Biocontrol Of Plant Pathogens Research Articles

Biocontrol of plant pathogens by Lysobacter enzymogenes isolate LEC: efficacy of shake flask broth, fermentation broth and dried preparations

ABSTRACT The aim of our study was to upscale the production of Lysobacter enzymogenes strain LEC from shake flasks to a laboratory bioreactor. The obtained fermentation broth was to be downstream-processed by lyophilisation and fluidised bed-drying, followed by testing of the dried preparations against plant pathogens. Different batches of broth from shake flasks and from individual fermenter runs were characterised and compared. Number of viable cells, in vitro efficacy (ED90 value) against the apple scab pathogen Ventura inaequalis, as well as efficacy against Phytophthora infestans on potato plants were all reproducible and not impaired by upscaling the production volume from shake flask to the bioreactor. Fermentation broth was processed by lyophilisation and fluidised bed-drying. In bioassays, the activity against downy mildew (Pseudoperonospora cubensis) on cucumber were comparable for the unformulated fermentation broth and the fluidised bed-dried product, while the lyophilised product was significantly more effective. Strain LEC showed reproducible pathogen suppressive activity, independent from production scale and batch. Production upscaling and formulation by drying are possible without loss of efficacy.

Unravelling the secrets of soil microbiome and climate change for sustainable agroecosystems.

The soil microbiota exhibits an important function in the ecosystem, and its response to climate change is of paramount importance for sustainable agroecosystems. The macronutrients, micronutrients, and additional constituents vital for the growth of plants are cycled biogeochemically under the regulation of the soil microbiome. Identifying and forecasting the effect of climate change on soil microbiomes and ecosystem services is the need of the hour to address one of the biggest global challenges of the present time. The impact of climate change on the structure and function of the soil microbiota is a major concern, explained by one or more sustainability factors around resilience, reluctance, and rework. However, the past research has revealed that microbial interventions have the potential to regenerate soils and improve crop resilience to climate change factors. The methods used therein include using soil microbes' innate capacity for carbon sequestration, rhizomediation, bio-fertilization, enzyme-mediated breakdown, phyto-stimulation, biocontrol of plant pathogens, antibiosis, inducing the antioxidative defense pathways, induced systemic resistance response (ISR), and releasing volatile organic compounds (VOCs) in the host plant. Microbial phytohormones have a major role in altering root shape in response to exposure to drought, salt, severe temperatures, and heavy metal toxicity and also have an impact on the metabolism of endogenous growth regulators in plant tissue. However, shelf life due to the short lifespan and storage time of microbial formulations is still a major challenge, and efforts should be made to evaluate their effectiveness in crop growth based on climate change. This review focuses on the influence of climate change on soil physico-chemical status, climate change adaptation by the soil microbiome, and its future implications.

Application of Plant Growth Promoting Rhizobacteria on Vegetative Growth in Chili Plants (Capsicum frutescens L.)

Cayenne pepper is a significant plant in tropical regions, utilized not only as a culinary spice but also in the pharmaceutical industry. An effective strategy for enhancing the physical, chemical, and biological quality of soil is the employment of plant growth-promoting rhizobacteria (PGPR). PGPR, a soil microorganism that colonizes plant roots, can accelerate growth and protect against certain pathogens. The use of PGPR, particularly in biocontrol of plant pathogens and biofertilization, is prevalent across various global regions. This study evaluates the effectiveness of PGPR in boosting the growth of cayenne pepper and was conducted in Peresak Village, Narmada District, West Lombok Regency, NTB Province. The methodology implemented was a Completely Randomized Design (CRD) experiment with five treatments and five replications, totaling 25 plant units. The treatments included a control (P0 ml/L) and four PGPR concentrations: P1 (10 ml/L), P2 (20 ml/L), P3 (30 ml/L), and P4 (40 ml/L). Each PGPR dose was dissolved in 1 liter of water and administered at 200 ml per polybag. The findings indicated that PGPR application significantly impacted the growth of cayenne pepper plants, notably increasing plant height, leaf count, branch count, and flower count. The 30 ml/L PGPR concentration (P3) proved most effective in enhancing these growth parameters. The results underscore the substantial benefits of incorporating PGPR as a biofertilizer agent in agricultural practices to optimize crop yields.

