Microorganisms

Research

17 pages, 4945 KiB

Open AccessArticle

Isolation and Characterization of Bacterial Endophytes from Small Nodules of Field-Grown Peanut

by Md Shakhawat Hossain, Christine Frith, Siddhartha Shankar Bhattacharyya, Paul B. DeLaune and Terry J. Gentry

Microorganisms 2023, 11(8), 1941; https://doi.org/10.3390/microorganisms11081941 - 29 Jul 2023

Viewed by 1706

Abstract

It is evident that legume root nodules can accommodate rhizobial and non-rhizobial bacterial endophytes. Our recent nodule microbiome study in peanuts described that small nodules can harbor diverse bacterial endophytes. To understand their functional role, we isolated 87 indigenous endophytes from small nodules [...] Read more.

It is evident that legume root nodules can accommodate rhizobial and non-rhizobial bacterial endophytes. Our recent nodule microbiome study in peanuts described that small nodules can harbor diverse bacterial endophytes. To understand their functional role, we isolated 87 indigenous endophytes from small nodules of field-grown peanut roots and characterized them at molecular, biochemical, and physiological levels. The amplified 16S rRNA genes and phylogenetic analysis of these isolates revealed a wide variety of microorganisms related to the genera Bacillus, Burkholderia, Enterobacter, Herbaspirillum, Mistsuaria, Pantoea, Pseudomonas, and Rhizobia. It was observed that 37% (100% identity) and 56% (>99% identity) of the isolates matched with the amplified sequence variants (ASVs) from our previous microbiome study. All of these isolates were tested for stress tolerance (high temperature, salinity, acidic pH) and phosphate (P) solubilization along with ammonia (NH₃), indole-3-acetic acid (IAA), 1-aminocyclopropane-1-carboxylate deaminase (ACCD), and siderophore production. The majority (78%) of the isolates were found to be halotolerant, thermotolerant, and acidophilic, and a few of them showed a significant positive response to the production of IAA, NH₃, siderophore, ACCD, and P-solubilization. To evaluate the plant growth promotion (PGP) activity, plant and nodulation assays were performed in the growth chamber conditions for the selected isolates from both the non-rhizobial and rhizobial groups. However, these isolates appeared to be non-nodulating in the tested conditions. Nonetheless, the isolates 2 (Pantoea), 17 (Burkholderia), 21 (Herbaspirillum), 33o (Pseudomonas), and 77 (Rhizobium sp.) showed significant PGP activity in terms of biomass production. Our findings indicate that these isolates have potential for future biotechnological applications through the development of biologicals for sustainable crop improvement. Full article

(This article belongs to the Special Issue Plant Growth-Promoting Bacteria and Plant-Soil Interactions in Harsh Environments)

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15 pages, 5645 KiB

Open AccessArticle

Phosphate-Solubilizing Bacteria with Low-Solubility Fertilizer Improve Soil P Availability and Yield of Kikuyu Grass

by Daniel Torres-Cuesta, Duber Mora-Motta, Juan P. Chavarro-Bermeo, Andres Olaya-Montes, Cesar Vargas-Garcia, Ruth Bonilla and German Estrada-Bonilla

Microorganisms 2023, 11(7), 1748; https://doi.org/10.3390/microorganisms11071748 - 04 Jul 2023

Cited by 1 | Viewed by 2331

Abstract

Inoculation with phosphate-solubilizing bacteria (PSB) and the application of phosphorus (P) sources can improve soil P availability, enhancing the sustainability and efficiency of agricultural systems. The implementation of this technology in perennial grasses, such as Kikuyu grass, for cattle feed in soils with [...] Read more.

