Control Of Plant Pathogens Research Articles

Food safety and biological control; genomic insights and antimicrobial potential of Bacillus velezensis FB2 against agricultural fungal pathogens.

Development of natural, broad-spectrum, and eco-friendly bio-fungicides is of high interest in the agriculture and food industries. In this context, Bacillus genus has shown great potential for producing a wide range of antimicrobial metabolites against various pathogens. A Bacillus velezensis strain FB2 was isolated from an agricultural field of National Institute for Biotechnology and Genetic Engineering (NIBGE) Faisalabad, Pakistan, exhibiting good antifungal properties. The complete genome of this strain was sequenced, and its antifungal potential was assayed by dual culture method. Moreover, structural characterization of its antifungal metabolites, produced in vitro, were studied. Genome analysis and mining revealed the secondary metabolite gene clusters, encoding non-ribosomal peptides (NRPs) production (e.g., surfactin, iturin and fengycin) and polyketide (PK) synthesis (e.g., difficidin, bacillaene and macrolactin). Furthermore, the Bacillus velezensis FB2 strain was observed to possess in vitro antifungal activity; 41.64, 40.38 and 26% growth inhibition against major fungal pathogens i.e. Alternaria alternata, Fusarium oxysporum and Fusarium solani respectively. Its lipopeptide extract obtained by acid precipitation method was also found effective against the above-mentioned fungal pathogens. The ESI-MS/MS analysis indicated various homologs of surfactin and iturin-A, responsible for their antifungal activities. Overall, this study provides a better understanding of Bacillus velezensis FB2, as a promising candidate for biocontrol purposes, acting in a safe and sustainable way, to control plant pathogens.

GREEN BIOCHEMICAL PROTECTION OF POSTHARVEST TABLE GRAPES AGAINST GRAY MOLD (BOTRYTIS CINEREA) USING 7S PROTEINS

The 7S globulins (seed storage glycoprotein) isolated from soybean and chickpea seeds have the antifungal potential against the pathogenic fungus (Botrytis cinerea) causing gray mold in grapes assessing table grapes in vitro or postharvest by comparing with synthetic fungicide, Switch 62.5 WG. Conventional microbiological procedures estimated the in-vitro antifungal potential of the 7S globulins, such as linear growth curves and scanning electron microscopy (SEM). Soybean-7S significantly inhibited the in-vitro growth of Botrytis cinerea by about 64.44%, 66.64%, and 76.67% when applied at 50, 100, and 200 μg/mL, respectively, followed by chickpea 7S with growth reduction of 52.22%, 54.44%, and 66.67%, respectively. The synthetic fungicide (Switch 62.5 WG) induced higher growth inhibition extents (83.33% and 86.66%) when applied at 50 and 200 μg/mL, respectively. The 7S-exposed B. cinerea displayed swollen hyphae compared with the control under scanning electron microscope examination. The 7S derived from soybean and chickpea inhibited gray mold development in table grapes when applied at 200 and 400 μg/mL for 30 days after infection with B. cinerea. The maintained disease severity was also minimal (40% and 25% for soybean-7S and chickpea-7S, respectively). An increased level of treatment (400 μg/mL) highly reduced the disease severity to only 7.5% after 30 days of storage at cold conditions for both proteins. The 7S globulin from legume seeds can be an alternative to synthetic fungicides for controlling B. cinerea as a postharvest treatment. Developing these legume proteins as natural fungicides could also progress for the safe control of various plant pathogens, causing drastic crop losses.

