaluation of synthesized nanoparticles against the pathogenic fungus Alternaria solani

In the present study, Trichoderma harzianum culture filtrate (CF) was used as a reducing and capping agent to synthesize silver nanoparticles (Ag NPs) in a quick, simple, cost-effective, and eco-friendly manner. The effects of different ratios (silver nitrate (AgNO3): CF), pH, and incubation time on the synthesis of Ag NPs were also examined. Ultraviolet–visible (UV–Vis) spectra of the synthesized Ag NPs showed a distinct surface plasmon resonance (SPR) peak at 420 nm. Spherical and monodisperse NPs were observed using scanning electron microscopy (SEM). Elemental silver (Ag) was identified in the Ag area peak indicated by energy dispersive x-ray (EDX) spectroscopy. The crystallinity of Ag NPs was confirmed by x-ray diffraction (XRD), and Fourier transform infrared (FTIR) was used to examine the functional groups present in the CF. Dynamic light scattering (DLS) revealed an average size (43.68 nm), which was reported to be stable for 4 months. Atomic force microscopy (AFM) was used to confirm surface morphology. We also investigated the in vitro antifungal efficacy of biosynthesized Ag NPs against Alternaria solani, which demonstrated a significant inhibitory effect on mycelial growth and spore germination. Additionally, microscopic investigation revealed that Ag NP-treated mycelia exhibited defects and collapsed. Apart from this investigation, Ag NPs were also tested in an epiphytic environment against A. solani. Ag NPs were found to be capable of managing early blight disease based on field trial findings. The maximum percentage of early blight disease inhibition by NPs was observed at 40 parts per million (ppm) (60.27%), followed by 20 ppm (58.68%), whereas in the case of the fungicide mancozeb (1,000 ppm), the inhibition was recorded at 61.54%

Advancing crop disease resistance through genome editing: a promising approach for enhancing agricultural production

Modern agriculture has encountered several challenges in achieving constant yield stability especially due to disease outbreaks and lack of long-term disease-resistant crop cultivars. In the past, disease outbreaks in economically important crops had a major impact on food security and the economy. On the other hand climate-driven emergence of new pathovars or changes in their host specificity further poses a serious threat to sustainable agriculture. At present, chemical-based control strategies are frequently used to control microbial pathogens and pests, but they have detrimental impact on the environment and also resulted in the development of resistant phyto-pathogens. As a replacement, cultivating engineered disease-resistant crops can help to minimize the negative impact of regular pesticides on agriculture and the environment. Although traditional breeding and genetic engineering have been instrumental in crop disease improvement but they have certain limitations such as labour intensity, time consumption, and low efficiency. In this regard, genome editing has emerged as one of the potential tools for improving disease resistance in crops by targeting multiple traits with more accuracy and efficiency. For instance, genome editing techniques, such as CRISPR/Cas9, CRISPR/Cas13, base editing, TALENs, ZFNs, and meganucleases, have proved successful in improving disease resistance in crops through targeted mutagenesis, gene knockouts, knockdowns, modifications, and activation of target genes. CRISPR/Cas9 is unique among these techniques because of its remarkable efficacy, low risk of off-target repercussions, and ease of use. Some primary targets for developing CRISPR-mediated disease-resistant crops are host-susceptibility genes (the S gene method), resistance genes (R genes) and pathogen genetic material that prevents their development, broad-spectrum disease resistance. The use of genome editing methods has the potential to notably ameliorate crop disease resistance and transform agricultural practices in the future. This review highlights the impact of phyto-pathogens on agricultural productivity. Next, we discussed the tools for improving disease resistance while focusing on genome editing. We provided an update on the accomplishments of genome editing, and its potential to improve crop disease resistance against bacterial, fungal and viral pathogens in different crop systems. Finally, we highlighted the future challenges of genome editing in different crop systems for enhancing disease resistance

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Not AvailableBipolaris maydis is a phytopathogen of maize that causes maydis leaf blight or Southern corn leaf blight disease. The Biploaris maydis produce extracellular enzymes that degrade cellulose, pectin, amylose and amylopectin of the plant cell wall and helps in invasion and virulence of the phytopathogen in the infected tissue. Variations among the seven isolates of Bipolaris maydis were found for extracellular enzymatic activity in solid medium and the amylase activity showed the highest activity index. E15 isolate of Bipolaris maydis showed the highest amylase, pectinase and esterase activity, whereas, E27 isolate showed highest cellulase activity index as compared to other isolates. The results indicated the possible role of cell wall degrading enzymes in the aggressiveness, virulence and increase the disease incidence of the maydis leaf blight of maizeNot Availabl

