Response of forage quality in Persian clover upon co-inoculation with native Rhizobium leguminosarum symbiovar (sv.) trifoli RTB3 and plant-growth promoting Pseudomonas florescence 11168 under different levels of chemical fertilizers

Rapeseed (Brassica napus L.) is an important crop worldwide, due to its multiple uses, such as a human food, animal feed and a bioenergetic crop. Traditionally, its cultivation is based on the use of chemical fertilizers, known to lead to several negative effects on human health and the environment. Plant growth-promoting bacteria may be used to reduce the need for chemical fertilizers, but efficient bacteria in controlled conditions frequently fail when applied to the fields. Bacterial endophytes, protected from the rhizospheric competitors and extreme environmental conditions, could overcome those problems and successfully promote the crops under field conditions. Here, we present a screening process among rapeseed bacterial endophytes to search for an efficient bacterial strain, which could be developed as an inoculant to biofertilize rapeseed crops. Based on in vitro, in planta, and in silico tests, we selected the strain Pseudomonas brassicacearum CDVBN10 as a promising candidate; this strain produces siderophores, solubilizes P, synthesizes cellulose and promotes plant height in 5 and 15 days-post-inoculation seedlings. The inoculation of strain CDVBN10 in a field trial with no addition of fertilizers showed significant improvements in pod numbers, pod dry weight and shoot dry weight. In addition, metagenome analysis of root endophytic bacterial communities of plants from this field trial indicated no alteration of the plant root bacterial microbiome; considering that the root microbiome plays an important role in plant fitness and development, we suggest this maintenance of the plant and its bacterial microbiome homeostasis as a positive result. Thus, Pseudomonas brassicacearum CDVBN10 seems to be a good biofertilizer to improve canola crops with no addition of chemical fertilizers; this the first study in which a plant growth-promoting (PGP) inoculant specifically designed for rapeseed crops significantly improves this crop’s yields in field conditions.

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Rhizobium leguminosarum as a plant growth-promoting rhizobacterium: direct growth promotion of canola and lettuce

Canadian Journal of Microbiology ◽

10.1139/m96-040 ◽

1996 ◽

Vol 42 (3) ◽

pp. 279-283 ◽

Cited By ~ 129

Author(s):

T. C. Noel ◽

C. Sheng ◽

C. K. Yost ◽

R. P. Pharis ◽

M. F. Hynes

Keyword(s):

Acetic Acid ◽

Plant Growth ◽

Rhizobium Leguminosarum ◽

Growth Promotion ◽

Plant Growth Promoting Rhizobacteria ◽

Plant Growth Promoting ◽

Direct Growth ◽

Early Seedling ◽

Growth Promoting ◽

Indole 3 Acetic Acid

Early seedling root growth of the nonlegumes canola (Brassica campestris cv. Tobin, Brassica napus cv. Westar) and lettuce (Lactuca saliva cv. Grand Rapids) was significantly promoted by inoculation of seeds with certain strains of Rhizobium leguminosarum, including nitrogen- and nonnitrogen-fixing derivatives under gnotobiotic conditions. The growfh-promotive effect appears to be direct, with possible involvement of the plant growth regulators indole-3-acetic acid and cytokinin. Auxotrophic Rhizobium mutants requiring tryptophan or adenosine (precursors for indole-3-acetic acid and cytokinin synthesis, respectively) did not promote growth to the extent of the parent strain. The findings of this study demonstrate a new facet of the Rhizobium–plant relationship and that Rhizobium leguminosarum can be considered a plant growth-promoting rhizobacterium (PGPR).Key words: Rhizobium, plant growth-promoting rhizobacteria, PGPR, indole-3-acetic acid, cytokinin, roots, auxotrophic mutants.