Inoculation with phosphate-solubilizing bacteria (PSB) and the application of phosphorus (P) sources can improve soil P availability, enhancing the sustainability and efficiency of agricultural systems. The implementation of this technology in perennial grasses, such as Kikuyu grass, for cattle feed in soils with high P retention, such as Andisols, has been little explored. The objective of this study was to evaluate the productive response of Kikuyu grass and soil P dynamics to BSF inoculation with different P sources. The experiment was conducted on a Kikuyu pasture, which was evaluated for 18 months (September 2020 to March 2022). Three P fertilizers with different solubility levels were applied: diammonium phosphate (DAP) (high-solubility), rock phosphate (RP), and compost (OM) (low-solubility). Moreover, the inoculation of a PSB consortium (Azospirillum brasilense D7, Rhizobium leguminosarum T88 and Herbaspirillum sp. AP21) was tested. Inoculation with PSB and fertilization with rock phosphate (RP) increased soil labile P and acid phosphomonoesterase activity. Increased grass yield and quality were related with higher soil inorganic P (Pi) availability. This study validated, under field conditions, the benefits of PSB inoculation for soil P availability and Kikuyu grass productivity. Full article

(This article belongs to the Special Issue Plant Growth-Promoting Bacteria and Plant-Soil Interactions in Harsh Environments)

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21 pages, 1430 KiB

Open AccessArticle

Endophytes and Plant Extracts as Potential Antimicrobial Agents against Candidatus Liberibacter Asiaticus, Causal Agent of Huanglongbing

by Jessica Dominguez, Krishnaswamy Jayachandran, Ed Stover, Joseph Krystel and Kateel G. Shetty

Microorganisms 2023, 11(6), 1529; https://doi.org/10.3390/microorganisms11061529 - 08 Jun 2023

Cited by 3 | Viewed by 1921

Abstract

Huanglongbing (HLB), also known as citrus greening, is an insidious disease in citrus and has become a threat to the sustainability of the citrus industry worldwide. In the U.S., Candidatus Liberibacter asiaticus (CLas) is the pathogen that is associated with HLB, [...] Read more.

Huanglongbing (HLB), also known as citrus greening, is an insidious disease in citrus and has become a threat to the sustainability of the citrus industry worldwide. In the U.S., Candidatus Liberibacter asiaticus (CLas) is the pathogen that is associated with HLB, an unculturable, phloem-limited bacteria, vectored by the Asian Citrus Psyllid (ACP, Diaphorina citri). There is no known cure nor treatment to effectively control HLB, and current control methods are primarily based on the use of insecticides and antibiotics, where effectiveness is limited and may have negative impacts on beneficial and non-target organisms. Thus, there is an urgent need for the development of effective and sustainable treatment options to reduce or eliminate CLas from infected trees. In the present study, we screened citrus-derived endophytes, their cell-free culture supernatants (CFCS), and crude plant extracts for antimicrobial activity against two culturable surrogates of CLas, Sinorhizobium meliloti and Liberibacter crescens. Candidates considered high-potential antimicrobial agents were assessed directly against CLas in vitro, using a propidium monoazide–based assay. As compared to the negative controls, statistically significant reductions of viable CLas cells were observed for each of the five bacterial CFCS. Subsequent 16S rRNA gene sequencing revealed that each of the five bacterial isolates were most closely related to Bacillus amyloliquefaciens, a species dominating the market of biological control products. As such, the aboveground endosphere of asymptomatic survivor citrus trees, grown in an organic orchard, were found to host bacterial endophytes capable of effectively disrupting CLas cell membranes. These results concur with the theory that native members of the citrus microbiome play a role in the development of HLB. Here, we identify five strains of Bacillus amyloliquefaciens demonstrating notable potential to be used as sources of novel antimicrobials for the sustainable management of HLB. Full article

(This article belongs to the Special Issue Plant Growth-Promoting Bacteria and Plant-Soil Interactions in Harsh Environments)

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18 pages, 2011 KiB

Open AccessArticle

Epigenetic Induction of Secondary Metabolites Production in Endophytic Fungi Penicillium chrysogenum and GC-MS Analysis of Crude Metabolites with Anti-HIV-1 Activity

by John P. Makhwitine, Hezekiel M. Kumalo, Sizwe I. Ndlovu and Nompumelelo P. Mkhwanazi

Microorganisms 2023, 11(6), 1404; https://doi.org/10.3390/microorganisms11061404 - 26 May 2023

Cited by 5 | Viewed by 2127

Abstract

The continuous burden of human immunodeficiency virus-1 in Sub-Saharan Africa, coupled with the inability of antiretroviral agents to eradicate HIV-1 from viral reservoirs, the potential risks of drug resistance development, and the development of adverse effects, emphasizes the need to develop a new [...] Read more.