Application of copper nanoparticles in agricultural biotechnology for plant pathogen control, follicular applications, mutagenesis and elicitation studies

Application of copper nanoparticles in agricultural biotechnology for plant pathogen control, follicular applications, mutagenesis and elicitation studies

Toward sustainable management of ant-hemipteran mutualism in agricultural settings: a comparison of different approaches

Mutualistic associations between ants and honeydew-producing hemipterans have a great ecological and evolutionary significance across terrestrial habitats but can also cause pest outbreaks in agroecosystems. At the same time, ants are often effective predators of several agricultural pests, can improve soil quality, and can control some plant pathogens. Neither ant attendance of hemipteran pests alone, nor a positive correlation between the abundance of ants and hemipterans automatically imply that ants are a worthy target or a key element in hemipteran management strategies. The main tactics in the management of ant-hemipteran associations in agroecosystems include the use of sticky or insecticidal barriers, low-toxicity baits, alternative sugary sources, or ant-adapted biocontrol agents. Barriers can quickly seal ground-nesting ants from the canopy of perennial plants but are unselective towards other arthropods and costly in terms of maintenance. Low-toxicity baits have been particularly tested against invasive and supercolonial ant species and yet are worth considering only when the complete elimination of ant colonies can be desirable. More recently developed and not yet widely available methods based on the provision of alternative sugary sources to manipulate ant behavior can allow to retain or even enhance the contribution of ants to the control of other phytophagous insects or plant pathogens while effective disrupting their mutualism with hemipteran pests. Finally, many parasitoids and predators possess specific adaptations to bypass attending ants, but the existence of species-specific factors complicatesthese networks. Further basic research and longer-term studies are needed to refine and improve the development of sustainable management strategies.

SKRINING DAN UJI DAYA HAMBAT ACTINOMYCETES DARI RIZOSFER TANAMAN KOPI ARABIKA DI KABUPATEN BENER MERIAH TERHADAP Collecotrichum coffeanum

Actinomycetes are microorganisms of a group of gram-positive bacteria that produce uniseluser mycelium. Colonies of Actinomycetes grow slowly, are attached to the substrate and can produce spores. Actinomycetes are known to be able to control plant pathogens. This study aims to screen and study the inhibitory power of Actinomycetes from the rhizosphere of Arabica coffee rhizosphere against Collecotrichum coffeanum. This study found Actinomycetes in the rhizosphere of Arabika coffee plants from Bener Meriah. There were 80 Actinomycetes isolates. Eight of the 21 isolates selected isolate were against Collecotrichum coffeanum with different inhibitory ratios from each isolate. There were 1PRG/RR/10-3/2-1, 2PRG/WP/10-4/1-1-1, 2PRG/AG/10-4/3-1-1, 1M/SR/10-3/2-1, 2M/SR/10-3/2-1, 1M/JAJ/10-3/2-1, 1B//KR/10-3/2, 2B/KR/10-4/1.

Effect of various formulations of Piper aduncum botanical pesticide and concentration levels on fungal pathogen Fusarium oxysporum f.sp. cubense Vegetative Compatibility Group (VCG) 01213/16 Tropical strain 4 and VCG 01218 strain 1

Pathogen of Fusarium oxysporum f.sp. cubence (Foc) Vegetative Compatibility Group (VCG) 01213/16 (Tropical strain/TR4) and VCG 01218 (strain1) are the cause of wilt disease in banana. Plant-based pesticides are an alternative environmentally friendly substance that can control plant pathogens. This study aims to obtain a formulation of Piper aduncum oil with several essential oils to suppress the growth development of two Foc strains that cause wilt disease in banana plants. This study used a complete randomized design in factorial, where the first factor is the type of formulation: F1 = 25% P. aduncum leaf oil, F2 = P. aduncum leaf oil with lemongrass leaf oil (Cymbopogon flexiosus), F3 = P. aduncum oil with citronella leaves (Andropogon nardus), F4 = P. aduncum oil with Ceylon cinnamon leaf oil (Cinnamomum zeylanicum), F5 = P. aduncum oil with Padang cinnamon leaf oil (C. burmanii), F6 = P. aduncum oil with cloves leaf oil (Eugenia aromatica) F7=P. aduncum oil with wild ginger oil (Elettariopsis slahmong). The second factor is the concentration level: 1000, 2000, and 3000 ppm. The results showed that diameter of mycelium between Foc VCG01213/16 and VCG01218 did not differ significantly. However, there were significant differences in the botanical pesticide formulations used. P. aduncum oil formulation mixed with cloves leaf oil and ceylon cinnamon oil at a concentration level of 3000 ppm had better inhibition of colony diameter, namely for Foc VCG01213/16 (90.55% and 88.08%) and on Foc VCG 01218 (90.72% and 89.85%). Likewise, for the inhibition of colony biomass, the best formulation is the P. aduncum oil mixed with cloves leaf oil and with ceylon cinnamon oil, the concentration level at 3000 ppm for Foc VCG 01213/16 were 96.64 and 95.80%, respectively. In contrast, for Foc VCG 01218 were 96.00% for both.