THE OCCURRENCE OF PESTICIDES IN ENVIRONMENT AND CURRENT TECHNOLOGIES FOR THEIR REMEDIATION AND MANAGEMENT

Agriculture is facing major challenges affected by erosion, salinity and soil degradation. Chemical pesticides and fungicides are more used the agricultural lands. Chemical pesticides and fungicides are more used environment and human diseases causes. The better approaches in agriculture, biocontrol microorganisms, and Plant Growth Promoting (PGP) have emerged as safe for the environment, and also safe alternatives to chemical pesticides. Plant associated microorganisms have helped in soil nutrients enhancement, nitrogen fixation, phosphate solubilization, siderophore production, β-1,3glucanase, cellulase, protease, and lipases. These microbes have tolerances to the biotic and abiotic stress, pH, salinity drought, extremes temperature, heavy metals, and pesticide pollution. This summarized and discussed in this review evaluated actinomycetes related research and its benefits. These bacteria are biocontrol of plant pathogens and enhance the plant growth in agriculture.

The Effect of Conventional and Conservative Tillage Systems on Microbial Community Composition and Physiological Activity in Soils from Bărăgan Plain

The paper aimed to present the results of research carried out on size, taxonomic composition and physiological activity of soil microbiota for assessing the effect of classic (conventional) and conservative (minimum tillage) agriculture systems applied in a zone affected by aridification from Bărăgan Plain. Significant differences concerning the quantitative parameters characterizing the bacterial and fungal communities from the two soil systems of tillage have been evidenced. Total counts of bacteria doubled and total counts of fungi was with one order of magnitude higher in soil minimum-tilled than in soil under conventional tillage system. Soil respiration values registered for both conservative and conventional systems are considered to characterize high levels of microbial physiological activities, with slightly higher values for minimum tillage system application than for conventional system. The beneficial effect of conservative system was evidenced by higher values of diversity indices registered for both bacterial and, especially fungal communities, as compared with those characterizing the communities from soil under conventional tillage system. The minimum tillage system favoured the increasing of abundance and diversity of actinomycetes, the dominance of Pseudomonas and Bacillus bacterial species and fungal species belonging to genera Aspergillus, Trichoderma, Mortierella and Paecilomyces in composition of soil microbiota, with multiple roles in main soil processes: decomposition of vegetal residues, synthesis of humus precursors, carbon sequestration, alleviation of various abiotic stress (drought, salinity), increasing accessibility of nutrients for plants, yields, biocontrol of plant pathogens.

Evaluating the potential of Bacillus licheniformis YZCUO202005 isolated from lichens in maize growth promotion and biocontrol

Lichens exist in an organismal organization of mycobiont, photobiont, and non-photoautotrophic bacteria. These organisms contribute to the growth of lichens even in poor nutrition substrates. However, studies on the isolation and application of non-photoautotrophic bacteria in plant growth and biocontrol are scanty. Therefore, a study was conducted to isolate and evaluate the potential of non-photoautotrophic bacteria from lichen tissues in maize plant growth promotion and biocontrol of plant pathogens (fungi and bacteria). Five bacterial strains were isolated and tested for their ability to produce indole-3-Acetic Acid (IAA). One bacterium named YZCUO202005 produced IAA, siderophores and biofilms, solubilized phosphate and potassium and exhibited extracellular enzymes (cellulases, proteases, amylase, and β −1,3-Glucanase). Based on the 16S rRNA sequence analysis results, YZCUO202005 was identified as Bacillus licheniformis. The strain inhibited the growth of five pathogenic fungi with an inhibition percent of between 58.7% and 71.7% and two pathogenic bacteria. Under greenhouse conditions, YZCUO202005 was tested for its abilities to enhance maize seed germination, and vegetative growth. Compared with the control treatment, the strain significantly enhanced the growth of stem length (i.e. 18 ± 0.64 cm, 78 ± 0.92 cm), leaf length (i.e. 10 ± 0.36 cm, 57 ± 1.42 cm), leaf chlorophyll levels (i.e., 13 ± 0.40, 40 ± 0.43 SPAD), and root length (i.e, 9.8 ± 2.25 cm, 22.5 ± 6.59 cm). Our results demonstrated that B. licheniformis YZCUO202005 from lichens has the potential to promote plant growth and reduce fungal and bacterial pathogens’ growth. Furthermore, the results suggest that lichens are naturally rich sources of plant growth promotion and biocontrol agents that would be used in agriculture.