The continuous burden of human immunodeficiency virus-1 in Sub-Saharan Africa, coupled with the inability of antiretroviral agents to eradicate HIV-1 from viral reservoirs, the potential risks of drug resistance development, and the development of adverse effects, emphasizes the need to develop a new class of HIV-1 inhibitors. Here, we cultivated four endophytic fungal isolates from a medicinal plant, Albizia adianthifolia with the addition of small epigenetic modifiers, sodium butyrate, and valproic acid, to induce the expression of biosynthetic gene clusters encoding active secondary metabolites with probable anti-HIV activities. We identified a non-toxic crude extract of the endophytic fungus Penicillium chrysogenum treated with sodium butyrate to possess significantly greater anti-HIV activity than the untreated extracts. Penicillium chrysogenum P03MB2 showed anti-HIV activity with an IC₅₀ of 0.6024 µg/mL compared to untreated fungal crude extract (IC₅₀ 5.053 µg/mL) when treated with sodium butyrate. The profile of secondary metabolite compounds from the bioactive, partially purified extracts were identified by gas chromatography-mass spectrometry (GC-MS), and more bioactive compounds were detected in treated P. chrysogenum P03MB2 fractions than in untreated fractions. Pyrrolo[1,2-a]pyrazine-1,4-dione, hexahydro (13.64%), cyclotrisiloxane, hexamethyl (8.18%), cyclotetrasiloxane, octamethyl (7.23%), cyclopentasiloxane, decamethyl (6.36%), quinoline, 1,2-dihydro-2,24-trimethyl (5.45%), propanenitrile (4.55%), deca-6,9-diene (4.55%), dibutyl phthalate (4.55%), and silane[1,1-dimethyl-2-propenyl)oxy]dimethyl (2.73%) were the most abundant compounds. These results indicate that treatment of endophytic fungi with small epigenetic modifiers enhances the secretion of secondary metabolites with stronger anti-HIV-1 properties, acknowledging the feasibility of epigenetic modification as an innovative approach for the discovery of cryptic fungal metabolites which can be developed into therapeutic compounds. Full article

(This article belongs to the Special Issue Plant Growth-Promoting Bacteria and Plant-Soil Interactions in Harsh Environments)

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15 pages, 3645 KiB

Open AccessArticle

Impact of Water Shortage on Soil and Plant Attributes in the Presence of Arbuscular Mycorrhizal Fungi from a Harsh Environment

by Antonio Marcos Miranda Silva, Henrique Petry Feiler, Xue Qi, Victor Lucas Vieira Prudêncio de Araújo, Gileno Vieira Lacerda-Júnior, Paulo Ivan Fernandes-Júnior and Elke Jurandy Bran Nogueira Cardoso

Microorganisms 2023, 11(5), 1144; https://doi.org/10.3390/microorganisms11051144 - 28 Apr 2023

Cited by 2 | Viewed by 1249

Abstract

Arbuscular mycorrhizal fungi (AMF) play a crucial role in plant health due to their ability to improve tolerance to biotic and abiotic stresses. Our aim was to evaluate the effectiveness of a pool of native AMF from a harsh environment on plant performance [...] Read more.