A Review on Soil and Phytomicrobiome for Plant Disease Management

Pests and pathogens significantly reduce crop yields and cost the global economy USD 540 billion annually. The phytomicrobiome is becoming a cornerstone of a comprehensive rethink of agricultural management practices, with microbiome-assisted plant breeding focusing on three principles: minimal soil disturbance, continuous soil cover with crops, cover crops, or a mulch of crop residues, and crop rotation. Plant diseases, phytomicrobiomes, and agricultural practices can all affect plant health. Conservational agricultural practices like minimum tillage and no-tillage have been implemented to reduce anthropogenic activity and preserve microbial diversity. Mulching is a common practice in agriculture to stop moisture loss, maintain soil temperature, control weed growth, and stop soil erosion. Monoculture farming is the practice of cultivating a single crop continuously over several growing seasons on the same field. Intercropping systems encourage the growth of beneficial fungi, such as mycorrhiza, endophytes, saprophytes, decomposers, and bioprotective fungi, and can benefit forest ecosystems by creating disease-suppressive soils. By combining conservation tillage and crop rotation, farmers can reduce disease pressure by disrupting the life cycles of soil-borne pathogens linked to particular crops or genotypes. Composed manure and plant residues can control plant pathogens like Pythium, but the effect is thought to be due to microbial competition or plant host resistance. Green manure can control plant diseases brought on by pathogens in Rhizoctonia, Verticillium, Sclerotinia, Phythophthora, Pythium, Aphanomyces, and Macrophomina, but manure-derived fertilizers may contain antibiotic resistance genes and mobilomes, which could pose risks to both human and animal health. Climate change impacts crop yields by reducing crop physiology and productivity, increasing pathogen diversity, and affecting pathogen genetic traits and speciation. The state of the environment and the availability of suitable hosts significantly impact the ability of these pathogens to survive and spread. However, PGPRs are unpredictable and soil warming can interfere with their effectiveness. Interdisciplinary collaborations between plant biologists, microbiologists, climatologists, and agronomists are required to create effective strategies to reduce the effects of climate change on plant health, crop production, and ecosystem stability.

Algae and cyanobacteria-based biostimulants in controlling plant-parasitic nematodes: a sustainable approach for crop protection

AbstractPlant root pathogens such as bacteria, fungi, nematodes and viruses infect over a thousand plant species worldwide, threatening the livelihood and food security of small-scale farmers and rural communities who rely on the crops. For centuries, soil fumigants have been the standard for disease infestation control; however, due to the hazardous effects of these fumigants and their overall species specificity failure, there has been a paradigm shift away from using chemicals to control plant pathogens in recent decades. The use of algae and cyanobacteria-based biostimulants in combating plant-parasitic nematodes has recently gained the attention of researchers. This review intends to elucidate the state of the art of algae and cyanobacteria-based biostimulants and their bioactive compounds in controlling plant-parasitic nematodes. In addition, given that the mechanisms of action of these biological biostimulants are not fully understood, this review has further elaborated on how these organisms and their bioactive extracts suppress and control plant pest nematodes. Finally, barriers and prospects in commercializing of algae and cyanobacteria-based biostimulants are reviewed.

