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

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.

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Diversity and Functionality of Seed Vectored Bacterial Endophytes in Different Cultivars of Triticum Aestivum L. Across Ecological Boundaries

10.21203/rs.3.rs-989999/v1 ◽

2021 ◽

Author(s):

Jogdande SaiPrasad ◽

Archna Suman ◽

B. Ramakrishnan ◽

K. Aswini

Keyword(s):

Plant Growth ◽

Microbial Communities ◽

Plant Growth Promotion ◽

Enzyme Production ◽

Plant Pathogens ◽

Growth Promotion ◽

Horizontal Transmission ◽

Hydrolytic Enzyme ◽

Priority Effects ◽

Production Plant

Abstract The endophytic microbial communities of plant seeds are either early or late colonizers, from the vascular system and stigma of mother plants or through contact from the environmental niches. Microbial communities get established in the plant progenies, particularly seeds, by vertical or horizontal transmission. The composition of seed microbiome determines the type of microbial associations, ranging from mutualism to pathogenicity with the emerging plants and also, the environmental conditions have a significant effect on their diversity. Wheat associated microbiota, especially rhizobacteria and endophytes from different plant organs possess competencies for plant growth promotion, and mitigation of abiotic and biotic stress. Improved yield and adaptation, as well as sustained wheat production across different ecologies necessitate the microbiome basis for understanding the genotype-environment (G×E) interactions. Hence,we investigated the diversity and functions of culturable endophytes from different ecological conditions on seed germination and the growth and fitness of plants. The core culturable microbiome members associated with seeds were identified, and evaluated for their potential for application and ensuing colonization in wheat plants.The diversity indices such as Shannon diversity (H), Chao1, Simpson’s reciprocal index and Species evenness (J) were generally highest in the PZ, followed by the NHZ. Likewise,this study showed that the genotypes play a profound role in their diversity, with variations in the hydrolytic enzyme production, plant growth promotion and priority effects on seedling colonization of wheat. The potential for hydrolytic enzyme production also suggest the multifarious mechanisms mediated by these endophytic bacteria for colonization and antagonism against plant pathogens.

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Isolation of phosphate solubilizing endophytic bacteria from Phyllanthus amarus Schum & Thonn: Evaluation of plant growth promotion and antioxidant activity under salt stress

Journal of Applied Research on Medicinal and Aromatic Plants ◽

10.1016/j.jarmap.2016.02.003 ◽

2016 ◽

Vol 3 (2) ◽

pp. 71-77 ◽

Cited By ~ 17

Author(s):

Manoharan Melvin Joe ◽

Shalini Devaraj ◽

Abitha Benson ◽

Tongmin Sa

Keyword(s):

Antioxidant Activity ◽

Salt Stress ◽

Plant Growth ◽

Plant Growth Promotion ◽

Endophytic Bacteria ◽

Growth Promotion ◽

Phyllanthus Amarus ◽

Phosphate Solubilizing

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Genome Sequencing of Pantoea agglomerans C1 Provides Insights into Molecular and Genetic Mechanisms of Plant Growth-Promotion and Tolerance to Heavy Metals

Microorganisms ◽

10.3390/microorganisms8020153 ◽

2020 ◽

Vol 8 (2) ◽

pp. 153 ◽

Cited By ~ 3

Author(s):

Francesca Luziatelli ◽

Anna Grazia Ficca ◽

Mariateresa Cardarelli ◽

Francesca Melini ◽

Andrea Cavalieri ◽

...