Bacterial Endophytes, a resilient way toward sustainable agriculture: provide plant growth promotion and biocontrol of plant pathogens

Plant pathogens are considered a major constraint in decreasing the quality and quantity of plants and plant products by attacking the seed from its germination to the harvesting stage. To date, various multifunctional chemical pesticides have been applied to control these infectious entities, but these chemical pesticides are not as effective in controlling them. That is why "bacterial endophytes," an alternative to these chemical pesticides, have been determined in the history of mankind through multidisciplinary ways. At the same time, these endophytes work to save the living environment, improve plant growth, and control infectious plant pathogens. The current study summarizes and analyzes the pioneering and recent works on plant bacterial endophytes and their mechanisms as biocontrol agents/plant growth promotion, interaction with the host plant, root colonization, systemic colonization of aerial plant tissues, phytohormone production and modulation, host specificity, genes expressed in the endosphere, multi-omics approaches to improve endophyte use, and biopesticide formulation by these bacterial endophytes. The manuscript highlights the most necessary information about bacterial endophytes, and the study will play a vital role in the further use and handling of these bacterial endophytes for sustainable agricultural production.

Nature’s Antimicrobial Arsenal: Non-Ribosomal Peptides from PGPB for Plant Pathogen Biocontrol

Non-ribosomal peptides (NRPs) are a diverse group of bioactive compounds synthesized by microorganisms, and their antimicrobial properties make them ideal candidates for use as biocontrol agents against pathogens. Non-ribosomal peptides produced by Plant-Growth-Promoting Bacteria (PGPB) have gained interest for the biocontrol of plants’ bacterial and fungal pathogens. In this review, the structure and mode of action of NRPs, including their characterization and the characterization of NRP-producing microorganisms, are discussed. The use of NRPs in soilless agriculture and their potential as part of a sustainable plant disease control strategy are also highlighted. In addition, the review debates the commercial aspects of PGPB’s formulations and their potential as a biocontrol agent. Overall, this review emphasizes the importance of NRPs derived from PGPB in the biocontrol of plant pathogens and their potential to be used as an environmentally friendly and sustainable plant disease control strategy.

Understanding the sugar beet holobiont for sustainable agriculture.

The importance of crop-associated microbiomes for the health and field performance of plants has been demonstrated in the last decades. Sugar beet is the most important source of sucrose in temperate climates, and-as a root crop-yield heavily depends on genetics as well as on the soil and rhizosphere microbiomes. Bacteria, fungi, and archaea are found in all organs and life stages of the plant, and research on sugar beet microbiomes contributed to our understanding of the plant microbiome in general, especially of microbiome-based control strategies against phytopathogens. Attempts to make sugar beet cultivation more sustainable are increasing, raising the interest in biocontrol of plant pathogens and pests, biofertilization and -stimulation as well as microbiome-assisted breeding. This review first summarizes already achieved results on sugar beet-associated microbiomes and their unique traits, correlating to their physical, chemical, and biological peculiarities. Temporal and spatial microbiome dynamics during sugar beet ontogenesis are discussed, emphasizing the rhizosphere formation and highlighting knowledge gaps. Secondly, potential or already tested biocontrol agents and application strategies are discussed, providing an overview of how microbiome-based sugar beet farming could be performed in the future. Thus, this review is intended as a reference and baseline for further sugar beet-microbiome research, aiming to promote investigations in rhizosphere modulation-based biocontrol options.