Multidiscipline, a basic component of innovation in the biological control of plant pathogens

The control of biotic diseases in agriculture — particularly of those caused by fungi and bacteria— has produced an excessive use of chemically-synthesized products (agrochemicals), which, despite their important contribution to the increase of agricultural productivity, have considerable disadvantages, especially regarding the health of the people who apply these products and in environmental terms, since they contaminate soils and groundwater layers. On the other hand, the use of pesticide-free agricultural products has increased in recent years, requiring quality foods, free of toxic components. Alongside this, legislation (especially in developed nations) increasingly limits the use of pesticides on products for human consumption. A more sustainable alternative is the biological control of phytopathogenic fungi and bacteria with the use of their enemies/antagonists, which are considered biological control agents (BCA). In this field, I highlight the recent review by Lahlali et al. (2022) which describes extensively diverse aspects referring to the biological control of phytopathogens, including an analysis of the action mechanisms used by beneficial microorganisms for controlling the phytopathogens and the reduction of the losses caused by them, as well as the potential and limitations of this technology.

Endophytic microorganisms of potato (<i>Solanum tuberosum</i> L.): biodiversity, functions and biotechnological potential

Endophytic communities represent a fascinating inner world of the plants. Endophytes are found in all plant species studied, though the number of microbial cells and their species diversity can differ a lot. The potato (Solanum tuberosum L.) is economically important staple food crop, and the induction of plant resistance to various infections as well as the search for the effective eco-friendly preparations could provide higher potato yields and are very promising for modern agriculture. In this review, we focus on the biodiversity of the potato endophytes and the aspects of their functional importance and possible application in the biological control of plant pathogens. We have systematized literature data regarding the prevention of the harmful effect of pathogenic fungi, bacteria, viruses, and insects resulting from the vital activity of the endophytic microorganisms within the potato plants.

Preliminary assessment of bacterial antibiotic resistance and Candidatus Liberibacter asiaticus titer in three Florida commercial citrus groves

Over the last 16 years, the U.S. citrus industry has been devastated by citrus greening or Huanglongbing (HLB) disease. The causal agent, Candidatus Liberibacter asiaticus (CLas), is an unculturable bacterium transmitted by the invasive Asian citrus psyllid (ACP), Diaphorina citri Kuwayama (Hemiptera: Liviidae), and by grafting. In 2017 and 2019, the Environmental Protection Agency approved foliar applications of the antibiotics streptomycin (STR) and oxytetracycline (OTC) in commercial citrus groves in Florida. This study provides a preliminary assessment of antibiotic spray effects on three commercial citrus groves by quantifying CLas titer from leaves and antibiotic resistant bacterial colony count from leaf, root+rhizosphere, and soil samples. Two groves used antibiotic spray treatment and followed conventional management, one used no antibiotic treatment and was accredited as an organic grove. Samples were plated onto TSA medium containing either STR (100 μg/mL), OTC (15 μg/mL), or no antibiotic (control) then colony-forming units (CFU) per gram of sample were estimated. Among leaf samples, there were no significant differences in CFU or CLas titer based on grove. For soil samples, we found a larger number of resistant CFU in the organic grove. Root+rhizosphere samples from all groves (organic and conventional) showed high prevalence of both STR and OTC-resistant bacteria indicating that plant selective processes during root colonization might favor antibiotic resistant acquisition. The lack of significant difference in CLas titer among the three groves is supported by other studies which suggest that antibiotic spray might not be an effective control for CLas. This research further highlights the need for continued monitoring of antibiotic efficacy to control plant pathogens in commercial settings.

Assessment of Antifungal/Anti-Oomycete Activity of Frass Derived from Black Soldier Fly Larvae to Control Plant Pathogens in Horticulture: Involvement of Bacillus velezensis