Arbuscular mycorrhizal fungi (AMF) play a crucial role in plant health due to their ability to improve tolerance to biotic and abiotic stresses. Our aim was to evaluate the effectiveness of a pool of native AMF from a harsh environment on plant performance and changes in soil attributes under different levels of drought. An experiment using maize was established, varying the soil water content to simulate severe drought (30% of the water-holding capacity [WHC]), moderate (50% of the WHC) and no drought (80% of the WHC, control treatment). Soil and plant attributes were measured (enzyme activity, microbial biomass, AMF root colonisation and plant biomass and nutrient uptake). There was a two-fold increase in plant biomass under moderate drought when compared to no drought treatment, but there was no difference in nutrient uptake. Under severe drought, there were the highest enzyme activities related to phosphorus (P) cycling and P microbial biomass, indicating higher P microbial immobilization. The increase in AMF root colonisation was observed in plants under moderate and no drought. Our findings demonstrated that the better use of the AMF inoculum varied according to drought levels, with better performance under moderate drought due to the increase in plant biomass. Full article

(This article belongs to the Special Issue Plant Growth-Promoting Bacteria and Plant-Soil Interactions in Harsh Environments)

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14 pages, 2040 KiB

Open AccessArticle

Inoculation with Plant Growth-Promoting Bacteria and Nitrogen Doses Improves Wheat Productivity and Nitrogen Use Efficiency

by Rafaela Neris Gaspareto, Arshad Jalal, William Cesar Nishimoto Ito, Carlos Eduardo da Silva Oliveira, Cássia Maria de Paula Garcia, Eduardo Henrique Marcandalli Boleta, Poliana Aparecida Leonel Rosa, Fernando Shintate Galindo, Salatiér Buzetti, Bhim Bahadur Ghaley and Marcelo Carvalho Minhoto Teixeira Filho

Microorganisms 2023, 11(4), 1046; https://doi.org/10.3390/microorganisms11041046 - 17 Apr 2023

Cited by 2 | Viewed by 1923

Abstract

Wheat is one of the staple foods of the global population due to its adaptability to a wide range of environments. Nitrogen is one of the crucial limiting factors in wheat production and is considered a challenge to food security. Therefore, sustainable agricultural [...] Read more.

Wheat is one of the staple foods of the global population due to its adaptability to a wide range of environments. Nitrogen is one of the crucial limiting factors in wheat production and is considered a challenge to food security. Therefore, sustainable agricultural technologies such as seed inoculation with plant growth-promoting bacteria (PGPBs) can be adopted to promote biological nitrogen fixation (BNF) for higher crop productivity. In this context, the objective of the current study was to evaluate the effects of nitrogen fertilization and seed inoculations with Azospirillum brasilense, Bacillus subtilis and A. brasilense + B. subtilis on agronomic and yield attributes, grain yield, grain N accumulation, N use efficiency and applied N recovery in Brazilian Cerrado, which consists of gramineous woody savanna. The experiment was carried out in two cropping seasons in Rhodic Haplustox soil under a no-tillage system. The experiment was designed in a randomized complete block in a 4 × 5 factorial scheme, with four replications. The treatments consisted of four seed inoculations (control—without inoculation, inoculation with A. brasilense, B. subtilis and A. brasilense + B. subtilis) under five N doses (0, 40, 80, 120 and 160 kg ha⁻¹, applied from urea) at the wheat tillering stage. Seed co-inoculation with A. brasilense + B. subtilis increased grain N accumulation, number of spikes m⁻¹, grains spike⁻¹ and grain yield of wheat in an irrigated no-tillage system of tropical savannah, regardless of the applied N doses. Nitrogen fertilization at a dose of 80 kg ha⁻¹ significantly increased grain N accumulation and number of grains spikes⁻¹ and nitrogen use efficiency. Recovery of applied N was increased with inoculation of B. subtilis and co-inoculation of A. brasilense + B. subtilis at increasing N doses. Therefore, N fertilization can be reduced by the inclusion of co-inoculation with A. brasilense + B. subtilis in the cultivation of winter wheat under a no-tillage system of Brazilian Cerrado. Full article

(This article belongs to the Special Issue Plant Growth-Promoting Bacteria and Plant-Soil Interactions in Harsh Environments)

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18 pages, 5067 KiB

Open AccessArticle

Changing Rhizosphere Microbial Community and Metabolites with Developmental Stages of Coleus barbatus

by Vijay Lakshmi Jamwal, Irshad Ahmad Rather, Sajad Ahmed, Amit Kumar and Sumit G. Gandhi

Microorganisms 2023, 11(3), 705; https://doi.org/10.3390/microorganisms11030705 - 09 Mar 2023

Viewed by 1324

Abstract

Coleus barbatus is a medicinal herb belonging to Lamiaceae. It is the only living organism known to produce forskolin, which is a labdane diterpene and is reported to activate adenylate cyclase. Microbes associated with plants play an important role in maintaining plant health. [...] Read more.

