A Survey of Methylobacterium Species and Strains Reveals Widespread Production and Varying Profiles of Cytokinin Phytohormones

Liquid Chromatography Tandem Mass ◽

Plant Growth Promoting ◽

Growth Promoting ◽

Selection For ◽

Abstract BackgroundSymbiotic Methylobacterium strains comprise a significant part of plant microbiomes. Their presence enhances plant productivity and stress resistance, prompting classification of these strains as plant growth-promoting bacteria (PGPB). Methylobacteria can synthesize unusually high levels of plant hormones, called cytokinins (CKs), including the most active form, trans-Zeatin (tZ). ResultsThis study provides a comprehensive inventory of 46 representatives of Methylobacterium genus with respect to phytohormone production in vitro, including 16 CK forms, abscisic acid (ABA) and indole-3-acetic acid (IAA). High performance-liquid chromatography - tandem mass spectrometry (HPLC-MS/MS) analyses revealed varying abilities of Methylobacterium strains to secrete phytohormones that ranged from 5.09 to 191.47 pmol mL-1 for total CKs, and 0.46 to 82.16 pmol mL-1 for tZ. Results indicate that reduced methanol availability, the sole carbon source for bacteria in the medium, stimulates CK secretion by Methylobacterium. Additionally, select strains were able to transform L-tryptophan into IAA while no ABA production was detected.ConclusionsTo better understand features of CKs in plants, this study uncovers CK profiles of Methylobacterium that are instrumental in microbe selection for effective biofertilizer formulations.

Compatibility of Azospirillum brasilense with Pesticides Used for Treatment of Maize Seeds

International Journal of Microbiology ◽

10.1155/2020/8833879 ◽

2020 ◽

Vol 2020 ◽

pp. 1-8

Author(s):

Mariana S. Santos ◽

Artur B. L. Rondina ◽

Marco A. Nogueira ◽

Mariangela Hungria

Keyword(s):

Plant Growth ◽

Root Hair ◽

Azospirillum Brasilense ◽

Plant Protection ◽

Root Volume ◽

Maize Seeds ◽

Plant Growth Promoting ◽

Seed treatment with chemical pesticides is commonly used as an initial plant protection procedure against pests and diseases. However, the use of such chemicals may impair the survival and performance of beneficial microorganisms introduced via inoculants, such as the plant growth-promoting bacterium Azospirillum brasilense. We assessed the compatibility between the most common pesticide used in Brazil for the treatment of maize seeds, composed of two fungicides, and one insecticide, with the commercial strains Ab-V5 and Ab-V6 of A. brasilense, and evaluated the impacts on initial plant development. The toxicity of the pesticide to A. brasilense was confirmed, with an increase in cell mortality after only 24 hours of exposure in vitro. Seed germination and seedling growth were not affected neither by the A. brasilense nor by the pesticide. However, under greenhouse conditions, the pesticide affected root volume and dry weight and root-hair incidence, but the toxicity was alleviated by the inoculation with A. brasilense for the root volume and root-hair incidence parameters. In maize seeds inoculated with A. brasilense, the pesticide negatively affected the number of branches, root-hair incidence, and root-hair length. Therefore, new inoculant formulations with cell protectors and the development of compatible pesticides should be searched to guarantee the benefits of inoculation with plant growth-promoting bacteria.

Participation of abscisic acid and gibberellins produced by endophytic Azospirillum in the alleviation of drought effects in maize

Botany ◽

10.1139/b09-023 ◽

2009 ◽

Vol 87 (5) ◽

pp. 455-462 ◽

Cited By ~ 159

Author(s):

Ana C. Cohen ◽

Claudia N. Travaglia ◽

Rubén Bottini ◽

Patricia N. Piccoli

Keyword(s):

Abscisic Acid ◽

Water Stress ◽

Zea Mays L ◽

Azospirillum Lipoferum ◽

Stress Alleviation ◽

Relative Water ◽

Plant Growth Promoting ◽

Growth Promoting ◽

Azospirillum spp. are plant growth promoting bacteria (PGPB) that enhance growth by several mechanisms, including the production of phytohormones such as abscisic acid (ABA), indole-3-acetic acid (IAA), and gibberellins (GAs). Their presence may also alleviate plant water stress. In the present paper, the effects of Azospirillum lipoferum in maize ( Zea mays L.) plants treated with inhibitors of ABA and GA synthesis, fluridone (F) and prohexadione-Ca (P), respectively, and either submitted to drought stress or provided sufficient water, were analysed. Fluridone diminished the growth of plants that had been well watered, in a manner similar to drought, but inoculation with Azospirillum completely reversed this effect. The relative water content of the F-treated and drought-stressed plants was significantly lower (even though drought-stressed plants had been allowed to recover for one week), and this effect was completely neutralized by Azospirillum. These results were correlated with ABA levels assessed by GC-EIMS. Growth was diminished in drought-submitted plants treated with P, alone or combined with F, even though ABA levels were enhanced, suggesting that GAs produced by the bacterium are also important in stress alleviation. The results suggest that both ABA and GAs contribute to water-stress alleviation of plants by Azospirillum.

