Root Morphogenesis of Arabidopsis thaliana Tuned by Plant Growth-Promoting Streptomyces Isolated From Root-Associated Soil of Artemisia annua

In this study, the capacity to tune root morphogenesis by a plant growth-promoting rhizobacterium, Streptomyces lincolnensis L4, was investigated from various aspects including microbial physiology, root development, and root endophytic microbial community. Strain L4 was isolated from the root-associated soil of 7-year plantation of Artemisia annua. Aiming at revealing the promotion mechanism of Streptomyces on root growth and development, this study first evaluated the growth promotion characters of S. lincolnensis L4, followed by investigation in the effect of L4 inoculation on root morphology, endophytic microbiota of root system, and expression of genes involved in root development in Arabidopsis thaliana. Streptomyces lincolnensis L4 is able to hydrolyze organic and inorganic phosphorus, fix nitrogen, and produce IAA, ACC deaminase, and siderophore, which shaped specific structure of endophytic bacterial community with dominant Streptomyces in roots and promoted the development of roots. From the observation of root development characteristics, root length, root diameter, and the number of root hairs were increased by inoculation of strain L4, which were verified by the differential expression of root development-related genes in A. thaliana. Genomic traits of S. lincolnensis L4 which further revealed its capacity for plant growth promotion in which genes involved in phosphorus solubilization, ACC deamination, iron transportation, and IAA production were identified. This root growth-promoting strain has the potential to develop green method for regulating plant development. These findings provide us ecological knowledge of microenvironment around root system and a new approach for regulating root development.

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Plantibacter flavus, Curtobacterium herbarum, Paenibacillus taichungensis, and Rhizobium selenitireducens Endophytes Provide Host-Specific Growth Promotion of Arabidopsis thaliana, Basil, Lettuce, and Bok Choy Plants

Applied and Environmental Microbiology ◽

10.1128/aem.00383-19 ◽

2019 ◽

Vol 85 (19) ◽

Cited By ~ 2

Author(s):

Evan Mayer ◽

Patricia Dörr de Quadros ◽

Roberta Fulthorpe

Keyword(s):

Arabidopsis Thaliana ◽

Plant Growth ◽

Root Growth ◽

Plant Growth Promotion ◽

Growth Promotion ◽

Plant Growth Promoting Bacteria ◽

Bacterial Endophytes ◽

Content Type ◽

Plant Growth Promoting ◽

Growth Promoting

ABSTRACT A collection of bacterial endophytes isolated from stem tissues of plants growing in soils highly contaminated with petroleum hydrocarbons were screened for plant growth-promoting capabilities. Twenty-seven endophytic isolates significantly improved the growth of Arabidopsis thaliana plants in comparison to that of uninoculated control plants. The five most beneficial isolates, one strain each of Curtobacterium herbarum, Paenibacillus taichungensis, and Rhizobium selenitireducens and two strains of Plantibacter flavus were further examined for growth promotion in Arabidopsis, lettuce, basil, and bok choy plants. Host-specific plant growth promotion was observed when plants were inoculated with the five bacterial strains. P. flavus strain M251 increased the total biomass and total root length of Arabidopsis plants by 4.7 and 5.8 times, respectively, over that of control plants and improved lettuce and basil root growth, while P. flavus strain M259 promoted Arabidopsis shoot and root growth, lettuce and basil root growth, and bok choy shoot growth. A genome comparison between P. flavus strains M251 and M259 showed that both genomes contain up to 70 actinobacterial putative plant-associated genes and genes involved in known plant-beneficial pathways, such as those for auxin and cytokinin biosynthesis and 1-aminocyclopropane-1-carboxylate deaminase production. This study provides evidence of direct plant growth promotion by Plantibacter flavus. IMPORTANCE The discovery of new plant growth-promoting bacteria is necessary for the continued development of biofertilizers, which are environmentally friendly and cost-efficient alternatives to conventional chemical fertilizers. Biofertilizer effects on plant growth can be inconsistent due to the complexity of plant-microbe interactions, as the same bacteria can be beneficial to the growth of some plant species and neutral or detrimental to others. We examined a set of bacterial endophytes isolated from plants growing in a unique petroleum-contaminated environment to discover plant growth-promoting bacteria. We show that strains of Plantibacter flavus exhibit strain-specific plant growth-promoting effects on four different plant species.

