A window into fungal endophytism in Salicornia europaea: deciphering fungal characteristics as plant growth promoting agents

Abstract Aim Plant-endophytic associations exist only when equilibrium is maintained between both partners. This study analyses the properties of endophytic fungi inhabiting a halophyte growing in high soil salinity and tests whether these fungi are beneficial or detrimental when non-host plants are inoculated. Method Fungi were isolated from Salicornia europaea collected from two sites differing in salinization history (anthropogenic and naturally saline) and analyzed for plant growth promoting abilities and non-host plant interactions. Results Most isolated fungi belonged to Ascomycota (96%) including dematiaceous fungi and commonly known plant pathogens and saprobes. The strains were metabolically active for siderophores, polyamines and indole-3-acetic acid (mainly Aureobasidium sp.) with very low activity for phosphatases. Many showed proteolytic, lipolytic, chitinolytic, cellulolytic and amylolytic activities but low pectolytic activity. Different activities between similar fungal species found in both sites were particularly seen for Epiccocum sp., Arthrinium sp. and Trichoderma sp. Inoculating the non-host Lolium perenne with selected fungi increased plant growth, mainly in the symbiont (Epichloë)-free variety. Arthrinium gamsii CR1-9 and Stereum gausapatum ISK3-11 were most effective for plant growth promotion. Conclusions This research suggests that host lifestyle and soil characteristics have a strong effect on endophytic fungi, and environmental stress could disturb the plant-fungi relations. In favourable conditions, these fungi may be effective in facilitating crop production in non-cultivable saline lands.

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Diversity, biocontrol, and growth promotion potential of culturable endophytic fungi isolated from root, shoot, and leaf of wild Phoebe bournei (Hemsl.) Yang across the seasons

Canadian Journal of Forest Research ◽

10.1139/cjfr-2021-0078 ◽

2021 ◽

Author(s):

Cun Yu ◽

Ying Yao

Keyword(s):

Plant Growth ◽

Endophytic Fungi ◽

Plant Pathogens ◽

Growth Promotion ◽

Leaf Spot Disease ◽

Plant Growth Promoting Activities ◽

Potential Applicability ◽

Plant Growth Promoting ◽

Growth Promoting ◽

Phoebe Bournei

Endophytic fungi were isolated from Phoebe bournei and their diversity and antimicrobial and plant growth-promoting activities were investigated. Of the 389 isolated endophytic fungi, 88.90% belonged to phylum Ascomycota and 11.10% to phylum Basidiomycota. The isolates were grouped into four taxonomic classes, 11 orders, 30 genera, and 45 species based on internal transcribed spacer sequencing and morphologic analysis. The host showed a strong affinity for the genera Diaporthe and Phyllosticta. The diversity of the fungi was highest in autumn, followed by spring and summer, and was lowest in winter. The fungi exhibited notable tissue specificity in P. bournei, and the species richness and diversity were highest in the root across all seasons. Five isolates showed antimicrobial activity against eight plant pathogens, and reduced the incidence of leaf spot disease in P. bournei. Additionally, 9 biocontrol isolates showed plant growth-promoting activity, with five significantly promoting P. bournei seedling growth. This is the first report on the endophytic fungi of P. bournei and their potential applicability to plant disease control and growth promotion.

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Genomic Mining and Physiological Characterization of new Halophilic Plant Growth Promoting Bacilli

10.1101/2021.05.17.444429 ◽

2021 ◽

Author(s):

Claudia Petrillo ◽

Stefany Castaldi ◽

Mariamichela Lanzilli ◽

Matteo Selci ◽

Angelina Cordone ◽

...