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Not AvailableQuality seed is a basic input for crop production in agriculture, and there is always high demand of quality seed in national and international seed trade. The seed health and thereby its quality is affected by various seed-borne pathogens including fungi, bacteria, viruses, nematodes, etc. and also by abiotic factors. The science of seed pathology is an integral part of seed science and technology, which deals with the study of seed-borne diseases, overall seed health status, and management of seed-borne diseases. This science has traveled a long journey of more than a century. Many important institutions have come into existence, and a number of technologies related to seed health testing, detection, and diagnosis of seed-borne microflora and management of the seed-borne pathogens have been developed. To investigate seed health, many tests were standardized by individual researchers and organizations. Paul Neergaard made great contribution in the development of seed pathology, and hence he is considered as the father of seed pathology. Three primary organizations publish standardized seed health testing methods, and these are the International Seed Testing Association (ISTA), the International Seed Health Initiative (ISHI), and the USDA’s National Seed Health System (NSHS). Among them, ISTA is key institution which provides internationally agreed set of rules for seed sampling and testing, gives authority to seed testing laboratories, and provides international seed analysis certificates to facilitate seed trading nationally and internationally. Keeping in the view above facts, the major contributions of different individuals and various organizations are being discussed in this chapter.Not Availabl

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Not AvailableThe plant growth-promoting rhizobacteria (or PGPR) are the beneficial microorganism that colonizes rhizosphere and help in promoting plant growth, protecting from biotic and abiotic stresses, and significantly increasing soil fertility. For the effective ways of developing sustainable agriculture for improving crop productivity with a minimal disturbance to the environment is the exploration of plant growth-promoting rhizobacteria and some other microbe-based symbioses in plants. For increasing crop yields, the use of PGPR has been well proven for its eco-friendly sound by promoting plant growth either direct or indirect mechanism. The mechanisms of plant growth-promoting rhizobacteria include resistance against plant pathogens, solubilizing nutrients for easy uptake, and maintaining the plant growth regulator hormone. This chapter emphasizes an eco-friendly approach to increase crop production and health, the development of sustainable agriculture, the mechanism of PGPR for agricultural sustainability, and the role in different major crop plant varieties along with their mechanism of action.Not Availabl

Development of Diagnostic Markers and Applied for Genetic Diversity Study and Population Structure of Bipolaris sorokiniana Associated with Leaf Blight Complex of Wheat

Bipolaris sorokiniana, a key pathogenic fungus in the wheat leaf blight complex, was the subject of research that resulted in the development of fifty-five polymorphic microsatellite markers. These markers were then used to examine genetic diversity and population structure in Indian geographical regions. The simple sequence repeat (SSR) like trinucleotides, dinucleotides, and tetranucleotides accounted for 43.37% (1256), 23.86% (691), and 16.54% (479) of the 2896 microsatellite repeats, respectively. There were 109 alleles produced by these loci overall, averaging 2.36 alleles per microsatellite marker. The average polymorphism information content value was 0.3451, with values ranging from 0.1319 to 0.5932. The loci’s Shannon diversity varied from 0.2712 to 1.2415. These 36 isolates were divided into two main groups using population structure analysis and unweighted neighbour joining. The groupings were not based on where the isolates came from geographically. Only 7% of the overall variation was found to be between populations, according to an analysis of molecular variance. The high amount of gene flow estimate (NM = 3.261 per generation) among populations demonstrated low genetic differentiation in the entire populations (FST = 0.071). The findings indicate that genetic diversity is often minimal. In order to examine the genetic diversity and population structure of the B. sorokiniana populations, the recently produced microsatellite markers will be helpful. This study’s findings may serve as a foundation for developing improved management plans for the leaf blight complex and spot blotch of wheat diseases in India

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Not AvailableThe plant growth-promoting rhizobacteria (or PGPR) are the beneficial microorganism that colonizes rhizosphere and help in promoting plant growth, protecting from biotic and abiotic stresses, and significantly increasing soil fertility. For the effective ways of developing sustainable agriculture for improving crop productivity with a minimal disturbance to the environment is the exploration of plant growth-promoting rhizobacteria and some other microbe-based symbioses in plants. For increasing crop yields, the use of PGPR has been well proven for its eco-friendly sound by promoting plant growth either direct or indirect mechanism. The mechanisms of plant growth-promoting rhizobacteria include resistance against plant pathogens, solubilizing nutrients for easy uptake, and maintaining the plant growth regulator hormone. This chapter emphasizes an eco-friendly approach to increase crop production and health, the development of sustainable agriculture, the mechanism of PGPR for agricultural sustainability, and the role in different major crop plant varieties along with their mechanism of action.Not Availabl