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Quorum Sensing and Indole-3-Acetic Acid Degradation Play a Role in Colonization and Plant Growth Promotion of Arabidopsis thaliana by Burkholderia phytofirmans PsJN

Molecular Plant-Microbe Interactions ◽

10.1094/mpmi-10-12-0241-r ◽

2013 ◽

Vol 26 (5) ◽

pp. 546-553 ◽

Cited By ~ 85

Author(s):

Ana Zúñiga ◽

María Josefina Poupin ◽

Raúl Donoso ◽

Thomas Ledger ◽

Nicolás Guiliani ◽

...

Keyword(s):

Arabidopsis Thaliana ◽

Acetic Acid ◽

Quorum Sensing ◽

Plant Growth ◽

Growth Promotion ◽

Auxin Signaling ◽

Plant Growth Promoting ◽

Growth Promoting ◽

Indole 3 Acetic Acid ◽

Burkholderia Phytofirmans Psjn

Although not fully understood, molecular communication in the rhizosphere plays an important role regulating traits involved in plant–bacteria association. Burkholderia phytofirmans PsJN is a well-known plant-growth-promoting bacterium, which establishes rhizospheric and endophytic colonization in different plants. A competent colonization is essential for plant-growth-promoting effects produced by bacteria. Using appropriate mutant strains of B. phytofirmans, we obtained evidence for the importance of N-acyl homoserine lactone-mediated (quorum sensing) cell-to-cell communication in efficient colonization of Arabidopsis thaliana plants and the establishment of a beneficial interaction. We also observed that bacterial degradation of the auxin indole-3-acetic acid (IAA) plays a key role in plant-growth-promoting traits and is necessary for efficient rhizosphere colonization. Wildtype B. phytofirmans but not the iacC mutant in IAA mineralization is able to restore promotion effects in roots of A. thaliana in the presence of exogenously added IAA, indicating the importance of this trait for promoting primary root length. Using a transgenic A. thaliana line with suppressed auxin signaling (miR393) and analyzing the expression of auxin receptors in wild-type inoculated plants, we provide evidence that auxin signaling in plants is necessary for the growth promotion effects produced by B. phytofirmans. The interplay between ethylene and auxin signaling was also confirmed by the response of the plant to a 1-aminocyclopropane-1-carboxylate deaminase bacterial mutant strain.

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Characterization of Selected Plant Growth-Promoting Rhizobacteria and Their Non-Host Growth Promotion Effects

Microbiology Spectrum ◽

10.1128/spectrum.00279-21 ◽

2021 ◽

Author(s):

Di Fan ◽

Donald L. Smith

Keyword(s):

Arabidopsis Thaliana ◽

Plant Growth ◽

Plant Growth Promotion ◽

Growth Promotion ◽

Plant Growth Promoting Rhizobacteria ◽

Content Type ◽

Host Growth ◽

Plant Growth Promoting ◽

Growth Promoting

There are pressing needs to reduce the use of agrochemicals, and PGPR are receiving increasing interest in plant growth promotion and disease protection. This study follows up our previous report that the four newly isolated rhizobacteria promote the growth of Arabidopsis thaliana .

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Humic substances isolated from residues of sugar cane industry as root growth promoter

Scientia Agricola ◽

10.1590/s0103-90162010000200012 ◽

2010 ◽

Vol 67 (2) ◽

pp. 206-212 ◽

Cited By ~ 13

Author(s):

Jader Galba Busato ◽

Daniel Basílio Zandonadi ◽

Leonardo Barros Dobbss ◽

Arnoldo Rocha Façanha ◽

Luciano Pasqualoto Canellas

Keyword(s):