Frass, the residual material resulting from the bioconversion of organic matter by black soldier fly larvae (BSFL), has gained attention as a sustainable alternative to conventional fertilizers due to its high nutrient content. Additionally, frass has been found to possess antifungal properties, which can help control plant pathogens affecting horticultural crops. In this study, frass from BSFL reared on the Gainesville diet, a universally employed reference/control diet, was investigated in vitro for its effect on the growth of seven important fungal/oomycete pathogens. Dual culture overlay assays clearly showed that fresh Gainesville diet extract, as well as BSFL frass extract derived from this diet, contained microorganisms producing compound(s) that strongly inhibit(s) the mycelial growth of fungal/oomycete plant pathogens. Fungi and bacteria were then isolated from the fresh Gainesville diet and BSFL frass using the serial dilution technique. Among the different fungi/bacteria isolated, the isolate GV1-11 in Gainesville diet and FGV15-6 in frass demonstrated strong antifungal/anti-oomycete activity. Both isolates were genetically identified by whole-genome sequencing as Bacillus velezensis, a bacterium used as a biocontrol agent, strongly suggesting that B. velezensis, which is present in the Gainesville diet, can survive the process of BSFL rearing and is one of the key factors contributing to the observed antifungal and anti-oomycete activity in the resulting frass. This work underlines the importance of the inherent microbial characteristics of feedstocks on the antifungal/anti-oomycete activity of frass and points out the possibility of exploiting frass to control plant pathogens affecting horticultural crops.

Protective role of plant growth-promoting fungi Aspergillus chevalieri OP593083 and Aspergillus egyptiacus OP593080 as biocontrol approach against Alternaria leaf spot disease of Vicia faba plant

Crop loss brought on by phytopathogens is a significant issue that affects the entire world. Synthetic pesticides have been used for years to prevent economic losses caused by phytopathogens, raising severe worries about the environment and public health. Therefore, today, there is growing interest in using helpful microorganisms to control plant pathogens. In this way, Aspergillus chevalieri AGH-1 OP593083 and Aspergillus egyptiacus AGH-4 OP593080 isolated from wheat rhizosphere have been applied as plant growth-promoting fungi (PGPF) for combating early blight disease caused by Alternaria solani (A. solani) and inducing the defense system and growth promotional strategies in Vicia faba. Two milligrams per milliliter ethyl acetate crude extracts of A. chevalieri and A. egyptiacus demonstrated effective antifungal efficacy against A. solani with an inhibition zone of 18 and 16 mm respectively compared with 20 mm attained by fluconazole as a positive control. Moreover, the minimum inhibitory concentrations (MIC) were (0.25 and 0.5 mg/ml) for A. chevalieri and A. egyptiacus extracts respectively. Data showed that A. chevalieri was the best isolate producing indole acetic acid (IAA) and siderophores (+ + +) followed by A. egyptiacus (+ +). Also, the best isolates capable of phosphate solubilization in the soil was A. egyptiacus (+ + +), followed by A. chevalieri (+ +). It is interesting that the PGPF isolates used, whether single or mixed, showed a significant improvement in all growth and yield as well as photosynthetic pigments in Vicia faba. Moreover, A. chevalieri and A. egyptiacus played an important role in improving plant immunity by increasing phenol, proline, and antioxidant enzymes (POD and PPO) activities, as well as reducing oxidative stress by reducing MDA and H2O2. We can conclude that A. chevalieri and A. egyptiacus are considered eco-friendly safe strong inducers of Vicia faba plant immunity alternatives to chemical pesticides against A. solani early blight to preserve plant, soil, and human health.

Soil core microbiota drive community resistance to mercury stress and maintain functional stability

Soil microbial communities have resistance to environmental stresses and thus can maintain ecosystem functions such as decomposition, nutrient provisioning, and plant pathogen control. However, predominant factors driving community resistance of soil microbiome to heavy metal pollution stresses and ecosystem functional stability are still unclear, limiting our ability to forecast how soil pollution might affect ecosystem sustainability. Here, we conducted microcosm experiments to estimate the importance of soil microbiome in predicting community resistance to heavy metal mercury (Hg) stress in paired paddy and upland fields. We found that community resistance of soil microbiome was strongly correlated with ecosystem functional stability, so were the individual groups of organisms such as bacteria, saprotrophic fungi, and phototrophic protists. The core phylotypes within soil microbiome had a major contribution to community resistance, which was essential for the maintenance of functional stability. Co-occurrence network further confirmed that community resistances of main ecological clusters were positively correlated with ecosystem functional stability. Together, our results provide new insights into the link between community resistance and functional stability, and highlight the importance of core microbiota in driving community resistance to environmental stresses and maintain functional stability.

