Bacterial endophytes in agricultural crops

1997 ◽  
Vol 43 (10) ◽  
pp. 895-914 ◽  
Author(s):  
J. Hallmann ◽  
A. Quadt-Hallmann ◽  
W. F. Mahaffee ◽  
J. W. Kloepper
Keyword(s):  
Endophytic Bacteria ◽  
Plant Pathogens ◽  
Growth Promotion ◽  
Abiotic Factors ◽  
Hydrolytic Enzymes ◽  
Dynamic Structure ◽  
Plant Tissues ◽  
Beneficial Effects ◽  
Weakly Virulent ◽  
Planting Materials

Endophytic bacteria are ubiquitous in most plant species, residing latently or actively colonizing plant tissues locally as well as systemically. Several definitions have been proposed for endophytic bacteria; in this review endophytes will be defined as those bacteria that can be isolated from surface-disinfested plant tissue or extracted from within the plant, and that do not visibly harm the plant. While this definition does not include nonextractable endophytic bacteria, it is a practical definition based on experimental limitations and is inclusive of bacterial symbionts, as well as internal plant-colonizing nonpathogenic bacteria with no known beneficial or detrimental effects on colonized plants. Historically, endophytic bacteria have been thought to be weakly virulent plant pathogens but have recently been discovered to have several beneficial effects on host plants, such as plant growth promotion and increased resistance against plant pathogens and parasites. In general, endophytic bacteria originate from the epiphytic bacterial communities of the rhizosphere and phylloplane, as well as from endophyte-infested seeds or planting materials. Besides gaining entrance to plants through natural openings or wounds, endophytic bacteria appear to actively penetrate plant tissues using hydrolytic enzymes like cellulase and pectinase. Since these enzymes are also produced by pathogens, more knowledge on their regulation and expression is needed to distinguish endophytic bacteria from plant pathogens. In general, endophytic bacteria occur at lower population densities than pathogens, and at least some of them do not induce a hypersensitive response in the plant, indicating that they are not recognized by the plant as pathogens. Evolutionarily, endophytes appear to be intermediate between saprophytic bacteria and plant pathogens, but it can only be speculated as to whether they are saprophytes evolving toward pathogens, or are more highly evolved than plant pathogens and conserve protective shelter and nutrient supplies by not killing their host. Overall, the endophytic microfloral community is of dynamic structure and is influenced by biotic and abiotic factors, with the plant itself constituting one of the major influencing factors. Since endophytic bacteria rely on the nutritional supply offered by the plant, any parameter affecting the nutritional status of the plant could consequently affect the endophytic community. This review summarizes part of the work being done on endophytic bacteria, including their methodology, colonization, and establishment in the host plant, as well as their role in plant–microbe interactions. In addition, speculative conclusions are raised on some points to stimulate thought and research on endophytic bacteria.Key words: endophytic bacteria, methods, localization, diversity, biological control.

scholarly journals Endospore-Forming Bacteria Present in a Commercial Stabilized Poultry Manure Determines the Fusarium Biocontrol and the Tomato Growth Promotion

Agronomy ◽  
2020 ◽  
Vol 10 (11) ◽  
pp. 1636
Author(s):  
German F. Sepúlveda Chavera ◽  
Mabel Arismendi Macuer ◽  
Patricio Muñoz Torres
Keyword(s):  
Plant Pathogens ◽  
Growth Promotion ◽  
Growth Parameters ◽  
Poultry Manure ◽  
Organic Amendments ◽  
Rrna Gene ◽  
Biochemical Tests ◽  
Tomato Cultivar ◽  
Beneficial Effects ◽  
Bacillus Spp

Stabilized organic amendments (SOA) from poultry are used in agriculture to improve the conditions of the soil. SOAs favor the growth of the crops and reduces the effect of soil-borne plant-pathogens. However, in northern Chile, there are no studies to support this observation, nor have the mechanisms involved in the beneficial effects observed in the field been established. This work aims to establish whether the promotion of growth and control of soil fungi in tomato observed in the field as a result of commercial SOA application can be attributed to different endospore-forming bacteria (EFB). The effect of commercial SOA on nutrient availability was determined. EFB isolated from a commercial product, and the application of bacterial isolates were compared with the commercial formulation of SOA, for plant growth promotion (PGP) and biocontrol of Fusarium oxysporum fsp. radicis-lycopersici (FORL). The local tomato cultivar Poncho Negro was used given its sensitivity to different nutritional alterations and FORL. A series of measurements of growth parameters were carried out in plants submitted to different mixtures of SOA treatments. Isolates were identified by biochemical tests and sequencing of the 16S rRNA gene. Eleven EFB were isolated from SOA, and some tests were performed to determine the PGP and biocontrol of FORL activities of each isolate. Notably, isolates BAC22 (Bacillusmegaterium), BAC21, and BAC23 (B. amyloliquefaciens/velezencis) were associated with PGP, highlighting the ability to produce indole-3-acetic acid, a trait that in many cases is key to explaining the effects of Bacillus spp.