Soil Microbiome: A Treasure Trove for Soil Health Sustainability under Changing Climate

Climate change imprints on soil are projected primarily through the changes in soil moisture and surge in soil temperature and CO2 levels in response to climate change and is anticipated to have varying impacts on soil characteristics and processes that are instrumental in the restoration of soil fertility as well as productivity. Climate change encompasses a major concern of sharing its impact on the stability and functionality of soil microbiome and is characterized by one or more chief stability metrics encircling resistance, resilience, and functional redundancy. Nevertheless, the explorations over the past years have unveiled the potential of microbial interventions in the regeneration of soils or assurance of perked-up resilience to crops. The strategies involved therein encompass harnessing the native capability of soil microbes for carbon sequestration, phyto-stimulation, bio fertilization, rhizo-mediation, biocontrol of plant pathogens, enzyme-mediated breakdown, antibiosis, prompting of anti-oxidative defense mechanism, exudation of volatile organic compounds (VOCs) and induced systemic resistance (ISR) response in the host plant. However, the short storage and shelf-life of microbe-based formulations stay a significant constraint and rigorous efforts are necessary to appraise their additive impact on crop growth under changing climate scenarios.

Volatile Organic Compound (VOC) Profiles of Different Trichoderma Species and Their Potential Application.

Fungi emit a broad spectrum of volatile organic compounds (VOCs), sometimes producing species-specific volatile profiles. Volatilomes have received over the last decade increasing attention in ecological, environmental and agricultural studies due to their potential to be used in the biocontrol of plant pathogens and pests and as plant growth-promoting factors. In the present study, we characterised and compared the volatilomes from four different Trichoderma species: T. asperellum B6; T. atroviride P1; T. afroharzianum T22; and T. longibrachiatum MK1. VOCs were collected from each strain grown both on PDA and in soil and analysed using proton transfer reaction quadrupole interface time-of-flight mass spectrometry (PTR-Qi-TOF-MS). Analysis of the detected volatiles highlighted a clear separation of the volatilomes of all the four species grown on PDA whereas the volatilomes of the soil-grown fungi could be only partially separated. Moreover, a limited number of species-specific peaks were found and putatively identified. In particular, each of the four Trichoderma species over-emitted somevolatiles involved in resistance induction, promotion of plant seed germination and seedling development and antimicrobial activity, as 2-pentyl-furan, 6PP, acetophenone and p-cymene by T. asperellum B6, T. atroviride P1, T. afroharzianum T22 and T. longibrachiatum MK1, respectively. Their potential role in interspecific interactions from the perspective of biological control is briefly discussed.

NMR Metabolomics and Chemometrics of Lettuce, Lactuca sativa L., under Different Foliar Organic Fertilization Treatments.

Lettuce plants were grown in a greenhouse affected by the fungal pathogen Fusarium oxysporum to test the effects on plant metabolomics by different organic treatments. Three foliar application treatments were applied: a commercial compost tea made of aerobically fermented plant organic matter, a pure lyophilized microalga Artrospira platensis, commonly named spirulina, and the same microalga previously exposed during its culture to a natural uptake from medium enriched with F. oxysporum fragmented DNA (NAT). The experiment is the first attempt to observe in field conditions, the use and effects of a natural microbial library as a carrier of pathogenic fungal DNA for disease control. Untargeted NMR metabolomics and chemometrics showed that foliar organic application significantly reduced fumaric and formic acids, aromatic amino acids, and nucleosides, while increasing ethanolamine. A strong decrease in phenolic acids and an increase in citric acid and glutamine were specifically observed in the NAT treatment. It is noteworthy that the exposure of a known biostimulant microalga to fungal DNA in its culture medium was sufficient to induce detectable changes in the metabolomic profiles of the fertilized plants. These findings deserve further investigation to assess the potential relevance of the presented approach in the field of crop biostimulation and biocontrol of plant pathogens.