Plant Growth ◽

Root Growth ◽

Atpase Activity ◽

Humic Substances ◽

Root Development ◽

Filter Cake ◽

Growth Promoter ◽

Plasma Membrane Atpase ◽

Plant Growth Promoting ◽

Growth Promoting

Plant growth promoting substances are widely used in modern agriculture. Several products in the market are humic substances isolated from different sources. The filter cake, a residue of sugar production, is a rich and renewable source of organic matter and these characteristics place the filter cake as a possible source of plant growth promoting substances. Humic acids (HA) from filter cake were characterized, and their effects as root growth promoters were evaluated. Chemical features of the HA were evaluated through elemental composition, acidic functional groups, E4/E6 ratio and infrared spectroscopy analyzes. The biological activity of the HA was assessed using root architecture parameters and the P-type H+-ATPase activity. The lateral root development was directly related to the stimulation of plasma membrane ATPase activity. The ability of HA to promote root development indicate that HA from filter cake can be used as environmental plant growth stimulators.

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Rhizobacterial Inoculants Increase Root and Shoot Growth in ‘Tifway’ Hybrid Bermudagrass

Journal of Environmental Horticulture ◽

10.24266/0738-2898.32.3.149 ◽

2014 ◽

Vol 32 (3) ◽

pp. 149-154 ◽

Cited By ~ 2

Author(s):

R. Murphey Coy ◽

David W. Held ◽

Joseph W. Kloepper

Keyword(s):

Plant Growth ◽

Root Growth ◽

Growth Promotion ◽

Dry Weight ◽

Plant Growth Promoting Rhizobacteria ◽

Bacterial Strains ◽

Agronomic Crops ◽

Plant Growth Promoting ◽

Bacterial Treatment ◽

Growth Promoting

Plant growth-promoting rhizobacteria (PGPR) are non-pathogenic, beneficial bacteria that colonize seeds and roots of plants and enhance plant growth. Although there has been extensive PGPR research with agronomic crops, there has been little emphasis on development of PGPR for grasses in pastures or as turf. Accordingly, experiments were conducted to evaluate novel bacterial inoculants for growth promotion in ‘Tifway’ hybrid bermudagrass. Replicated laboratory and greenhouse experiments evaluated effects of various PGPR mixtures, each with 3 to 5 PGPR strains and applied as weekly root inoculations, in comparison to nontreated plants. Growth promotion was assessed by measuring foliar growth from 3 to 8 wk and root growth at 8 wk after the first treatment. In all experiments, at least one bacterial treatment of bermudagrass resulted in significantly increased top growth and greater root growth (length, surface area, volume, or dry weight). PGPR blends 20 and MC3 caused the greatest growth promotion of roots and shoots. These results suggest that the bacterial strains could be used in strategies to reduce nitrogen or water inputs to turf.

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Growth promotion and root development of Nicotiana tabacum L. by plant growth promoting fungi (PGPF)

Journal of Plant Biotechnology ◽

10.5010/jpb.2020.47.4.337 ◽

2020 ◽

Vol 47 (4) ◽

pp. 337-344

Author(s):

Eunhye Hong ◽

Jinok Lee ◽

Sujung Kim ◽

Hualin Nie ◽

Young-Nam Kim ◽

...

Keyword(s):

Nicotiana Tabacum ◽

Plant Growth ◽

Root Development ◽

Growth Promotion ◽

Nicotiana Tabacum L ◽

Plant Growth Promoting ◽

Growth Promoting

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Plant growth promoting rhizobacteria and their biological properties for soil enrichment and growth promotion

Journal of Plant Nutrition ◽

10.1080/01904167.2021.1952221 ◽

2021 ◽

pp. 1-27

Author(s):

Anjali Chauhan ◽

Raj Saini ◽

Jagjeet Chand Sharma

Keyword(s):

Plant Growth ◽

Growth Promotion ◽

Plant Growth Promoting Rhizobacteria ◽

Biological Properties ◽

Soil Enrichment ◽

Plant Growth Promoting ◽

Growth Promoting

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The Root Microbiome of Salicornia ramosissima as a Seedbank for Plant-Growth Promoting Halotolerant Bacteria

Applied Sciences ◽

10.3390/app11052233 ◽

2021 ◽

Vol 11 (5) ◽

pp. 2233

Author(s):

Maria J. Ferreira ◽

Angela Cunha ◽

Sandro Figueiredo ◽

Pedro Faustino ◽

Carla Patinha ◽

...