scholarly journals The Endophytic Microbiome as a Hotspot of Synergistic Interactions, with Prospects of Plant Growth Promotion

Biology ◽  
2021 ◽  
Vol 10 (2) ◽  
pp. 101
Author(s):  
Udaya Kumar Vandana ◽  
Jina Rajkumari ◽  
L. Paikhomba Singha ◽  
Lakkakula Satish ◽  
Hemasundar Alavilli ◽  
...  
Keyword(s):  
Plant Growth ◽  
Microbial Communities ◽  
Plant Growth Promotion ◽  
Endophytic Bacteria ◽  
Host Plants ◽  
Plant Pathogens ◽  
Growth Promotion ◽  
Plant Root ◽  
Endophytic Microorganisms ◽  
Microbe Interactions

The plant root is the primary site of interaction between plants and associated microorganisms and constitutes the main components of plant microbiomes that impact crop production. The endophytic bacteria in the root zone have an important role in plant growth promotion. Diverse microbial communities inhabit plant root tissues, and they directly or indirectly promote plant growth by inhibiting the growth of plant pathogens, producing various secondary metabolites. Mechanisms of plant growth promotion and response of root endophytic microorganisms for their survival and colonization in the host plants are the result of complex plant-microbe interactions. Endophytic microorganisms also assist the host to sustain different biotic and abiotic stresses. Better insights are emerging for the endophyte, such as host plant interactions due to advancements in ‘omic’ technologies, which facilitate the exploration of genes that are responsible for plant tissue colonization. Consequently, this is informative to envisage putative functions and metabolic processes crucial for endophytic adaptations. Detection of cell signaling molecules between host plants and identification of compounds synthesized by root endophytes are effective means for their utilization in the agriculture sector as biofertilizers. In addition, it is interesting that the endophytic microorganism colonization impacts the relative abundance of indigenous microbial communities and suppresses the deleterious microorganisms in plant tissues. Natural products released by endophytes act as biocontrol agents and inhibit pathogen growth. The symbiosis of endophytic bacteria and arbuscular mycorrhizal fungi (AMF) affects plant symbiotic signaling pathways and root colonization patterns and phytohormone synthesis. In this review, the potential of the root endophytic community, colonization, and role in the improvement of plant growth has been explained in the light of intricate plant-microbe interactions.

Pathogenicity and biotechnological applications of the genus Burkholderia

2011 ◽  
Vol 6 (6) ◽  
pp. 997-1005 ◽  
Author(s):  
Patrizia Paganin ◽  
Silvia Tabacchioni ◽  
Luigi Chiarini
Keyword(s):  
Burkholderia Cepacia ◽  
Burkholderia Pseudomallei ◽  
Plant Pathogens ◽  
Growth Promotion ◽  
Burkholderia Cepacia Complex ◽  
Plant Tissues ◽  
Biotechnological Applications ◽  
Burkholderia Glumae ◽  
The Past ◽  
Potential Use

AbstractBacteria belonging to the genus Burkholderia are well known for their adaptability to habitats as diverse as freshwater sediments, lungs of cystic fibrosis patients and plant tissues. This genus includes also plant, animal and human pathogenic species, such as Burkholderia glumae, Burkholderia pseudomallei and the Burkholderia cepacia complex. Over the past few years, several newly discovered non-pathogenic plant associated Burkholderia species have raised particular interest for their potential use in plant growth promotion, biocontrol of plant pathogens, phytoremediation and xenobiotics degradation. Highlights from recent studies on the taxonomy, ecology and pathogenicity of different species of the Burkholderia genus are presented with the aim to evaluate their potential use in biotechnology.

scholarly journals Diversity and Taxonomic Distribution of Endophytic Bacterial Community in the Rice Plant and Its Prospective

