scholarly journals Quantification of Azospirillum brasilense FP2 Bacteria in Wheat Roots by Strain-Specific Quantitative PCR

2015 ◽  
Vol 81 (19) ◽  
pp. 6700-6709 ◽  
Author(s):  
Maria Isabel Stets ◽  
Sylvia Maria Campbell Alqueres ◽  
Emanuel Maltempi Souza ◽  
Fábio de Oliveira Pedrosa ◽  
Michael Schmid ◽  
...  

ABSTRACTAzospirillumis a rhizobacterial genus containing plant growth-promoting species associated with different crops worldwide.Azospirillum brasilensestrains exhibit a growth-promoting effect by means of phytohormone production and possibly by N2fixation. However, one of the most important factors for achieving an increase in crop yield by plant growth-promoting rhizobacteria is the survival of the inoculant in the rhizosphere, which is not always achieved. The objective of this study was to develop quantitative PCR protocols for the strain-specific quantification ofA. brasilenseFP2. A novel approach was applied to identify strain-specific DNA sequences based on a comparison of the genomic sequences within the same species. The draft genome sequences ofA. brasilenseFP2 and Sp245 were aligned, and FP2-specific regions were filtered and checked for other possible matches in public databases. Strain-specific regions were then selected to design and evaluate strain-specific primer pairs. The primer pairs AzoR2.1, AzoR2.2, AzoR5.1, AzoR5.2, and AzoR5.3 were specific for theA. brasilenseFP2 strain. These primer pairs were used to monitor quantitatively the population ofA. brasilensein wheat roots under sterile and nonsterile growth conditions. In addition, coinoculations with other plant growth-promoting bacteria in wheat were performed under nonsterile conditions. The results showed thatA. brasilenseFP2 inoculated into wheat roots is highly competitive and achieves high cell numbers (∼107CFU/g [fresh weight] of root) in the rhizosphere even under nonsterile conditions and when coinoculated with other rhizobacteria, maintaining the population at rather stable levels for at least up to 13 days after inoculation. The strategy used here can be applied to other organisms whose genome sequences are available.

2019 ◽  
Vol 8 (31) ◽  
Author(s):  
Chhaya Singh ◽  
Parul Pandey ◽  
Durgesh Narain Singh ◽  
Rachna Pandey ◽  
Ajit Kumar Shasany ◽  
...  

Azospirillum brasilense is used worldwide as a plant growth-promoting inoculant for agricultural crops. To understand how the genomes of Indian strains of A. brasilense compare with their South American counterparts, we determined the whole-genome sequences of four strains of A. brasilense isolated from the rhizosphere of grasses from India.


2020 ◽  
Vol 9 (20) ◽  
Author(s):  
Becky N. Aloo ◽  
Ernest R. Mbega ◽  
Billy A. Makumba ◽  
Ines Friedrich ◽  
Robert Hertel ◽  
...  

We present here the complete genome sequences of plant growth-promoting Klebsiella sp. strain MPUS7, Serratia sp. strain NGAS9, and Citrobacter sp. strain LUTT5, isolated from rhizosphere soils and tubers of potato (Solanum tuberosum L.) plants growing in the northern and southern highlands of Tanzania.


2021 ◽  
Vol 10 (11) ◽  
Author(s):  
Alexey M. Afonin ◽  
Emma S. Gribchenko ◽  
Gulnar A. Akhtemova ◽  
Yuri V. Laktionov ◽  
Andrej P. Kozhemyakov ◽  
...  

ABSTRACT Plants can form various beneficial associations with soil microorganisms, such as associations with plant growth-promoting bacteria (PGPB). In this work, we report the full-genome sequence of the component of Mysorin biopreparation, identified as Microbacterium hominis, consisting of a single 3.5-Mbp circular chromosome.


2019 ◽  
Vol 85 (19) ◽  
Author(s):  
Evan Mayer ◽  
Patricia Dörr de Quadros ◽  
Roberta Fulthorpe

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.


2020 ◽  
Vol 2020 ◽  
pp. 1-8
Author(s):  
Mariana S. Santos ◽  
Artur B. L. Rondina ◽  
Marco A. Nogueira ◽  
Mariangela Hungria

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.


2018 ◽  
Vol 6 (12) ◽  
pp. e00104-18 ◽  
Author(s):  
Luz K. Medina-Cordoba ◽  
Aroon T. Chande ◽  
Lavanya Rishishwar ◽  
Leonard W. Mayer ◽  
Leonardo Mariño-Ramírez ◽  
...  