Keyword(s):

Plant Growth ◽

Plant Growth Promotion ◽

Growth Promotion ◽

Cultivated Plants ◽

Plant Growth Promoting Bacteria ◽

Crop Cultivation ◽

Halotolerant Bacteria ◽

Salicornia Ramosissima ◽

Plant Growth Promoting ◽

Growth Promoting

Root−associated microbial communities play important roles in the process of adaptation of plant hosts to environment stressors, and in this perspective, the microbiome of halophytes represents a valuable model for understanding the contribution of microorganisms to plant tolerance to salt. Although considered as the most promising halophyte candidate to crop cultivation, Salicornia ramosissima is one of the least-studied species in terms of microbiome composition and the effect of sediment properties on the diversity of plant-growth promoting bacteria associated with the roots. In this work, we aimed at isolating and characterizing halotolerant bacteria associated with the rhizosphere and root tissues of S. ramosissima, envisaging their application in saline agriculture. Endophytic and rhizosphere bacteria were isolated from wild and crop cultivated plants, growing in different estuarine conditions. Isolates were identified based on 16S rRNA sequences and screened for plant-growth promotion traits. The subsets of isolates from different sampling sites were very different in terms of composition but consistent in terms of the plant-growth promoting traits represented. Bacillus was the most represented genus and expressed the wider range of extracellular enzymatic activities. Halotolerant strains of Salinicola, Pseudomonas, Oceanobacillus, Halomonas, Providencia, Bacillus, Psychrobacter and Brevibacterium also exhibited several plant-growth promotion traits (e.g., 3-indole acetic acid (IAA), 1-aminocyclopropane-1-carboxylic acid (ACC) deaminase, siderophores, phosphate solubilization). Considering the taxonomic diversity and the plant-growth promotion potential of the isolates, the collection represents a valuable resource that can be used to optimize the crop cultivation of Salicornia under different environmental conditions and for the attenuation of salt stress in non-halophytes, considering the global threat of arable soil salinization.

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The Effects of Plant Growth-Promoting Bacteria with Biostimulant Features on the Growth of a Local Onion Cultivar and a Commercial Zucchini Variety

Agronomy ◽

10.3390/agronomy11050888 ◽

2021 ◽

Vol 11 (5) ◽

pp. 888

Author(s):

Giorgia Novello ◽

Patrizia Cesaro ◽

Elisa Bona ◽

Nadia Massa ◽

Fabio Gosetti ◽

...

Keyword(s):

Plant Growth ◽

Growth Promotion ◽

Global Market ◽

Plant Growth Promoting Bacteria ◽

Bacterial Strains ◽

Mineral Concentration ◽

Positive Effects ◽

Plant Growth Promoting ◽

Onion Cultivar ◽

Growth Promoting

The reduction of chemical inputs due to fertilizer and pesticide applications is a target shared both by farmers and consumers in order to minimize the side effects for human and environmental health. Among the possible strategies, the use of biostimulants has become increasingly important as demonstrated by the fast growth of their global market and by the increased rate of registration of new products. In this work, we assessed the effects of five bacterial strains (Pseudomonas fluorescens Pf4, P. putida S1Pf1, P. protegens Pf7, P. migulae 8R6, and Pseudomonas sp. 5Vm1K), which were chosen according to their previously reported plant growth promotion traits and their positive effects on fruit/seed nutrient contents, on a local onion cultivar and on zucchini. The possible variations induced by the inoculation with the bacterial strains on the onion nutritional components were also evaluated. Inoculation resulted in significant growth stimulation and improvement of the mineral concentration of the onion bulb, induced particularly by 5Vm1K and S1Pf1, and in different effects on the flowering of the zucchini plants according to the bacterial strain. The present study provides new information regarding the activity of the five plant growth-promoting bacteria (PGPB) strains on onion and zucchini, two plant species rarely considered by the scientific literature despite their economic relevance.

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