Characterisation of Trichoderma spp. and Assessment as Biocontrol Using Dual Culture Assay Against Fungi Associated with Black Pepper (Piper nigrum L.) Diseases in Sarawak

Black pepper (Piper nigrum L.) is one of the most widely used spices in food, beverage, cosmetics, and medicine. Black pepper production has suffered from various fungal diseases. Microbial biological control is an essential part of integrated disease management to reduce the heavy reliance on chemical fungicides. Trichoderma fungi comprise a large group of rhizocompetent filamentous fungi widely used in the biocontrol of plant pathogens. Three field surveys conducted on five black pepper farms in Belaga, Sarawak, identified three fungal diseases: yellowing, black berry, and foot rot. Based on the morphological and molecular characterisation, the identified fungal causal agents were Fusarium solani (yellowing disease), Colletotrichum gloeosporioides (black berry disease), and Phytophthora palmivora (foot rot disease). Twenty isolates of Trichoderma spp. were isolated from secondary forest and Biopark in Bintulu, Sarawak. Trichoderma isolates were characterised based on the morphological characteristics and molecular phylogenetic analysis using the rDNA internal transcribed spacer (ITS) region. Trichoderma isolates were separated into five distinct species, namely T. harzianum, T. virens, T. brevicompactum, T. tawa, and telomorphic Hypocrea lixii. Among the Trichoderma fungi, T. harzianum was the most frequently (65%) isolated species. Trichoderma harzianum (Isolates of TJ9, 10, and 16) showed antagonistic and inhibitory effects by 61 to 70% on in vitro mycelial growth against three common fungal pathogens of black pepper, P. palmivora, C. gloeosporioides, and F. solani. This study highlights the potential of using native Trichoderma fungi as biocontrol agents in the black pepper integrated disease management program.

Current Status and Future Perspective on Enzyme Involving in Biocontrol of Plant Pathogen

Plant diseases must be controlled to maintain the quality and quantity of food produced by farmers worldwide. Various strategies exist to prevent, reduce, or manage plant diseases. Agronomic and horticultural methods depend on chemical fertilisers and insecticides. These agricultural inputs have contributed significantly to recent gains in crop output and quality. Microbial enzymes help bacteria multiply in a specific habitat by acting as biocatalysts for biochemical processes. It has long been recognised that rhizosphere microorganisms may boost plant development and suppress phytopathogens. Rhizosphere microorganisms may help plants fight phytopathogens in numerous ways. Excreting lytic enzymes is one of the acknowledged biocontrol methods for preventing phytopathogens from surviving in the rhizosphere. To combat phytopathogens, rhizosphere microbes create chitinases, cellulases, proteases, and glucanases. Biological management may soon replace fungicides, say UBC researchers. New molecular approaches are now available to study antagonist-pathogen interactions, rhizosphere antagonist ecology, and biocontrol agent efficacy. Because agro-ecosystems are dynamic structures with numerous factors affecting disease and crop productivity, alternative IPM strategies to manage crop diseases are useful in various environments. Diverse crop systems need IPM management options other than biological control to successfully prevent disease development and yield loss.

Use of beneficial bacterial endophytes: A practical strategy to achieve sustainable agriculture.

Beneficial endophytic bacteria influence their host plant to grow and resist pathogens. Despite the advantages of endophytic bacteria to their host, their application in agriculture has been low. Furthermore, many plant growers improperly use synthetic chemicals due to having no or little knowledge of the role of endophytic bacteria in plant growth, the prevention and control of pathogens and poor access to endobacterial bioproducts. These synthetic chemicals have caused soil infertility, environmental contamination, disruption to ecological cycles and the emergence of resistant pests and pathogens. There is more that needs to be done to explore alternative ways of achieving sustainable plant production while maintaining environmental health. In recent years, the use of beneficial endophytic bacteria has been noted to be a promising tool in promoting plant growth and the biocontrol of pathogens. Therefore, this review discusses the roles of endophytic bacteria in plant growth and the biocontrol of plant pathogens. Several mechanisms that endophytic bacteria use to alleviate plant biotic and abiotic stresses by helping their host plants acquire nutrients, enhance plant growth and development and suppress pathogens are explained. The review also indicates that there is a gap between research and general field applications of endophytic bacteria and suggests a need for collaborative efforts between growers at all levels. Furthermore, the presence of scientific and regulatory frameworks that promote advanced biotechnological tools and bioinoculants represents major opportunities in the applications of endophytic bacteria. The review provides a basis for future research in areas related to understanding the interactions between plants and beneficial endophytic microorganisms, especially bacteria.