Multifaceted Impacts of Plant-Beneficial Pseudomonas spp. in Managing Various Plant Diseases and Crop Yield Improvement.

The modern agricultural system has issues with the reduction of agricultural productivity due to a wide range of abiotic and biotic stresses. It is also expected that in the future the entire world population may rapidly increase and will surely demand more food. Farmers now utilize a massive quantity of synthetic fertilizers and pesticides for disease management and to increase food production. These synthetic fertilizers badly affect the environment, the texture of the soil, plant productivity, and human health. However, agricultural safety and sustainability depend on an ecofriendly and inexpensive biological application. In contrast to synthetic fertilizers, soil inoculation with plant-growth-promoting rhizobacteria (PGPR) is one of the excellent alternative options. In this regard, we focused on the best PGPR genera, Pseudomonas, which exists in the rhizosphere as well as inside the plant's body and plays a role in sustainable agriculture. Many Pseudomonas spp. control plant pathogens and play an effective role in disease management through direct and indirect mechanisms. Pseudomonas spp. fix the amount of atmospheric nitrogen, solubilize phosphorus and potassium, and also produce phytohormones, lytic enzymes, volatile organic compounds, antibiotics, and secondary metabolites during stress conditions. These compounds stimulate plant growth by inducing systemic resistance and by inhibiting the growth of pathogens. Furthermore, pseudomonads also protect plants during different stress conditions like heavy metal pollution, osmosis, temperature, oxidative stress, etc. Now, several Pseudomonas-based commercial biological control products have been promoted and marketed, but there are a few limitations that hinder the development of this technology for extensive usage in agricultural systems. The variability among the members of Pseudomonas spp. draws attention to the huge research interest in this genus. There is a need to explore the potential of native Pseudomonas spp. as biocontrol agents and to use them in biopesticide development to support sustainable agriculture.

Why Are There No Widely Successful Microbial Bioherbicides for Weed Management in Crops?

Microbial biopesticides to control plant pathogens and insects in crops have had significant success. However, there have been relatively few successes for microbiol bioherbicides in crops, despite considerable publication and commercial product introductions in this area. Marketed microbial bioherbicide products for use in agriculture have been largely unsuccessful. This paper covers the potential advantages of successful microbial bioherbicides, as well as the biological and technical issues that have limited the success of such products. Technologies to overcome the problems that have limited the success of these products are discussed. The many advantages of using killed microbial products (e.g., cell-free filtrates) over living microbial products as bioherbicides are detailed. A commercialized mycoherbicide that has been selected for in the lab for control of the parasitic weed Striga hermonthica is being used with some success in Africa, indicating that non-transgenic modification of the genetics of bioherbicide microbes for improved efficacy is acceptable to some regulatory authorities. Genetic modifications to improve efficacy and host range, as well as improved application technology to greatly reduce the amount of product needed are the two technologies that are likely to expand the use of microbial bioherbicides in the future. This article is protected by copyright. All rights reserved.

Plant virus resistance biotechnological approaches: From genes to the CRISPR/Cas gene editing system

Plant viruses cause crop losses in agronomically and economically important crops, making global food security a challenge. Although traditional plant breeding has been effective in controlling plant viral diseases, it is unlikely to solve the problems associated with the frequent emergence of new and more virulent virus species or strains. As a result, there is an urgent need to develop alternative virus control strategies that can be used to more easily contain viral diseases. A better understanding of plant defence mechanisms will open up new avenues for research into plant- pathogen interactions and the development of broad-spectrum virus resistance. The scientific literature was evaluated and structured in this review, and the results of the reliability of the methods of analysis used were filtered. As a result, we described the molecular mechanisms by which viruses interact with host plant cells. To develop an effective strategy for the control of plant pathogens with a significant intensity on the agricultural market, clear and standardised recommendations are required. The current review will provide key insights into the molecular underpinnings underlying the coordination of plant disease resistance, such as main classes of resistance genes, RNA interference, and the RNA-mediated adaptive immune system of bacteria and archaea – clustered regularly interspaced short palindromic repeats (CRISPR) and CRISPR-associated Cas proteins – CRISPR/Cas. Future issues related to resistance to plant viral diseases will largely depend on integrated research to transfer fundamental knowledge to applied problems, bridging the gap between laboratory and field work.