ABSTRACT Members of the Klebsiella genus promote plant growth. We report here draft whole-genome sequences for 15 Klebsiella sp. isolates from sugarcane fields in the Cauca Valley of Colombia. The genomes of these isolates were characterized as part of a broader effort to evaluate their utility as endemic plant growth-promoting biofertilizers.


2021 ◽  
Vol 10 (3) ◽  
Author(s):  
Pooja Ramadas ◽  
Dhruv Pathak ◽  
Prabhjeet Kaur

In today’s largely populated modern world, crop yield is becoming increasingly important. To increase crop yield, new modern technologies for farming are continuously being innovated. The aim of this study is the identification of Plant Growth Promoting Bacteria (PGPBs) and their properties. In order to conduct the experiment, soil samples were collected from the community garden LEAF (Local Ecology and Agriculture Fremont). These samples were grown in Luria Bertani agar plates, and the two bacterial strains that grew from them were analyzed to determine the species of the bacteria. Using a DNA extraction kit, DNA was extracted from the bacteria and then amplified versions were sent to RF Biotech for DNA sequencing. The DNA sequences were then used to determine that the two bacterial species in question are Bacillus cereus and Morganella morganii. Afterwards, multiple assays were used to measure the efficiency of each bacterial species to absorb various substances that would be helpful for plant growth. The aim of this research is to better understand which bacterial strains are beneficial for plants, and which are harmful. Through having greater zones of inhibition, the bacterial species M. morganii proved to be more efficient in the siderophore and phosphate solubilization assays. In contrast, the bacterial species B. cereus proved to be more efficient in the cellulase and amylase production assays. These results will assist LEAF in enriching their soil in order to increase their crop yields by creating an increase in concentration of advantageous bacteria and decrease that of detrimental bacteria.


mBio ◽  
2020 ◽  
Vol 11 (6) ◽  
pp. e03078-20
Author(s):  
Fernanda Plucani do Amaral ◽  
Thalita Regina Tuleski ◽  
Vania Carla Silva Pankievicz ◽  
Ryan A. Melnyk ◽  
Adam P. Arkin ◽  
...  

ABSTRACTThe plant rhizosphere harbors a diverse population of microorganisms, including beneficial plant growth-promoting bacteria (PGPB), that colonize plant roots and enhance growth and productivity. In order to specifically define bacterial traits that contribute to this beneficial interaction, we used high-throughput transposon mutagenesis sequencing (TnSeq) in two model root-bacterium systems associated with Setaria viridis: Azoarcus olearius DQS4T and Herbaspirillum seropedicae SmR1. This approach identified ∼100 significant genes for each bacterium that appeared to confer a competitive advantage for root colonization. Most of the genes identified specifically in A. olearius encoded metabolism functions, whereas genes identified in H. seropedicae were motility related, suggesting that each strain requires unique functions for competitive root colonization. Genes were experimentally validated by site-directed mutagenesis, followed by inoculation of the mutated bacteria onto S. viridis roots individually, as well as in competition with the wild-type strain. The results identify key bacterial functions involved in iron uptake, polyhydroxybutyrate metabolism, and regulation of aromatic metabolism as important for root colonization. The hope is that by improving our understanding of the molecular mechanisms used by PGPB to colonize plants, we can increase the adoption of these bacteria in agriculture to improve the sustainability of modern cropping systems.IMPORTANCE There is growing interest in the use of associative, plant growth-promoting bacteria (PGPB) as biofertilizers to serve as a sustainable alternative for agriculture application. While a variety of mechanisms have been proposed to explain bacterial plant growth promotion, the molecular details of this process remain unclear. The current research supports the idea that PGPB use in agriculture will be promoted by gaining more knowledge as to how these bacteria colonize plants, promote growth, and do so consistently. Specifically, the research seeks to identify those bacterial genes involved in the ability of two, PGPB strains, Azoarcus olearius and Herbaspirillum seropedicae, to colonize the roots of the C4 model grass Setaria viridis. Applying a transposon mutagenesis (TnSeq) approach, we assigned phenotypes and function to genes that affect bacterial competitiveness during root colonization. The results suggest that each bacterial strain requires unique functions for root colonization but also suggests that a few, critical functions are needed by both bacteria, pointing to some common mechanisms. The hope is that such information can be exploited to improve the use and performance of PGPB in agriculture.


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