Biosynthesis Pathways, Transport Mechanisms and Biotechnological Applications of Fungal Siderophores.

Iron (Fe) is the fourth most abundant element on earth and represents an essential nutrient for life. As a fundamental mineral element for cell growth and development, iron is available for uptake as ferric ions, which are usually oxidized into complex oxyhydroxide polymers, insoluble under aerobic conditions. In these conditions, the bioavailability of iron is dramatically reduced. As a result, microorganisms face problems of iron acquisition, especially under low concentrations of this element. However, some microbes have evolved mechanisms for obtaining ferric irons from the extracellular medium or environment by forming small molecules often regarded as siderophores. Siderophores are high affinity iron-binding molecules produced by a repertoire of proteins found in the cytoplasm of cyanobacteria, bacteria, fungi, and plants. Common groups of siderophores include hydroxamates, catecholates, carboxylates, and hydroximates. The hydroxamate siderophores are commonly synthesized by fungi. L-ornithine is a biosynthetic precursor of siderophores, which is synthesized from multimodular large enzyme complexes through non-ribosomal peptide synthetases (NRPSs), while siderophore-Fe chelators cell wall mannoproteins (FIT1, FIT2, and FIT3) help the retention of siderophores. S. cerevisiae, for example, can express these proteins in two genetically separate systems (reductive and nonreductive) in the plasma membrane. These proteins can convert Fe (III) into Fe (II) by a ferrous-specific metalloreductase enzyme complex and flavin reductases (FREs). However, regulation of the siderophore through Fur Box protein on the DNA promoter region and its activation or repression depend primarily on the Fe availability in the external medium. Siderophores are essential due to their wide range of applications in biotechnology, medicine, bioremediation of heavy metal polluted environments, biocontrol of plant pathogens, and plant growth enhancement.

Antimicrobial Compounds Biosynthesis and Biocontrol Mechanisms of Lysobacter enzymogenes

Biocontrol of plant pathogens is considered an environmentally friendly strategy and it is preferred over the use of chemicals which cause environmental pollution. Lysobacter enzymogenes is a bacterium that has been identified as an agriculturally important biocontrol agent. L. enzymogenes possess antagonistic activity against numerous phytopathogens such as fungi, oomycetes, bacteria and nematodes. Its antagonistic activity is conferred by its ability to produce bioactive secondary metabolites such as the Heat-Stable Anti-Fungal Factor (HSAF), Heat-Stable Degrading Metabolite (HSDM) and WAP-8294A2. It can also produce abundant lytic enzymes such as; chitinases, proteases, glucanases and cellulases that can degrade fungal cell walls and therefore inhibit their growth. To design effective biocontrol strategies employing L. enzymogenes, it is important to understand its antagonistic mechanisms. This review crystalizes information on the biosynthesis mechanisms and biocontrol mechanisms of various antimicrobial compounds produced by L. enzymogenes, this information is essential in designing biocontrol strategies against phytopathogens. Further, this review highlights the uncharacterized HSDM and proposes the need for its future characterization, determination of its biosynthetic gene cluster and characterization of its antagonistic mechanisms against various phytopathogens. Also, the mechanism of clp regulation of lytic enzymes biosynthesis needs to be further studied.