2021 ◽  
Vol 22 (18) ◽  
pp. 10165
Author(s):  
Mohsin Ali ◽  
Qurban Ali ◽  
Muhammad Aamir Sohail ◽  
Muhammad Furqan Ashraf ◽  
Muhammad Hamzah Saleem ◽  
...  
Keyword(s):  
Plant Growth ◽  
Sustainable Agriculture ◽  
Bacterial Communities ◽  
Endophytic Bacteria ◽  
Rice Plant ◽  
Growth Promotion ◽  
Plant Tissues ◽  
Taxonomic Distribution ◽  
Rice Plants ◽  
Agriculture Systems

Endophytic bacterial communities are beneficial communities for host plants that exist inside the surfaces of plant tissues, and their application improves plant growth. They benefit directly from the host plant by enhancing the nutrient amount of the plant’s intake and influencing the phytohormones, which are responsible for growth promotion and stress. Endophytic bacteria play an important role in plant-growth promotion (PGP) by regulating the indirect mechanism targeting pest and pathogens through hydrolytic enzymes, antibiotics, biocontrol potential, and nutrient restriction for pathogens. To attain these benefits, firstly bacterial communities must be colonized by plant tissues. The nature of colonization can be achieved by using a set of traits, including attachment behavior and motility speed, degradation of plant polymers, and plant defense evasion. The diversity of bacterial endophytes colonization depends on various factors, such as plants’ relationship with environmental factors. Generally, each endophytic bacteria has a wide host range, and they are used as bio-inoculants in the form of synthetic applications for sustainable agriculture systems and to protect the environment from chemical hazards. This review discusses and explores the taxonomic distribution of endophytic bacteria associated with different genotypes of rice plants and their origin, movement, and mechanism of PGP. In addition, this review accentuates compressive meta data of endophytic bacteria communities associated with different genotypes of rice plants, retrieves their plant-growth-promoting properties and their antagonism against plant pathogens, and discusses the indication of endophytic bacterial flora in rice plant tissues using various methods. The future direction deepens the study of novel endophytic bacterial communities and their identification from rice plants through innovative techniques and their application for sustainable agriculture systems.

scholarly journals Identification and determination of characteristics of endophytes from rice plants and their role in biocontrol of bacterial blight caused by Xanthomonas oryzae pv. oryzae

2018 ◽  
Vol 11 (1) ◽  
pp. 19-33 ◽  
Author(s):  
H. Yousefi ◽  
N. Hassanzadeh ◽  
K. Behboudi ◽  
F. Beiki Firouzjahi
Keyword(s):  
Plant Growth ◽  
Endophytic Bacteria ◽  
Plant Pathogens ◽  
Growth Promotion ◽  
Antagonistic Activity ◽  
Xanthomonas Oryzae ◽  
Rice Plants ◽  
16S Rdna Sequence Analysis ◽  
North Of Iran ◽  
Plant Growth Promoting

SummaryEndophytic bacteria of rice plants (Oryza sativaL.) from eight different cultivars were screened for their ability in inducing disease symptoms, plant growth promotion and antagonistic activity againstXanthomonas oryzaepv.oryzae.Out of the 63 whole isolates, five were plant pathogens. Based on phenotypic characteristics and 16S rDNA sequence analysis, these were identified asPseudomonas oryzihabitans,P. fulva,Pantoea ananatis,Pantoeasp.,Cellulomonassp. Four out of the 63 isolates behaved as potentially good plant growth-promoting and biocontrol agents. These were identified asBacillussp.,B. subtilis,Pseudomonas putidaandEnterobactersp. This is the first report of pathogenic and endophytic bacteria from rice grown in field conditions in North of Iran.

scholarly journals Diversity and biological activity of culturable endophytic bacteria associated with marigold (Calendula officinalis L.)

2021 ◽  
Vol 7 (3) ◽  
pp. 336-353
Author(s):  
Vyacheslav Shurigin ◽  
◽  
Burak Alaylar ◽  
Kakhramon Davranov ◽  
Stephan Wirth ◽  
...  
Keyword(s):  
Plant Growth ◽  
Endophytic Bacteria ◽  
Plant Pathogens ◽  
Hydrolytic Enzymes ◽  
Pathogenic Fungi ◽  
Rrna Gene ◽  
Plant Pathogenic Fungi ◽  
Bacterial Isolates ◽  
Calendula Officinalis ◽  
Fungal Plant Pathogens