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Effets de l'inoculation avec des souches deRhizobium leguminosarumbiovartrifoliisur la croissance du blé dans deux sols du Maroc

Canadian Journal of Microbiology ◽

10.1139/w01-068 ◽

2001 ◽

Vol 47 (6) ◽

pp. 590-593 ◽

Cited By ~ 24

Author(s):

Abdelaly Hilali ◽

Danielle Prévost ◽

William J Broughton ◽

Hani Antoun

Keyword(s):

Plant Growth ◽

Dry Matter ◽

Rhizobium Leguminosarum ◽

Agricultural Soils ◽

Plant Growth Promoting Rhizobacteria ◽

Silty Clay ◽

Rotation System ◽

Plant Growth Promoting ◽

Growth Promoting ◽

Pgpr Activity

One hundred strains of Rhizobium leguminosarum bv. trifolii were isolated from roots of wheat cultivated in rotation with clover in two different regions of Morocco. The isolates were first screened for their effect on the growth of the cultivar Rihane of wheat cultivated in an agricultural soil under greenhouse conditions. After 5 weeks of growth, 14 strains stimulating the fresh or dry matter yield of shoots were selected and used in a second pot inoculation trial performed with two different agricultural soils. The results show that the strains behaved differently according to the soil used. In the loamy sand Rabat, strain IAT 168 behaved potentially like a plant growth promoting rhizobacteria (PGPR), as indicated by the 24% increases (P < 0.1) observed in wheat shoot dry matter and grain yields. In the silty clay Merchouch, no PGPR activity was observed, and 6 strains showed a significant deleterious effect on yields. These observations suggest that it is very important in a crop rotation system to choose a R. leguminosarum bv. trifolii strain that is effective with clover and shows PGPR activity with wheat to avoid deleterious effects on wheat yields.Key words: deleterious bacteria, PGPR (plant growth promoting rhizobacteria), Trifolium alexandrinum, Triticum aestivum.

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Effect of 2,4-D and inoculation with Azorhizobium caulinodans on maize

Acta Agronomica Hungarica ◽

10.1556/aagr.54.2006.1.12 ◽

2006 ◽

Vol 54 (1) ◽

pp. 121-125 ◽

Cited By ~ 1

Author(s):

S. P. Saikia ◽

V. Jain ◽

G. C. Srivastava ◽

...

Keyword(s):

Plant Growth ◽

Nitrate Reductase Activity ◽

Reductase Activity ◽

Azorhizobium Caulinodans ◽

Chemical Fertilizers ◽

Promoting Effect ◽

Chemical Fertilization ◽

Plant Growth Promoting ◽

Growth Promoting ◽

Produce Plant

Research over the last few years has shown that inoculation with nitrogen-fixing bacteria of the genus Azorhizobium presents an alternative for (or supplement to) chemical fertilization, mainly due to the capability of the bacteria to produce plant growth- promoting hormones. The Azorhizobium caulinodans strain ORS 571 in combination with 2,4-D was able to colonize the root interior of an Indian maize cultivar. After transplanting to pots, it was noticed that nodulated and Azorhizobium -treated plants showed higher chlorophyll content in the leaf and enhanced nitrate reductase activity, leading to higher yield as compared to the control plants (non-nodulated). A plant growth-promoting effect was clearly visible in all inoculated plants examined. nodulated plants treated with Azorhizobium had higher physiological activities as compared to plants treated only with Azorhizobium . Azorhizobium therefore creates potentially better symbiosis in the form of para -nodules and promotes a higher level of nitrogen fixation, leading to better growth and plant development, with reduced requirements for chemical fertilizers.

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Synergistic interaction of Rhizobium leguminosarum bv. viciae and arbuscular mycorrhizal fungi as a plant growth promoting biofertilizers for faba bean (Vicia faba L.) in alkaline soil

Microbiological Research ◽

10.1016/j.micres.2013.07.007 ◽

2014 ◽

Vol 169 (1) ◽

pp. 49-58 ◽

Cited By ~ 76

Author(s):

Mohamed Hemida Abd-Alla ◽

Abdel-Wahab Elsadek El-Enany ◽

Nivien Allam Nafady ◽

David Mamdouh Khalaf ◽

Fatthy Mohamed Morsy

Keyword(s):

Plant Growth ◽

Arbuscular Mycorrhizal Fungi ◽

Faba Bean ◽

Mycorrhizal Fungi ◽

Rhizobium Leguminosarum ◽

Arbuscular Mycorrhizal ◽

Alkaline Soil ◽

Vicia Faba L ◽

Plant Growth Promoting ◽

Growth Promoting

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Plant Growth Promoting Rhizobacteria (PGPRs) Alter Plant Host Somatic Mutation Frequencies