Keyword(s):

Heavy Metals ◽

Plant Growth ◽

Plant Growth Promotion ◽

Plant Pathogens ◽

Growth Promotion ◽

Pantoea Agglomerans ◽

Toxic Heavy Metals ◽

Circular Chromosome ◽

Plant Growth Promoting ◽

Genetic Mechanisms

Distinctive strains of Pantoea are used as soil inoculants for their ability to promote plant growth. Pantoea agglomerans strain C1, previously isolated from the phyllosphere of lettuce, can produce indole-3-acetic acid (IAA), solubilize phosphate, and inhibit plant pathogens, such as Erwinia amylovora. In this paper, the complete genome sequence of strain C1 is reported. In addition, experimental evidence is provided on how the strain tolerates arsenate As (V) up to 100 mM, and on how secreted metabolites like IAA and siderophores act as biostimulants in tomato cuttings. The strain has a circular chromosome and two prophages for a total genome of 4,846,925-bp, with a DNA G+C content of 55.2%. Genes related to plant growth promotion and biocontrol activity, such as those associated with IAA and spermidine synthesis, solubilization of inorganic phosphate, acquisition of ferrous iron, and production of volatile organic compounds, siderophores and GABA, were found in the genome of strain C1. Genome analysis also provided better understanding of the mechanisms underlying strain resistance to multiple toxic heavy metals and transmission of these genes by horizontal gene transfer. Findings suggested that strain C1 exhibits high biotechnological potential as plant growth-promoting bacterium in heavy metal polluted soils.

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Interactions between putatively endophytic bacteria and tall fescue (Festuca arundinacea): plant growth promotion and colonization in host and non-host cultivars

Plant and Soil ◽

10.1007/s11104-019-04359-5 ◽

2019 ◽

Vol 451 (1-2) ◽

pp. 207-220

Author(s):

Patricia Vaz Jauri ◽

Cecilia Taulé ◽

Maria Cecilia de los Santos ◽

Belén Fernandez ◽

Andrés Di Paolo ◽

...

Keyword(s):

Plant Growth ◽

Plant Growth Promotion ◽

Tall Fescue ◽

Festuca Arundinacea ◽

Endophytic Bacteria ◽

Growth Promotion

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Characterization of bacterial endophytes from the roots of native and cultivated Brazil nut trees (Bertholletia excelsa)

Acta Amazonica ◽

10.1590/1809-4392201804831 ◽

2019 ◽

Vol 49 (4) ◽

pp. 257-267

Author(s):

Patrícia Bombonati CHALITA ◽

Eliane do Nascimento Cunha FARIAS ◽

Ismaele Breckenfeld da COSTA ◽

Brenda Ferreira SOUSA ◽

Marco Antônio Oliveira dos SANTOS ◽

...

Keyword(s):

Plant Growth ◽

Plant Growth Promotion ◽

Endophytic Bacteria ◽

Growth Promotion ◽

Nifh Gene ◽

Aluminum Phosphate ◽

Brazil Nut ◽

Indole Compounds ◽

Plant Growth Promoting ◽

Growth Promoting

ABSTRACT Brazil nut is a very important nontimber forest product in the Amazon region. Propagation of this tree still represents a challenge due to slow and uneven seed germination. In this context, plant growth-promoting bacteria can facilitate the process of propagation. The aims of this study were to isolate and characterize endophytic bacteria from the roots of Brazil nut trees in native terra firme forest and cultivation areas in northern Brazil, and to identify mechanisms by which bacteria act in plant growth promotion. Overall, 90 bacterial isolates were obtained from the roots of Brazil nut trees in monoculture, agroforestry and native forest areas by using different semisolid media. The isolates were characterized by sequencing the 16S rRNA gene. Plant growth-promoting characteristics were evaluated by the presence of the nifH gene, aluminum phosphate solubilization and the production of indole compounds. The isolates were affiliated with 18 genera belonging to 5 different classes (α-Proteobacteria, β-Proteobacteria, γ-Proteobacteria, Bacilli and Actinobacteria). The genus Bacillus was predominant in the forest and monoculture areas. Fourteen isolates presented the nifH gene. Most of the bacteria were able to solubilize aluminum phosphate and synthetize indole compounds. The results indicated high diversity of endophytic bacteria present among the roots of Brazil nut trees, mainly in the agroforestry area, which could be related to soil attributes. Among the 90 isolates, the 22 that presented the best results regarding plant growth promotion traits were good candidates for testing in seedling production of Brazil nut trees.

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