Coleus barbatus is a medicinal herb belonging to Lamiaceae. It is the only living organism known to produce forskolin, which is a labdane diterpene and is reported to activate adenylate cyclase. Microbes associated with plants play an important role in maintaining plant health. Recently, the targeted application of beneficial plant-associated microbes and their combinations in abiotic and biotic stress tolerance has gained momentum. In this work, we carried out the rhizosphere metagenome sequencing of C. barbatus at different developmental stages to understand how rhizosphere microflora are affected by and affect the metabolite content in plants. We found that the Kaistobacter genus was abundantly present in the rhizosphere of C. barbatus and its accumulation pattern appears to correlate with the quantities of forskolin in the roots at different developmental stages. Members of the Phoma genus, known for several pathogenic species, were in lower numbers in the C. barbatus rhizosphere in comparison with C. blumei. To our knowledge, this is the first metagenomic study of the rhizospheric microbiome of C. barbatus, which may help to explore and exploit the culturable and non-culturable microbial diversity present in the rhizosphere. Full article

(This article belongs to the Special Issue Plant Growth-Promoting Bacteria and Plant-Soil Interactions in Harsh Environments)

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13 pages, 3260 KiB

Open AccessArticle

Comprehensive Genomics and Proteomics Analysis Reveals the Multiple Response Strategies of Endophytic Bacillus sp. WR13 to Iron Limitation

by Zonghao Yue, Yongchuang Liu, Yanjuan Chen, Can Chen, Ju Zhang, Le He and Keshi Ma

Microorganisms 2023, 11(2), 367; https://doi.org/10.3390/microorganisms11020367 - 01 Feb 2023

Cited by 2 | Viewed by 1344

Abstract

Iron (Fe) is an important metal element for the growth of bacteria. Many bacteria respond to Fe limitation through a variety of strategies. We previously isolated an endophyte Bacillus sp. WR13 from wheat root. However, whether and how this strain can cope with [...] Read more.

Iron (Fe) is an important metal element for the growth of bacteria. Many bacteria respond to Fe limitation through a variety of strategies. We previously isolated an endophyte Bacillus sp. WR13 from wheat root. However, whether and how this strain can cope with Fe-deficient environments remains unclear. In this study, the growth of WR13 under Fe starvation was investigated, and the underlying mechanisms of WR13 in response to Fe starvation were elucidated via genomics and iTRAQ-based proteomics. Under Fe limitation, WR13 showed a growth pattern similar to that of Fe sufficiency. Genomics analysis demonstrated that WR13 had gene clusters related to siderophore synthesis (dhbACEBF), transportation (bcbE), uptake (feuABC-yusV) and hydrolysis (besA). These genes were significantly up-regulated in Fe-starved WR13, which resulted in more siderophore production. Proteomics data revealed that many Fe-containing proteins such as ACO, HemQ, ferredoxin, CNP, and SufD were significantly reduced under Fe limitation. Meanwhile, significant decreases in many proteins involved in glycolysis, TCA cycle, pentose phosphate pathway; asparagine, glutamine, methionine, and serine metabolism; and phospholipid hydrolysis were also observed. Overall, this study shows that Bacillus sp. WR13 was able to respond to Fe limitation via multiple strategies and provides a theoretical basis for the application of WR13 in Fe-deficient soil. Full article

(This article belongs to the Special Issue Plant Growth-Promoting Bacteria and Plant-Soil Interactions in Harsh Environments)