Keyword(s):

Plant Growth ◽

Crop Production ◽

Growth Promotion ◽

Biological Activities ◽

Gene Clusters ◽

Plant Growth Promoting Bacteria ◽

Dual Culture ◽

Whole Genome Analysis ◽

Plant Growth Promoting ◽

Growth Promoting

Massive application of chemical fertilizers and pesticides has been the main strategy used to cope with the rising crop demands in the last decades. The indiscriminate use of chemicals while providing a temporary solution has led to a decrease in crop productivity and an increase in the environmental impact of modern agriculture. A sustainable alternative to the use of chemicals for crop production is the use of microorganisms naturally capable of enhancing plant growth and protecting crops from pests, known as Plant-Growth-Promoting Bacteria (PGPB). The aim of the present study was to isolate and characterize PGPB from salt-pans sand samples able to ameliorate plant fitness. To survive high salinity, salt-tolerant microbes produce a broad range of compounds with heterogeneous biological activities that are potentially beneficial for plant growth. We have isolated and screened in vitro a total of 20 halophilic spore-forming bacteria for phyto-beneficial traits and compared the results with two rhizosphere Bacilli recently isolated from the rhizosphere of the same collection site and recently characterized as potential biocontrol agents. Whole-genome analysis on five selected halophilic strains confirmed the presence of numerous gene clusters with PGP and biocontrol functions and of novel secondary-metabolite biosynthetic genes potentially involved in plant growth promotion and protection. The predicted biocontrol potential was confirmed in dual culture assays against several phytopathogenic fungi and bacteria. Interestingly, the absence of predicted gene clusters with known biocontrol functions in some of the isolates was not predictive of the in vivo results, supporting the need of combining laboratory assays and genome mining in PGPB identification for future applications.

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Importance of plant growth promoting rhizobacteria (PGPR) in agriculture: A Review

Bhartiya Krishi Anusandhan Patrika ◽

10.18805/bkap200 ◽

2020 ◽

Vol 35 (1-2) ◽

Author(s):

Tabish Akhtar ◽

Shubham Kumar ◽

Sukhdeo Kumar ◽

M. R. Meena

Keyword(s):

Plant Growth ◽

Crop Production ◽

Plant Pathogens ◽

Crop Yields ◽

Plant Growth Promoting Rhizobacteria ◽

Agricultural Industry ◽

Plant Growth Promoting ◽

Growth Promoting ◽

Increasing Demand ◽

Environmentally Sound

The growth of plants promoting rhizobacteria (PGPR) has gained widespread importance in agriculture. These are beneficial bacteria found in nature that live actively in plant roots and improve plant growth and increase agricultural productivity.. (PGPR) promoting plant growth shows an important role in the sustainable agricultural industry. The increasing demand for crop production is a major challenge nowadays, with a significant lack of use of synthetic chemical fertilizers and pesticides. The use of PGPR has proven to be an environmentally sound way of increasing crop yields by facilitating plant growth through direct or indirect mechanisms. The mechanisms of PGPR include regulating hormonal and nutritional balance, inducing resistance against plant pathogens, and dissolving nutrients for easy uptake by plants. Furthermore, PGPRs show synergistic and antagonistic interactions with microorganisms within the rhizosphere and in bulk soils, which indirectly increases plant growth rates. There are several bacteria species that act as PGPR. This review summarizes the methodology of PGPR as a bio-fertilizer in agriculture.

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Isolation, selection, and characterization of beneficial rhizobacteria from pea, lentil, and chickpea grown in western Canada

Canadian Journal of Microbiology ◽

10.1139/w08-008 ◽

2008 ◽

Vol 54 (4) ◽

pp. 248-258 ◽

Cited By ~ 72

Author(s):

Russell K. Hynes ◽

Grant C.Y. Leung ◽

Danielle L.M. Hirkala ◽

Louise M. Nelson

Keyword(s):

