Effects of Plant Growth-Promoting Bacteria (PGPB) Inoculation on the Growth, Antioxidant Activity, Cu Uptake, and Bacterial Community Structure of Rape (Brassica napus L.) Grown in Cu-Contaminated Agricultural Soil

AbstractThe present study was carried out to investigate how plant growth-promoting bacteria (PGPB) influence plant growth and uptake of boron (B) and phosphorus (P) in rapeseed (Brassica napus). Rapeseed was subjected to control, B, P and B + P treatments, either with or without B. pumilus (PGPB) inoculation, and grown in pot culture for 6 weeks. In the absence of B. pumilus, the addition of B, P or both elements improved the growth of rapeseed compared with the control. Interestingly, B. pumilus inoculation inhibited plant growth and enhanced B uptake under B and B + P but not under control and P conditions. In addition, B. pumilus inoculation decreased the pH of soil under B and B + P supplies. Bacillus pumilus inoculation thus increased rapeseed B uptake and inhibited growth under B supply, which suggests that the effects of PGPB on rapeseed growth depend on the addition of B to soil. Bacillus pumilus inoculation may therefore be recommended for the enhancement of rapeseed B levels in B-deficient soils but not in B-sufficient ones.

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Selection of the Root Endophyte Pseudomonas brassicacearum CDVBN10 as Plant Growth Promoter for Brassica napus L. Crops

Agronomy ◽

10.3390/agronomy10111788 ◽

2020 ◽

Vol 10 (11) ◽

pp. 1788

Author(s):

Alejandro Jiménez-Gómez ◽

Zaki Saati-Santamaría ◽

Martin Kostovcik ◽

Raúl Rivas ◽

Encarna Velázquez ◽

...

Keyword(s):

Brassica Napus ◽

Plant Growth ◽

Dry Weight ◽

Bacterial Endophytes ◽

Chemical Fertilizers ◽

Brassica Napus L ◽

Bacterial Microbiome ◽

Plant Growth Promoting ◽

Growth Promoting ◽

Pseudomonas Brassicacearum

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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Assessment of the Capacity of Beneficial Bacterial Inoculants to Enhance Canola (Brassica napus L.) Growth under Low Water Activity

Agronomy ◽

10.3390/agronomy10091449 ◽

2020 ◽

Vol 10 (9) ◽

pp. 1449

Author(s):

Dasun Premachandra ◽

Lee Hudek ◽

Aydin Enez ◽

Ross Ballard ◽

Steve Barnett ◽

...

Keyword(s):

Brassica Napus ◽

Plant Growth ◽

Water Activity ◽

Production Costs ◽

Annual Rainfall ◽

Shoot Biomass ◽

Brassica Napus L ◽

Environmentally Sustainable ◽

Plant Growth Promoting ◽

Growth Promoting

Canola (Brassica napus L.) is the third largest crop produced in Australia after wheat and barley. For such crops, the variability of water access, reduced long-term annual rainfall and increasing water prices, higher overall production costs, and variability in production quantity and quality are driving the exploration of new tools to maintain production in an economical and environmentally sustainable way. Microorganisms associated with the rhizosphere have been shown to enhance plant growth and offer a potential way to maintain or even increase crop production quality and yield in an environmentally sustainable way. Here, seven bacterial isolates from canola rhizosphere samples are shown to enhance canola growth, particularly in low water activity systems. The seven strains all possessed commonly described plant growth promoting traits, including the ability to produce indole-3-acetic acid and 1-aminocyclopropane-1-carboxylate deaminase, and the capacity to solubilise nutrients (Fe2+/3+ and PO43−). When the isolates were inoculated at the time of sowing in pot-based systems with either sand or clay loam media, and in field trials, a significant increase in dry root and shoot biomass was recorded compared to uninoculated controls. It is likely that the strains’ plant growth promoting capacity under water stress is due to the combined effects of the bacterial phenotypes examined here.

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Effect of Irrigation Levels and Plant Growth Promoting Rhizobacteria on Yield, Some Physiological and Biochemical Indices of Rapeseed (Brassica napus L.)

Journal of Crop production and processing ◽

10.29252/jcpp.9.2.99 ◽

2019 ◽

Vol 9 (2) ◽

pp. 99-112

Author(s):

H. Vatan Doost ◽

R. Seyed Sharifi ◽

Y. Kheirizadeh Arough ◽

◽

...

Keyword(s):

Brassica Napus ◽

Plant Growth ◽

Plant Growth Promoting Rhizobacteria ◽

Brassica Napus L ◽

Plant Growth Promoting ◽

Growth Promoting ◽

Biochemical Indices ◽

Irrigation Levels ◽

Physiological And Biochemical

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Growth of canola (Brassica napus) in the presence of plant growth-promoting bacteria and either copper or polycyclic aromatic hydrocarbons

Canadian Journal of Microbiology ◽

10.1139/w05-094 ◽

2005 ◽

Vol 51 (12) ◽

pp. 1061-1069 ◽

Cited By ~ 130

Author(s):

M L.E Reed ◽

Bernard R Glick

Keyword(s):

Polycyclic Aromatic Hydrocarbons ◽

Brassica Napus ◽

Plant Growth ◽

Aromatic Hydrocarbons ◽

Contaminated Soils ◽

Plant Growth Promoting Bacteria ◽

Polycyclic Aromatic ◽

Plant Growth Promoting ◽

Growth Promoting ◽

Copper Contaminated

Growth of canola (Brassica napus) seeds treated with plant growth-promoting bacteria in copper-contaminated and polycyclic aromatic hydrocarbon (PAH)-contaminated soils was monitored. Pseudomonas asplenii AC, isolated from PAH-contaminated soil, was transformed to express a bacterial gene encoding 1-aminocyclopropane-1-carboxylate (ACC) deaminase, and both native and transformed bacteria were tested for growth promotion. Inoculation of seeds, grown in the presence of copper or creosote, with either native or transformed P. asplenii AC significantly increased root and shoot biomass. Native and transformed P. asplenii AC and transformed P. asplenii AC encapsulated in alginate were equally effective at promoting plant growth in copper-contaminated soils. In creosote-contaminated soils the native bacterium was the least effective, and the transformed encapsulated bacterium was the most effective in growth promotion.Key words: plant growth-promoting bacteria, phytoremediation, copper, polycyclic aromatic hydrocarbons, Brassica napus, ethylene, alginate encapsulation.

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