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23 pages, 7930 KiB

Open AccessArticle

Calendula officinalis—A Great Source of Plant Growth Promoting Endophytic Bacteria (PGPEB) and Biological Control Agents (BCA)

by Polina C. Tsalgatidou, Eirini-Evangelia Thomloudi, Kallimachos Nifakos, Costas Delis, Anastasia Venieraki and Panagiotis Katinakis

Microorganisms 2023, 11(1), 206; https://doi.org/10.3390/microorganisms11010206 - 13 Jan 2023

Cited by 7 | Viewed by 3353

Abstract

The application of beneficial bacteria may present an alternative approach to chemical plant protection and fertilization products as they enhance growth and resistance to biotic and abiotic stresses. Plant growth-promoting bacteria are found in the rhizosphere, epiphytically or endophytically (Plant Growth Promoting Endophytic [...] Read more.

The application of beneficial bacteria may present an alternative approach to chemical plant protection and fertilization products as they enhance growth and resistance to biotic and abiotic stresses. Plant growth-promoting bacteria are found in the rhizosphere, epiphytically or endophytically (Plant Growth Promoting Endophytic Bacteria, PGPEB). In the present study, 36 out of 119 isolated endophytic bacterial strains from roots, leaves and flowers of the pharmaceutical plant Calendula officinalis were further identified and classified into Bacillus, Pseudomonas, Pantoea, Stenotrophomonas and Rhizobium genera. Selected endophytes were evaluated depending on positive reaction to different plant growth promoting (PGP) traits, motility, survival rate and inhibition of phytopathogenic fungi in vitro and ex vivo (tomato fruit). Bacteria were further assessed for their plant growth effect on Arabidopsis thaliana seedlings and on seed bio-primed tomato plantlets, in vitro. Our results indicated that many bacterial endophytes increased seed germination, promoted plant growth and changed root structure by increasing lateral root density and length and root hair formation. The most promising antagonistic PGPEB strains (Cal.r.29, Cal.l.30, Cal.f.4, Cal.l.11, Cal.f.2.1, Cal.r.19 and Cal.r.11) are indicated as effective biological control agents (BCA) against Botrytis cinerea on detached tomato fruits. Results underlie the utility of beneficial endophytic bacteria for sustainable and efficient crop production and disease control. Full article

(This article belongs to the Special Issue Plant Growth-Promoting Bacteria and Plant-Soil Interactions in Harsh Environments)

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Review

Jump to: Research, Other

26 pages, 475 KiB

Open AccessReview

Developments and Prospects of Farmland Application of Biogas Slurry in China—A Review

by Zichen Wang, Isaac A. Sanusi, Jidong Wang, Xiaomei Ye, Evariste B. Gueguim Kana, Ademola O. Olaniran and Hongbo Shao

Microorganisms 2023, 11(11), 2675; https://doi.org/10.3390/microorganisms11112675 - 31 Oct 2023

Cited by 4 | Viewed by 1519

Abstract

Biogas slurry (BS) is an attractive agricultural waste resource which can be used to regulate soil microbial communities, enhance nutrient absorption capacity of crops, promote plant–soil interactions, and consequently, increase crop productivity. Presently, BS discharge is not environmentally friendly. It is therefore necessary [...] Read more.

Biogas slurry (BS) is an attractive agricultural waste resource which can be used to regulate soil microbial communities, enhance nutrient absorption capacity of crops, promote plant–soil interactions, and consequently, increase crop productivity. Presently, BS discharge is not environmentally friendly. It is therefore necessary to explore alternative efficient utilization of BS. The use of BS as fertilizer meets the requirements for sustainable and eco-friendly development in agriculture, but this has not been fully actualized. Hence, this paper reviewed the advantages of using BS in farmland as soil fertilization for the improvement of crop production and quality. This review also highlighted the potential of BS for the prevention and control of soil acidification, salinization, as well as improve microbial structure and soil enzyme activity. Moreover, this review reports on the current techniques, application methods, relevant engineering measures, environmental benefits, challenges, and prospects associated with BS utilization. Lastly, additional research efforts require for optimal utilization of BS in farmlands were elucidated. Full article

(This article belongs to the Special Issue Plant Growth-Promoting Bacteria and Plant-Soil Interactions in Harsh Environments)