Plant Growth ◽

Plant Growth Promotion ◽

Fungal Pathogens ◽

Crop Production ◽

Growth Promotion ◽

Profile Analysis ◽

Acc Deaminase ◽

Plant Growth Promoting ◽

Growth Promoting

The use of beneficial soil microorganisms as agricultural inputs for improved crop production requires selection of rhizosphere-competent microorganisms with plant growth-promoting attributes. A collection of 563 bacteria originating from the roots of pea, lentil, and chickpea grown in Saskatchewan was screened for several plant growth-promoting traits, for suppression of legume fungal pathogens, and for plant growth promotion. Siderophore production was detected in 427 isolates (76%), amino-cyclopropane-1-carboxylic acid (ACC) deaminase activity in 29 isolates (5%), and indole production in 38 isolates (7%). Twenty-six isolates (5%) suppressed the growth of Pythium sp. strain p88-p3, 40 isolates (7%) suppressed the growth of Fusarium avenaceum , and 53 isolates (9%) suppressed the growth of Rhizoctonia solani CKP7. Seventeen isolates (3%) promoted canola root elongation in a growth pouch assay, and of these, 4 isolates promoted the growth of lentil and one isolate promoted the growth of pea. Fatty acid profile analysis and 16S rRNA sequencing of smaller subsets of the isolates that were positive for the plant growth-promotion traits tested showed that 39%–42% were members of the Pseudomonadaceae and 36%–42% of the Enterobacteriaceae families. Several of these isolates may have potential for development as biofertilizers or biopesticides for western Canadian legume crops.

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Identification of Plant Growth Promoting Bacteria Within Space Crop Production Systems

Frontiers in Astronomy and Space Sciences ◽

10.3389/fspas.2021.735834 ◽

2021 ◽

Vol 8 ◽

Author(s):

David Handy ◽

Mary E. Hummerick ◽

Anirudha R. Dixit ◽

Anna Maria Ruby ◽

Gioia Massa ◽

...

Keyword(s):

Plant Growth ◽

Crop Production ◽

Plant Pathogens ◽

Life Support ◽

Production Systems ◽

Space Station ◽

Fungal Species ◽

Plant Growth Promoting Bacteria ◽

Plant Growth Promoting ◽

Growth Promoting

As we establish colonies beyond Earth, resupply missions will become increasingly difficult, logistically speaking, and less frequent. As a result, the on-site production of plants will be mission critical for both food production as well as complementing life support systems. Previous research on space crop production aboard the International Space Station (ISS) has determined that the spaceflight environment, though capable of supporting plant growth, is inherently stressful to plants. The combined stressors of this environment limits yield by inhibiting growth, as well as increasing susceptibility to infection by plant pathogens such as Fusarium spp. We propose that a consortium of space-viable, plant growth-promoting bacteria (PGPB) could assist in mitigating challenges to plant growth in a sustainable fashion. Here, we utilize biochemical and phenotypic assessments to identify potential PGPB derived from previously acquired isolates from the VEGGIE crop production system aboard the ISS. These assays confirmed the presence of bacteria capable of producing and/or interfering with plant hormones, facilitating plant uptake of high-value target nutrients for plants such as iron and phosphorus, and able to inhibit the growth of problematic fungal species. We discuss our findings with regards to their potential to support plant growth aboard spaceflight platforms as well as the Moon and Mars.

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Role of Plant Growth-Promoting Rhizobacteria (PGPR) and Bio-Control Agents (BCAs) in Crop Production

International Journal of Economic Plants ◽

10.23910/2/2020.0379 ◽

2020 ◽

Vol 7 (3) ◽

pp. 144-150

Author(s):

Sujata Kumari ◽

◽

Narender K. Bharat ◽

Ashok K. Thakur ◽

◽

...

Keyword(s):

Plant Growth ◽

Seed Treatment ◽

Crop Production ◽

Growth Promotion ◽

Plant Growth Promoting Rhizobacteria ◽

Plant Diseases ◽

Environment Friendly ◽

Plant Growth Promoting ◽

Growth Promoting

The bioagents like Plant Growth Promoting Rhizobacteria (PGPR) and Biocontrol Agents (BCAs) play a crucial role in plant growth promotion, nutrient uptake and suppression of biotic and abiotic stresses. Different researchers have applied these bioagents by various means either through seed treatment or through soil application to prevent various plant diseases. Thus, these non-chemical environment friendly tools can be exploited to enhance crop production.