Acclimatization of Pouteria gardeneriana Radlk micropropagated plantlets: role of in vitro rooting and plant growth–promoting bacteria

Current Plant Biology ◽

10.1016/j.cpb.2021.100209 ◽

2021 ◽

pp. 100209

Author(s):

Mariluza Silva Leite ◽

Tainara Eler Furtado Pinto ◽

Agda Rabelo Centofante ◽

Aurélio Rubio Neto ◽

Fabiano Guimarães Silva ◽

...

Keyword(s):

Plant Growth ◽

In Vitro Rooting ◽

Plant Growth Promoting ◽

Plant Growth-Promoting Bacteria as an Emerging Tool to Manage Bacterial Rice Pathogens

Microorganisms ◽

10.3390/microorganisms9040682 ◽

2021 ◽

Vol 9 (4) ◽

pp. 682

Author(s):

Mohamad Syazwan Ngalimat ◽

Erneeza Mohd Hata ◽

Dzarifah Zulperi ◽

Siti Izera Ismail ◽

Mohd Razi Ismail ◽

...

Keyword(s):

Plant Growth ◽

Large Scale ◽

Promising Alternative ◽

Rice Plants ◽

Plant Growth Promoting ◽

Growth Promoting ◽

Rice Pathogens ◽

Grain Losses

As a major food crop, rice (Oryza sativa) is produced and consumed by nearly 90% of the population in Asia with less than 9% produced outside Asia. Hence, reports on large scale grain losses were alarming and resulted in a heightened awareness on the importance of rice plants’ health and increased interest against phytopathogens in rice. To serve this interest, this review will provide a summary on bacterial rice pathogens, which can potentially be controlled by plant growth-promoting bacteria (PGPB). Additionally, this review highlights PGPB-mediated functional traits, including biocontrol of bacterial rice pathogens and enhancement of rice plant’s growth. Currently, a plethora of recent studies address the use of PGPB to combat bacterial rice pathogens in an attempt to replace existing methods of chemical fertilizers and pesticides that often lead to environmental pollutions. As a tool to combat bacterial rice pathogens, PGPB presented itself as a promising alternative in improving rice plants’ health and simultaneously controlling bacterial rice pathogens in vitro and in the field/greenhouse studies. PGPB, such as Bacillus, Pseudomonas, Enterobacter, Streptomyces, are now very well-known. Applications of PGPB as bioformulations are found to be effective in improving rice productivity and provide an eco-friendly alternative to agroecosystems.

Evaluation of Antifusarium and Auxin Production of Trichoderma virens InaCC F1030 Isolated from Rhizosphere of Banana

Journal of Microbial Systematics and Biotechnology ◽

10.37604/jmsb.v2i1.39 ◽

2020 ◽

Vol 2 (1) ◽

pp. 31-39

Author(s):

Toga Pangihotan Napitupulu

Keyword(s):

Culture Collection ◽

Trichoderma Virens ◽

Plant Host ◽

Trichoderma Species ◽

Auxin Production ◽

Volatile Organic ◽

Plant Growth Promoting ◽

Growth Promoting ◽

Banana rhizosphere harbors a unique diversity of microbes including fungi that play critical roles in the growth of the plant host as well as might be important for biologically controlling the fungal soil-borne pathogens particularly Fusarium oxysporum f.sp. cubense (Foc), the causing agent of devastating Panama wilt. Among other fungi, we have succeeded to isolate a Trichoderma species from rhizosphere of healthy banana. Molecular identification revealed the isolate as Trichoderma virens InaCC F1030 (being collection of Indonesian Culture Collection or InaCC). Therefore, the aim of this study was to investigate the biological control of our isolate against Foc as well as plant growth promoting ability through its ability to produce auxin (indole-3-acetic acid/IAA). Two approaches were employed to evaluate the antagonism of our isolate against Foc, through direct confrontation test and volatile organic compounds (VOCs) producing. We found that our isolate was considered as antagonistic to the Foc, but not highly antagonistic according to direct confrontation assay. It was also revealed that our isolate produces the VOCs that inhibited around 50% of the mycelial growth of the test pathogen after six to seven days of exposure. Our isolate was able to produce the IAA in axenic submerged fermentation condition particularly in the presence of the precursor L-tryptophan. IAA production ability as well as the mycelial biomass of fungus were increased approximately 17% and 120% respectively as the effect of supplementation of 0.1% of L-tryptophan. These in vitro bioassays lead us to conclude that somehow our isolate T. virens InaCC F1030 has potency to be utilized as biocontrol and biofertilizer agent.