<abstract> <p>Endophytes colonizing plant tissue play an essential role in plant growth, development, stress tolerance and plant protection from soil-borne diseases. In this study, we report the diversity of cultivable endophytic bacteria associated with marigold (<italic>Calendula officinalis</italic> L.) by using 16S rRNA gene analysis and their plant beneficial properties. A total of 42 bacterial isolates were obtained from plant tissues of marigold. They belonged to the genera <italic>Pantoea, Enterobacter, Pseudomonas, Achromobacter, Xanthomonas, Rathayibacter, Agrobacterium, Pseudoxanthomonas</italic>, and <italic>Beijerinckia</italic>. Among the bacterial strains, <italic>P. kilonensis</italic> FRT12, and <italic>P. rhizosphaerae</italic> FST5 showed moderate or vigorous inhibition against three tested plant pathogenic fungi, <italic>F. culmorum, F. solani</italic> and <italic>R. solani</italic>. They also demonstrated the capability to produce hydrolytic enzymes and indole-3-acetic acid (IAA). Five out of 16 isolates significantly stimulated shoot and root growth of marigold in a pot experiment. The present study reveals that more than half of the bacterial isolates associated with marigold (<italic>C. officinalis</italic> L.) provided antifungal activity against one or more plant pathogenic fungi. Our findings suggest that medicinal plants with antimicrobial activity could be a source for selecting microbes with antagonistic activity against fungal plant pathogens or with plant growth stimulating potential. These isolates might be considered as promising candidates for the improvement of plant health.</p> </abstract>

scholarly journals Soil Bacteria as Potential Biological Control Agents of Fusarium Species Associated with Asparagus Decline Syndrome

2021 ◽  
Vol 11 (18) ◽  
pp. 8356
Author(s):  
Eduardo De la Lastra ◽  
María Camacho ◽  
Nieves Capote
Keyword(s):  
Plant Growth ◽  
Protective Effect ◽  
Plant Pathogens ◽  
Growth Promotion ◽  
Fusarium Species ◽  
Control Plant ◽  
Hydrolytic Enzymes ◽  
Biocontrol Agents ◽  
Alternative Methods ◽  
Mycelium Growth

To avoid the use of agrochemicals in agriculture, alternative methods are emerging to control plant pathogens. Some plant growth-promoting rhizobacteria (PGPR) can be used as biocontrol agents since they can induce protection against pathogens. The aim of this study was to evaluate the protective effect of several PGPR strains against the main Fusarium species involved in asparagus decline syndrome (ADS): F. proliferatum, F. oxysporum f. sp. asparagi and F. redolens. In vitro antagonism assays showed that all the bacteria inhibited the mycelium growth of the three Fusarium species. The most effective strains (Streptomyces fradiae Hvs6, Bacillus paralicheniformis Hvs2 and Bacillus velezensis FC37) were tested to evaluate their protective effect on asparagus plants inoculated with pathogenic Fusarium isolates. Strains FC37 and Hvs2 were the most effective in controlling pathogenic F. proliferatum and F. oxysporum f. sp. asparagi, but neither could protect against F. redolens isolates. The production of hydrolytic enzymes such as β-glucosidase, amylase and protease by these bacterial strains could be involved in the structural degradation of the fungal cell wall. In addition, the production of toxic volatile compounds, such as hydrogen cyanide, may inhibit the fungal growth, and the production of phosphate solubilizers could be related to the plant growth promotion. These results suggest that strains FC37 and Hvs2 could be used as potential biocontrol agents as a sustainable and environmentally friendly control strategy for ADS-affected fields.

scholarly journals Opprimo ergo sum—Evasion and Suppression in the Root Endophytic Fungus Piriformospora indica

2012 ◽  
Vol 25 (6) ◽  
pp. 727-737 ◽  
Author(s):  
Urs Lahrmann ◽  
Alga Zuccaro
Keyword(s):  
Endophytic Fungus ◽  
Large Scale ◽  
Growth Promotion ◽  
Plant Root ◽  
Hydrolytic Enzymes ◽  
Piriformospora Indica ◽  
Host Cells ◽  
Suitable Model ◽  
Beneficial Effects ◽  
Small Proteins