Phyllosphere symbiont promotes plant growth through ACC deaminase production

Plant growth promoting bacteria can confer resistance to various types of stress and increase agricultural yields. The mechanisms they employ are diverse. One of the most important genes associated with the increase in plant biomass and stress resistance is acdS, which encodes a 1-aminocyclopropane-1-carboxylate- or ACC-deaminase. The non-proteinogenic amino acid ACC is the precursor and means of long-distance transport of ethylene, a plant hormone associated with growth arrest. Expression of acdS reduces stress induced ethylene levels and the enzyme is abundant in rhizosphere colonizers. Whether ACC hydrolysis plays a role in the phyllosphere, both as assembly cue and in growth promotion, remains unclear. Here we show that Paraburkholderia dioscoreae Msb3, a yam phyllosphere symbiont, colonizes the tomato phyllosphere and promotes plant growth by action of its ACC deaminase. We found that acdS is required for improved plant growth but not for efficient leaf colonization. Strain Msb3 readily proliferates on the leaf surface of tomato, only occasionally spreading to the leaf endosphere through stomata. The strain can also colonize the soil or medium around the roots but only spreads into the root if the plant is wounded. Our results indicate that the degradation of ACC is not just an important trait of plant growth promoting rhizobacteria but also one of leaf dwelling phyllosphere bacteria. Manipulation of the leaf microbiota by means of spray inoculation may be more easily achieved than that of the soil. Therefore, the application of ACC deaminase containing bacteria to the phyllosphere may be a promising strategy to increasing plant stress resistance, pathogen control, and harvest yields.

Bacterial Bioprotectants: Biocontrol Traits and Induced Resistance to Phytopathogens

Plant growth and nutrition are adversely affected by various factors such as water stress, high temperature, and plant pathogens. Plant-associated microbes play a vital role in the growth and development of their hosts under biotic and abiotic stresses. The use of a rhizosphere microbiome for plant growth stimulation and the biological control of fungal disease can lead to improved crop productivity. Mechanisms used by plant-growth-promoting rhizobacteria (PGPR) to protect plants from soilborne pathogens include antibiosis, the production of lytic enzymes, indole-3 acetic acid production, decreasing ethylene levels by secreting 1-aminocyclopropane-1-carboxylate deaminase, competition for nutrients and niches, parasitism and induced systemic resistance. In this review, we emphasize the biological control of plant pathogens by root-associated microbes and discuss traits involved in pathogen reduction. Future research should focus on the effect of root exudation on plant–pathogen interactions under various abiotic factors. Moreover, the development of microbial fungicides with longer shelf lives will help farmers to opt for organic agriculture, reducing the use of chemical fertilizers. This trend is expected to drive the adoption of biological control methods in agriculture. The future prospects for the biological control of plant diseases are bright and are expected to play an increasingly important role in sustainable agriculture.

Biological Agent Trichoderma asperellum and Its in Vitro Inhibitory Activity Against Mango Fruit Rot Pathogens

Diseases are one of the major challenges in crop production which can lead to significant economic losses. Ironically, while having multiple negative impacts, synthetic chemical pesticides are considered the main strategy in tackling plant diseases. Trichoderma asperellum is one of the potential fungal species that can inhibit numerous plant diseases. This study reconfirmed the morphological characteristics of Trichoderma isolates obtained and identified it by molecular techniques. In addition, the inhibitory activity of the isolates was tested in vitro against the mango pathogens Colletotrichum asianum and Diaporthe pseudophoenicicola. The results showed that isolate T4 was identified as Trichoderma asperellum. Isolate T4 was able to inhibit C. asianum and D. pseudophoenicicola by 28.19% and 15.64%, respectively. Therefore, this isolate can be used as a biological agent to control plant pathogens in an environmentally friendly, sustainable manner, and as an alternative to synthetic chemical pesticides.