De novo genome assembly of Bacillus altitudinis 19RS3 and Bacillus altitudinis T5S-T4, two plant growth-promoting bacteria isolated from Ilex paraguariensis St. Hil. (yerba mate)

PLoS ONE ◽

10.1371/journal.pone.0248274 ◽

2021 ◽

Vol 16 (3) ◽

pp. e0248274

Author(s):

Iliana Julieta Cortese ◽

María Lorena Castrillo ◽

Andrea Liliana Onetto ◽

Gustavo Ángel Bich ◽

Pedro Darío Zapata ◽

...

Keyword(s):

Plant Growth ◽

De Novo ◽

Draft Genome ◽

Ilex Paraguariensis ◽

De Novo Genome Assembly ◽

Bacillus Altitudinis ◽

Plant Growth Promoting ◽

Plant growth-promoting bacteria (PGPB) are a heterogeneous group of bacteria that can exert beneficial effects on plant growth directly or indirectly by different mechanisms. PGPB-based inoculant formulation has been used to replace chemical fertilizers and pesticides. In our previous studies, two endophytic endospore-forming bacteria identified as Bacillus altitudinis were isolated from roots of Ilex paraguariensis St. Hil. seedlings and selected for their plant growth-promoting (PGP) properties shown in vitro and in vivo. The purposes of this work were to assemble the genomes of B. altitudinis 19RS3 and T5S-T4, using different assemblers available for Windows and Linux and to select the best assembly for each strain. Both genomes were also automatically annotated to detect PGP genes and compare sequences with other genomes reported. Library construction and draft genome sequencing were performed by Macrogen services. Raw reads were filtered using the Trimmomatic tool. Genomes were assembled using SPAdes, ABySS, Velvet, and SOAPdenovo2 assemblers for Linux, and Geneious and CLC Genomics Workbench assemblers for Windows. Assembly evaluation was done by the QUAST tool. The parameters evaluated were the number of contigs ≥ 500 bp and ≥ 1000 bp, the length of the longest contig, and the N50 value. For genome annotation PROKKA, RAST, and KAAS tools were used. The best assembly for both genomes was obtained using Velvet. The B. altitudinis 19RS3 genome was assembled into 15 contigs with an N50 value of 1,943,801 bp. The B. altitudinis T5S-T4 genome was assembled into 24 contigs with an N50 of 344,151 bp. Both genomes comprise several genes related to PGP mechanisms, such as those for nitrogen fixation, iron metabolism, phosphate metabolism, and auxin biosynthesis. The results obtained offer the basis for a better understanding of B. altitudinis 19RS3 and T5S-T4 and make them promissory for bioinoculant development.

In vitro antagonistic potential, plant growth-promoting activity and indole-3-acetic acid producing trait of bacterial isolates from spent mushroom substrate of Agaricus bisporus

Journal of Agricultural and Marine Sciences [JAMS] ◽

10.24200/jams.vol25iss2pp22-29 ◽

2020 ◽

Vol 25 (2) ◽

pp. 22

Author(s):

Rethinasamy Velazhahan ◽

Shima Nasser Hamed Al-Mamari ◽

Abdullah Mohammed Al-Sadi ◽

Issa Hashil Al-Mahmooli ◽

S. P. Sathish Babu

Keyword(s):

Plant Growth ◽

Agaricus Bisporus ◽

Growth Promotion ◽

Inhibition Zone ◽

Bacterial Isolates ◽

Plant Growth Promoting ◽

Antagonistic Potential ◽

Growth Promoting ◽

Spent mushroom substrate (SMS) is widely used as fertilizer and to control plant diseases. The microorganisms surviving in SMS play a crucial role in plant growth promotion and biocontrol properties of SMS. In this study, an effort was made to isolate and characterize the bacterial species present in the SMS of Agaricus bisporus and to study their antagonistic potential, plant growth-promoting ability and indole-3-acetic acid (IAA) producing trait. Six different bacterial isolates exhibiting morphological variabilities were obtained from the SMS by serial dilution technique. On the basis of 16S rRNA gene sequences, these isolates were identified as Staphylococcus epidermidis (Sh1 and Sh3), S. aureus (Sh2), Bacillus albus (Sh4), Delftia lacustris (Sh6) and Comamonas aquatica (Sh7). These bacterial strains were assayed for their antagonism against Pythium aphanidermatum, a phytopathogenic oomycete. The results of in vitro dual culture assay revealed that all the 6 bacterial isolates showed low levels of suppression of P. aphanidermatum and recorded less than 5 mm inhibition zone. Among the bacterial isolates, S. epidermidis Sh3 recorded the maximum inhibition zone of 4.2 mm. Plant growth promotion test using roll paper towel method revealed that C. aquatica Sh7, B. albus Sh4, D. lacustris Sh6 and S. epidermidis Sh3 caused a significant increase in seedling vigour of cucumber compared to control. The seeds treated with the bacterial isolate C. aquatica Sh7 showed the maximum seedling vigor. Assessment of in vitro production of IAA by the bacterial isolates revealed that the bacterial isolates highly varied (ranging from 0.28 to 9.25 mg L-1) in their potential for production of IAA. The maximum amount of IAA was produced by C. aquatica Sh7 (9.25 mg L-1), while the minimum was produced by S. epidermidis Sh1 (0.28 mg L-1).