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Silencing of Phytopathogen Communication by the Halotolerant PGPR Staphylococcus Equorum Strain EN21

Microorganisms ◽

10.3390/microorganisms8010042 ◽

2019 ◽

Vol 8 (1) ◽

pp. 42

Author(s):

Clara Vega ◽

Miguel Rodríguez ◽

Inmaculada Llamas ◽

Victoria Béjar ◽

Inmaculada Sampedro

Keyword(s):

Plant Growth ◽

Pseudomonas Syringae ◽

Plant Growth Promotion ◽

Crop Production ◽

Growth Promotion ◽

Signal Molecules ◽

Staphylococcus Equorum ◽

Plant Growth Promoting ◽

Growth Promoting

Increasing world food demand together with soil erosion and indiscriminate use of chemical fertilization highlight the need to adopt sustainable crop production strategies. In this context, a combination of plant growth-promoting rhizobacteria (PGPR) and pathogen management represents a sustainable and efficient alternative. Though little studied, halophilic and halotolerant PGPR could be a beneficial plant growth promotion strategy for saline and non-saline soils. The virulence of many bacterial phytopathogens is regulated by quorum sensing (QS) systems. Quorum quenching (QQ) involves the enzymatic degradation of phytopathogen-generated signal molecules, mainly N-acyl homoserine lactones (AHLs). In this study, we investigate plant growth-promoting (PGP) activity and the capacity of the halotolerant bacterium Staphylococcus equorum strain EN21 to attenuate phytopathogens virulence through QQ. We used biopriming and in vivo tomato plant experiments to analyse the PGP activity of strain EN21. AHL inactivation was observed to reduce Pseudomonas syringae pv. tomato infections in tomato and Arabidopsis plants. Our study of Dickeya solani, Pectobacterium carotovorum subsp. carotovorum and Erwinia amylovora bacteria in potato tubers, carrots and pears, respectively, also demonstrated the effectiveness of QS interruption by EN21. Overall, this study highlights the potential of strain S. equorum EN21 in plant growth promotion and QQ-driven bacterial phytopathogen biocontrol.

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Application and Mechanisms of Plant Growth Promoting Fungi (PGPF) for Phytostimulation

Organic Agriculture ◽

10.5772/intechopen.92338 ◽

2020 ◽

Cited By ~ 1

Author(s):

Md. Motaher Hossain ◽

Farjana Sultana

Keyword(s):

Plant Growth ◽

Sustainable Agriculture ◽

Crop Production ◽

Plant Pathogens ◽

Crop Yields ◽

Intrinsic Factor ◽

Beneficial Effects ◽

Plant Growth Promoting ◽

Growth Promoting ◽

Increasing Demand

Plant growth-promoting fungi (PGPF) constitute diverse genera of nonpathogenic fungi that provide a variety of benefits to their host plants. PGPF show an effective role in sustainable agriculture. Meeting increasing demand for crop production without damage to the environment is the biggest challenge nowadays. The use of PGPF has been recognized as an environmentally friendly way of increasing crop production. These fungi have proven to increase crop yields by improving germination, seedling vigor, plant growth, root morphogenesis, photosynthesis, and flowering through either a direct or indirect mechanism. The mechanisms of PGPF involve solubilizing and mineralizing nutrients for easy uptake by plants, regulating hormonal balance, producing volatile organic compounds and microbial enzyme, suppressing plant pathogens and ameliorating abiotic stresses. Successful colonization is an intrinsic factor for most PGPF to exert their beneficial effects on plants. A certain level of specificity exists in the interactions between plant species and PGPF for root colonization and growth promoting effects. There is a gap between the number of reported efficacious PGPF and the number of PGPF as biofertilizer. Efforts should be strengthened to improve the efficacy and commercialization of PGPF. Hence, this chapter summarizes valuable information regarding the application and mechanisms of PGPF in sustainable agriculture.