International Journal of Plant and Environment ◽

10.18811/ijpen.v5i03.2 ◽

2019 ◽

Vol 5 (03) ◽

pp. 149-154

Author(s):

Jasmine M. Shah ◽

Aparna C. ◽

Pallavi S. Nair

Keyword(s):

Plant Growth ◽

Somatic Mutation ◽

Post Infection ◽

Rhizobium Leguminosarum ◽

Somatic Mutations ◽

Plant Growth Promoting Rhizobacteria ◽

Pathogenic Strain ◽

Plant Host ◽

Plant Growth Promoting ◽

Growth Promoting

Plant growth promoting rhizobacteria (PGPRs) are a group of soil bacteria which can induce positive growth in plants by different mechanisms. This work intends to find the effect of PGPRs on two classes of somatic mutations in the host, frame shift mutation (FSM) and somatic homologous recombination (SHR) and, compare the same with that of a pathogen. Somatic mutations in plants are important as they are an adaptation strategy to overcome stressful conditions and also get passed on to the next generations. The mutation detector Arabidopsis thaliana lines carrying a non-functional β-glucuronidase gene (GUS) were used to score the mutation events. One day-old mutant seedlings were co-cultivated with the PGPRs (Rhizobium leguminosarum and Pseudomonas fluorescens) and the pathogenic strain (P. syringae) for two different post-infection durations (4 h and 48 h). A reversion of the mutated GUS to its functional form resulted in blue spots in the host plant. Based on the number of blue spots seen, the mutation frequencies were estimated. An increase in FSM was observed in plants co-cultivated with R. leguminosarum for 4 h as well as 48 h. R. leguminosarum suppressed SHR frequency 4 h-post infection, which significantly increased at 48 h. In contrast, P. fluorescens infection lead to a temporal suppression of FSM and induction of SHR at 4 h. Subsequently, the SHR rates reduced significantly, i.e. lower than the uninfected controls at 48 h. The pathogenic strain P. syringae temporally increased FSM in plants and also enhanced SHR rates in plants 4 h post-infection, which also subsequently reduced 48 h post infection. To the best of our knowledge, there are no other reports comparing the effect of PGPRs on host somatic mutation rates.

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Distinct Root Microbial Communities in Nature Farming Rice Harbor Bacterial Strains With Plant Growth-Promoting Traits

Frontiers in Sustainable Food Systems ◽

10.3389/fsufs.2020.629942 ◽

2021 ◽

Vol 4 ◽

Author(s):

Grace Flavyeliz Sinong ◽

Michiko Yasuda ◽

Yoshiyuki Nara ◽

Chol Gyu Lee ◽

Khondoker Mohammad Golam Dastogeer ◽

...

Keyword(s):

Plant Growth ◽

Farming Systems ◽

Farming System ◽

Bacterial Strains ◽

Chemical Fertilizers ◽

Distinct Root ◽

Rice Growth ◽

Plant Growth Promoting ◽

Growth Promoting ◽

Root Microbiome

A nature farming system is an ecological farming practice that entails cultivating crops without using chemical fertilizers and pesticides. To understand the diversity and functions of root microbiomes associated with nature farming systems, we compared the root microbial community of rice under nature farming conditions with those under conventional farming conditions. High-throughput amplicon analysis demonstrated a higher abundance and greater diversity of the root microbiome under unfertilized nature farming conditions than under conventional conditions. The application of chemical fertilizers reduced the microbial diversity and abundance of some beneficial taxa important for plant growth and health. Subsequently, we isolated and identified 46 endo- and epiphytic bacteria from rice roots grown under nature farming conditions and examined their plant growth-promoting activity. Six potential isolates were selected for plant growth assessment in insoluble P- and K-containing media. Most of the isolates promoted rice growth, and Pseudomonas koreensis AEPR1 was able to enhance rice growth significantly in both insoluble P- and K-containing media. Our data indicated that nature farming systems create a distinct root microbiome that is comparatively more diverse and supports plant growth under low-input cultivation practices than under conventional practices. The potential isolates could be exploited as sources with potential applications in sustainable agriculture.

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