The genetically tractable endophytic fungus Piriformospora indica is able to colonize the root cortex of a great variety of different plant species with beneficial effects to its hosts, and it represents a suitable model system to study symbiotic interactions. Recent cytological studies in barley and Arabidopsis showed that, upon penetration of the root, P. indica establishes a biotrophic interaction during which fungal cells are encased by the host plasma membrane. Large-scale transcriptional analyses of fungal and plant responses have shown that perturbance of plant hormone homeostasis and secretion of fungal lectins and other small proteins (effectors) may be involved in the evasion and suppression of host defenses at these early colonization steps. At later stages, P. indica is found more often in moribund host cells where it secretes a large variety of hydrolytic enzymes that degrade proteins. This strategy of colonizing plants is reminiscent of that of hemibiotrophic fungi, although a defined shift to necrotrophy with massive host cell death is missing. Instead, the association with the plant root leads to beneficial effects for the host such as growth promotion, increased resistance to root as well as leaf pathogens, and increased tolerance to abiotic stresses. This review describes current advances in understanding the components of the P. indica endophytic lifestyle from molecular and genomic analyses.

Associated microflora of medicinal ferns: biotechnological potentials and possible applications

2016 ◽  
Vol 5 (03) ◽  
pp. 4927 ◽  
Author(s):  
Shubhi Srivastava ◽  
Paul A. K.
Keyword(s):  
Secondary Metabolites ◽  
Growth Promotion ◽  
Biological Activities ◽  
Hydrolytic Enzymes ◽  
In Vitro Production ◽  
Wide Range ◽  
Negative Effect ◽  
Bacteria And Fungi

Plant associated microorganisms that colonize the upper and internal tissues of roots, stems, leaves and flowers of healthy plants without causing any visible harmful or negative effect on their host. Diversity of microbes have been extensively studied in a wide variety of vascular plants and shown to promote plant establishment, growth and development and impart resistance against pathogenic infections. Ferns and their associated microbes have also attracted the attention of the scientific communities as sources of novel bioactive secondary metabolites. The ferns and fern alleles, which are well adapted to diverse environmental conditions, produce various secondary metabolites such as flavonoids, steroids, alkaloids, phenols, triterpenoid compounds, variety of amino acids and fatty acids along with some unique metabolites as adaptive features and are traditionally used for human health and medicine. In this review attention has been focused to prepare a comprehensive account of ethnomedicinal properties of some common ferns and fern alleles. Association of bacteria and fungi in the rhizosphere, phyllosphere and endosphere of these medicinally important ferns and their interaction with the host plant has been emphasized keeping in view their possible biotechnological potentials and applications. The processes of host-microbe interaction leading to establishment and colonization of endophytes are less-well characterized in comparison to rhizospheric and phyllospheric microflora. However, the endophytes are possessing same characteristics as rhizospheric and phyllospheric to stimulate the in vivo synthesis as well as in vitro production of secondary metabolites with a wide range of biological activities such as plant growth promotion by production of phytohormones, siderophores, fixation of nitrogen, and phosphate solubilization. Synthesis of pharmaceutically important products such as anticancer compounds, antioxidants, antimicrobials, antiviral substances and hydrolytic enzymes could be some of the promising areas of research and commercial exploitation.

Dynamics of fungal pathogens in host plant tissues

1995 ◽  
Vol 73 (S1) ◽  
pp. 1275-1283 ◽  
Author(s):  
Shigehito Takenaka
Keyword(s):  
Host Plant ◽  
Species Interactions ◽  
Fungal Biomass ◽  
Quantitative Methods ◽  
Plant Pathogens ◽  
Pathogenic Fungi ◽  
Molecular Methods ◽  
Plant Colonization ◽  
Fungal Colonization ◽  
Plant Tissues

To develop efficient control measures against fungal plant pathogens, the dynamics of host plant colonization during disease development and the interactions among fungi within host plant tissues need to be clarified. These studies require accurate quantitative estimation of specific fungal biomass in plant tissues. This has been approached by direct-microscopic methods, cultural methods, chemical determinations of fungal components, serological methods, and molecular methods. Among these methods, serological and molecular methods provide rapid, specific, and sensitive quantitative measures of fungal biomass in host plant tissues. Therefore, studies on fungal dynamics of host plant colonization using these two methods are presented. Some examples of species interactions among pathogenic fungi within host plants, such as synergism and competition, are reviewed and the usefulness of serological and molecular methods for studies on these interactions is presented. These quantitative methods will provide helpful information for understanding the ecology of plant pathogenic fungi, such as the dynamics of host plant colonization and species interactions. Key words: quantitative methods, fungal biomass, ELISA, PCR, fungal colonization, species interaction.

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