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Plant growth promoting rhizobacteria isolated from halophytes and drought-tolerant plants: genomic characterisation and exploration of phyto-beneficial traits

Scientific Reports ◽

10.1038/s41598-020-71652-0 ◽

2020 ◽

Vol 10 (1) ◽

Cited By ~ 1

Author(s):

Kleopatra Leontidou ◽

Savvas Genitsaris ◽

Anastasia Papadopoulou ◽

Nathalie Kamou ◽

Irene Bosmali ◽

...

Keyword(s):

Plant Growth ◽

Crop Production ◽

Growth Promotion ◽

Plant Growth Promoting Rhizobacteria ◽

Gene Clusters ◽

Stress Factors ◽

Wild Plant ◽

Whole Genome Analysis ◽

Plant Growth Promoting ◽

Growth Promoting

Abstract Plant growth promoting rhizobacteria (PGPR) are able to provide cross-protection against multiple stress factors and facilitate growth of their plant symbionts in many ways. The aim of this study was to isolate and characterize rhizobacterial strains under natural conditions, associated with naturally occurring representatives of wild plant species and a local tomato cultivar, growing in differently stressed Mediterranean ecosystems. A total of 85 morphologically different rhizospheric strains were isolated; twenty-five exhibited multiple in vitro PGP-associated traits, including phosphate solubilization, indole-3-acetic acid production, and 1-aminocyclopropane-1-carboxylate deaminase activity. Whole genome analysis was applied to eight selected strains for their PGP potential and assigned seven strains to Gammaproteobacteria, and one to Bacteroidetes. The genomes harboured numerous genes involved in plant growth promotion and stress regulation. They also support the notion that the presence of gene clusters with potential PGP functions is affirmative but not necessary for a strain to promote plant growth under abiotic stress conditions. The selected strains were further tested for their ability to stimulate growth under stress. This initial screening led to the identification of some strains as potential PGPR for increasing crop production in a sustainable manner.

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Pathogen Biocontrol Using Plant Growth-Promoting Bacteria (PGPR): Role of Bacterial Diversity

Microorganisms ◽

10.3390/microorganisms9091988 ◽

2021 ◽

Vol 9 (9) ◽

pp. 1988

Author(s):

Hao Wang ◽

Runjin Liu ◽

Ming Pei You ◽

Martin J. Barbetti ◽

Yinglong Chen

Keyword(s):

Plant Growth ◽

Plant Pathogens ◽

Growth Promotion ◽

Plant Growth Promoting Rhizobacteria ◽

Disease Suppression ◽

Plant Growth Promoting Bacteria ◽

Critical Determinant ◽

Plant Growth Promoting ◽

Growth Promoting ◽

Plant Disease Management

A vast microbial community inhabits in the rhizosphere, among which, specialized bacteria known as Plant Growth-Promoting Rhizobacteria (PGPR) confer benefits to host plants including growth promotion and disease suppression. PGPR taxa vary in the ways whereby they curtail the negative effects of invading plant pathogens. However, a cumulative or synergistic effect does not always ensue when a bacterial consortium is used. In this review, we reassess the disease-suppressive mechanisms of PGPR and present explanations and illustrations for functional diversity and/or stability among PGPR taxa regarding these mechanisms. We also provide evidence of benefits when PGPR mixtures, rather than individuals, are used for protecting crops from various diseases, and underscore the critical determinant factors for successful use of PGPR mixtures. Then, we evaluate the challenges of and limitations to achieving the desired outcomes from strain/species-rich bacterial assemblages, particularly in relation to their role for plant disease management. In addition, towards locating additive or synergistic outcomes, we highlight why and how the benefits conferred need to be categorized and quantified when different strains/species of PGPR are used in combinations. Finally, we highlight the critical approaches needed for developing PGPR mixtures with improved efficacy and stability as biocontrols for utilization in agricultural fields.

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