Selection of bacteria and fungi for control of soilborne seedling diseases of maize

Plant-based screening experiments were conducted with the aim of identifying biocontrol bacteria and fungi for seed treatment of maize. Candidate microorganisms were evaluated for their protective effects against soilborne infections by species of Fusarium, Globisporangium (syn. Pythium) and Rhizoctonia. The microorganisms tested were bacteria and fungi from maize roots or other sources, including some active microbial components of commercial biocontrol products. Due to the method of isolation chosen, the majority of bacteria from maize roots were spore formers, most of them species of the genera Bacillus,Brevibacillus and Paenibacillus. In pot tests with the potting substrate inoculated with F. culmorum, the level of control provided by seed treatment with the most efficacious bacterial and fungal isolates was comparable or close to the chemical reference seed treatment thiram. The most effective bacteria were species of Pseudomonas, Burkholderia and Streptomyces. Among a subset of approx. 100 bacteria studied, the in vivo and in vitro activities against F.culmorum were only weakly correlated, although some strains deviated from this pattern. The most effective fungi were two strains of Clonostachys rosea and isolates of Trichoderma. The latter and a strain of Gliocladium virens provided also protection against R.solani. Activity against Globisporangium ultimum was recorded for one isolate of Trichoderma and the two strains of C. rosea. A reduction in the impact of seedborne F. culmorum was also observed after seed treatment with two strains of F. oxysporum f. sp. strigae. The results are discussed in relation to previous reports on rhizosphere bacteria of maize and their use in biocontrol of plant pathogens or for plant growth promotion.

Current Status and Future Perspective on Enzyme Involving in Biocontrol of Plant Pathogen

To sustain the quality and abundance of fruit, feed and fiber provided by farmers all over the world, plant diseases must be regulated. Plant diseases may be prevented, mitigated, or regulated using a variety of methods. Growers also rely on chemical fertilizers and pesticides for good agronomic and horticultural practices. Such agricultural inputs have taken a vital part in spectacular increases in crop yield and quality over the last 100 years. Microbial enzymes function as biocatalysts for key biochemical reactions and also assist microbes reproduce in a particular niche. The ability of rhizosphere microorganism to increase the growth of plant and control phytopathogens has long been known. Rhizosphere microbes may aid plants in several ways in their fight against phytopathogens. Of all recognized biocontrol pathways, the excretion of lytic enzymes is known as an important way to prevent phytopathogens from living in the region of the rhizosphere. Rhizosphere microorganism produces chitinases, cellulases, proteases, and glucanases in reaction to phytopathogen assault. For assessing antagonist-pathogen interactions, ecological characteristics of antagonists in the rhizosphere, and optimizing the effectiveness of bacterial, fungal, and viral biocontrol agents, new molecular approaches have become available. Given the experience of fungicides in near future, biological management would be another method to control diseases of plant. Since agro-ecosystem is a flexible and functioning structure that involves many variables that affect disease and production of crop, other IPM methods to control diseases of crop are also important in different surrounding conditions. As result, to successfully minimize disease production and crop yield loss in various crop systems, other IPM management mechanisms other than biological control should be considered and implemented.

Tailoring Next Generation Plant Growth Promoting Microorganisms as Versatile Tools beyond Soil Desalinization: A Road Map towards Field Application

Plant growth promoting bacteria (PGPB) have been the target of intensive research studies toward their efficient use in the field as biofertilizers, biocontrol, and bioremediation agents among numerous other applications. Recent trends in the field of PGPB research led to the development of versatile multifaceted PGPB that can be used in different field conditions such as biocontrol of plant pathogens in metal contaminated soils. Unfortunately, all these research efforts lead to the development of PGPB that failed to perform in salty environments. Therefore, it is urgently needed to address this drawback of these PGPB toward their efficient performance in salinity context. In this paper we provide a review of state-of-the-art research in the field of PGPB and propose a road map for the development of next generation versatile and multifaceted PGPB that can perform in salinity. Beyond soil desalinization, our study paves the way towards the development of PGPB able to provide services in diverse salty environments such as heavy metal contaminated, or pathogen threatened. Smart development of salinity adapted next generation biofertilizers will inevitably allow for mitigation and alleviation of biotic and abiotic threats to plant productivity in salty environments.