Characterization of cultivable putative endophytic plant growth promoting bacteria associated with maize cultivars (Zea mays L.) and their inoculation effects in vitro

Applied Soil Ecology ◽

10.1016/j.apsoil.2012.02.009 ◽

2012 ◽

Vol 58 ◽

pp. 21-28 ◽

Cited By ~ 80

Author(s):

Adriana Montañez ◽

Andrea Rodríguez Blanco ◽

Claudia Barlocco ◽

Martin Beracochea ◽

Margarita Sicardi

Keyword(s):

Zea Mays ◽

Plant Growth ◽

Zea Mays L ◽

Maize Cultivars ◽

Plant Growth Promoting ◽

Genome-guided insights of tropical Bacillus strains efficient in maize growth promotion

FEMS Microbiology Ecology ◽

10.1093/femsec/fiaa157 ◽

2020 ◽

Vol 96 (9) ◽

Author(s):

Camila Cristina Vieira Velloso ◽

Christiane Abreu de Oliveira ◽

Eliane Aparecida Gomes ◽

Ubiraci Gomes de Paula Lana ◽

Chainheny Gomes de Carvalho ◽

...

Keyword(s):

Plant Growth ◽

Growth Promotion ◽

Dry Weight ◽

Phenotypic Characterization ◽

Maize Genotypes ◽

Plant Growth Promoting ◽

Growth Promoting ◽

Bacillus Strains

ABSTRACT Plant growth promoting bacteria (PGPB) are an efficient and sustainable alternative to mitigate biotic and abiotic stresses in maize. This work aimed to sequence the genome of two Bacillus strains (B116 and B119) and to evaluate their plant growth-promoting (PGP) potential in vitro and their capacity to trigger specific responses in different maize genotypes. Analysis of the genomic sequences revealed the presence of genes related to PGP activities. Both strains were able to produce biofilm and exopolysaccharides, and solubilize phosphate. The strain B119 produced higher amounts of IAA-like molecules and phytase, whereas B116 was capable to produce more acid phosphatase. Maize seedlings inoculated with either strains were submitted to polyethylene glycol-induced osmotic stress and showed an increase of thicker roots, which resulted in a higher root dry weight. The inoculation also increased the total dry weight and modified the root morphology of 16 out of 21 maize genotypes, indicating that the bacteria triggered specific responses depending on plant genotype background. Maize root remodeling was related to growth promotion mechanisms found in genomic prediction and confirmed by in vitro analysis. Overall, the genomic and phenotypic characterization brought new insights to the mechanisms of PGP in tropical Bacillus.

Auxin-producing Bacillus sp.: Auxin quantification and effect on the growth of Solanum tuberosum

Pure and Applied Chemistry ◽

10.1351/pac-con-09-02-06 ◽

2010 ◽

Vol 82 (1) ◽

pp. 313-319 ◽

Cited By ~ 37

Author(s):

Ambreen Ahmed ◽

Shahida Hasnain

Keyword(s):

Solanum Tuberosum ◽

Plant Growth ◽

High Performance ◽

Growth Parameters ◽

Chromatography Analysis ◽

Auxin Production ◽

Plant Growth Promoting ◽

Tryptophan Concentration ◽

Plant-associated bacteria are known to improve plant growth and play a major role in the development of plants. The present study is concerned with the isolation of two auxin-producing plant growth-promoting bacteria (PGPB). On the basis of 16S rRNA sequencing, both of the strains are identified as Bacillus sp. Maximum auxin production was observed at 37 °C after 48 h of incubation. Increase in tryptophan concentration stimulated auxin production by the isolates. High-performance liquid chromatography analysis showed that the bacterial auxin exhibited similar retention time as the standard indole-3-acetic acid (IAA). Sprouts of Solanum tuberosum var. Desiree were inoculated with the isolates. Comparison of various growth parameters of inoculated plants with non-inoculated plants revealed the improvement of plant growth by bacterial inoculation. Almost 40 and 35 % increase in shoot length with P4 and S6 inoculation, respectively, was observed. Considerable improvement in root growth was observed with an increase in the number and length of roots. On the basis of the above findings, it is concluded that the plant growth-promoting Bacillus strains affect S. tuberosum beneficially, resulting in improved plant growth.