Preservation of Fungal Culture with Special Reference to Mineral Oil Preservation

Not AvailableIt is very important to preserve fungi so that they can be studied and utilized in future. Fungal resource centres play a key role in conservation of fungi for research pertaining to diversity, taxonomy, epidemiology, biotechnology, biosafety, biosecurity and IPR issues. Preserved cultures of fungal strains are utilized by all stakeholders associated with agriculture, pharmaceutical, brewery and industry for developing new technologies and products for all the sections of the society. Various preservation methods of fungi are given in this chapter with special reference to mineral oil preservation method which is easy, simple and cost-effective as it does not require any sophisticated tool and material. This is the simplest method for preservation of both sporulating-and non-sporulating fungi in any small laboratory and small-scale industry where infrastructure is less.Not Availabl

Trichoderma: Advent of Versatile Biocontrol Agent, Its Secrets and Insights into Mechanism of Biocontrol Potential

Trichoderma is an important biocontrol agent for managing plant diseases. Trichoderma species are members of the fungal genus hyphomycetes, which is widely distributed in soil. It can function as a biocontrol agent as well as a growth promoter. Trichoderma species are now frequently used as biological control agents (BCAs) to combat a wide range of plant diseases. Major plant diseases have been successfully managed due to their application. Trichoderma spp. is being extensively researched in order to enhance its effectiveness as a top biocontrol agent. The activation of numerous regulatory mechanisms is the major factor in Trichoderma ability to manage plant diseases. Trichoderma-based biocontrol methods include nutrient competition, mycoparasitism, the synthesis of antibiotic and hydrolytic enzymes, and induced plant resistance. Trichoderma species may synthesize a variety of secondary metabolites that can successfully inhibit the activity of numerous plant diseases. GPCRs (G protein-coupled receptors) are membrane-bound receptors that sense and transmit environmental inputs that affect fungal secondary metabolism. Related intracellular signalling pathways also play a role in this process. Secondary metabolites produced by Trichoderma can activate disease-fighting mechanisms within plants and protect against pathogens. β- Glucuronidase (GUS), green fluorescent protein (gfp), hygromycin B phosphotransferase (hygB), and producing genes are examples of exogenous markers that could be used to identify and track specific Trichoderma isolates in agro-ecosystems. More than sixty percent of the biofungicides now on the market are derived from Trichoderma species. These fungi protect plants from harmful plant diseases by developing resistance. Additionally, they can solubilize plant nutrients to boost plant growth and bioremediate environmental contaminants through mechanisms, including mycoparasitism and antibiosis. Enzymes produced by the genus Trichoderma are frequently used in industry. This review article intends to provide an overview update (from 1975 to 2022) of the Trichoderma biocontrol fungi, as well as information on key secondary metabolites, genes, and interactions with plant diseases

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Not AvailableAmong the twenty-one bacterial endophytes isolated from Holy basil (Ocimum tenuiflorum), eight were potentially inhibiting the growth of five plant pathogens. Percent suppression of Rhizoctonia solani, Sclerotium rolfsii, Alternaria alternata, Microphomina phaseolina, and Bipolaris sorokiniana radial growth was significantly higher by isolates BTL-4 (70.64%), BTL-1 (80.63%), BTL-1 (57.50%), BTL-5 (81.28%), and GTS-15 (73.81%), respectively. Based on 16S rRNA gene sequencing, these isolates were putatively identified as Bacillus altitudinis (BTL-1 and GTS-16), Bacillus tequilensis (BTL-4), Bacillus safensis (BTL-5), Bacillus haynesii (GTR-8), Bacillus paralicheniformis (GTR-11), Bacillus pacificus (GTR-12), and Bacillus siamensis (GTS-15). Selected endophytes were tested against R. solani in vivo and found to reduce sheath blight disease incidence to a varying extent. Rice plants challenged with R. solani and inoculated with Bacillus altitudinis GTS-16 exhibited the least value of percent infected tillers, recorded maximum induction of defense-related enzymes (phenyl ammonia lyase, peroxidase, and polyphenol oxidase), and enhanced dry matter accumulation. Confocal Scanning Laser Microscope imaging using LIVE/ DEAD™BacLight™ bacterial viability staining has indicated trans-genera colonization of O. tenuiflorum endophytes in rice. Exploring the potential niches like the endosphere could open the vast arena of opportunity for developing newer strains of biocontrol agents.Not Availabl