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10 pages, 289 KiB

Open AccessReview

Microbials for Agriculture: Why Do They Call Them Biostimulants When They Mean Probiotics?

by Juan Sanjuán, Maria Caridad Nápoles, Daniel Pérez-Mendoza, María J. Lorite and Dulce N. Rodríguez-Navarro

Microorganisms 2023, 11(1), 153; https://doi.org/10.3390/microorganisms11010153 - 06 Jan 2023

Cited by 5 | Viewed by 2401

Abstract

There is growing interest in using plant-beneficial microorganisms to partially replace chemicals and help reduce the environmental impact of agriculture. Formulated microbial products or inoculants for agriculture contain single strains or a consortium of live microbes, well characterized and biosafe, which can contribute [...] Read more.

There is growing interest in using plant-beneficial microorganisms to partially replace chemicals and help reduce the environmental impact of agriculture. Formulated microbial products or inoculants for agriculture contain single strains or a consortium of live microbes, well characterized and biosafe, which can contribute to the growth, health, and development of a plant host. This concept conforms to the definition of probiotics. However, some plant-growth-promoting microorganisms (PGPMs) have been considered a category of biostimulants since some years ago, despite the traditional concept of biostimulants involves substances or materials with no fertilizer value, which in minute amounts promote plant growth. The inclusion of PGPMs together with substances has also involved a significant distortion of the classical concept of biostimulants. Regulations such as the recent EU Fertilizing Products Regulation (EU No. 2019/1009) have incorporated the new definition of biostimulants and included microbials as a subcategory of biostimulants. We discuss that this regulation and the forthcoming European harmonized standards disregard some key features of microbial products, such as the live, true biological nature of their active principles. The factors that determine the complex functional compatibility of plant–microbe associations, and important biosafety issues that concern the intentional release of microbes into the environment, seem to be also ignored. We anticipate that by equating microbials to chemicals, the biological nature of microbial products and their specific requirements will be underestimated, with pernicious consequences for their future development and success. Full article

(This article belongs to the Special Issue Plant Growth-Promoting Bacteria and Plant-Soil Interactions in Harsh Environments)

Other

Jump to: Research, Review

12 pages, 1481 KiB

Open AccessPerspective

The Role of the Plant–Soil Relationship in Agricultural Production—With Particular Regard to PGPB Application and Phytoremediation

by Szilvia Kisvarga, Dóra Hamar-Farkas, Máté Ördögh, Katalin Horotán, András Neményi, Dezső Kovács and László Orlóci

Microorganisms 2023, 11(6), 1616; https://doi.org/10.3390/microorganisms11061616 - 19 Jun 2023

Cited by 5 | Viewed by 1933

Abstract

Plant growth-promoting bacteria (PGPB) and other living organisms can help with the challenges of modern agriculture. PGPB offer ever-expanding possibilities for science and commerce, and the scientific results have been very advanced in recent years. In our current work, we collected the scientific [...] Read more.

Plant growth-promoting bacteria (PGPB) and other living organisms can help with the challenges of modern agriculture. PGPB offer ever-expanding possibilities for science and commerce, and the scientific results have been very advanced in recent years. In our current work, we collected the scientific results of recent years and the opinions of experts on the subject. Opinions and results on soil–plant relations, as well as the importance of PGPB and the latest related experiences, are important topics of our review work, which highlights the scientific results of the last 3–4 years. Overall, it can be concluded from all these observations that the bacteria that promote plant development are becoming more and more important in agriculture almost all over the world, thus, promoting more sustainable and environmentally conscious agricultural production and avoiding the use of artificial fertilizers and chemicals. Since many mechanisms of action, namely biochemical and operational processes, are still under investigation, a new emerging scientific direction is expected in the coming years with regard to PGPB, microbial, and other plant growth-stimulating substances, in which omics and microbial modulation also play a leading role. Full article

(This article belongs to the Special Issue Plant Growth-Promoting Bacteria and Plant-Soil Interactions in Harsh Environments)

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