Inter-root movement of Azospirillum brasilense and subsequent root colonization of crop and weed seedlings growing in soil

1995 ◽  
Vol 29 (3) ◽  
pp. 269-281 ◽  
Author(s):  
Y. Bashan ◽  
G. Holguin
Keyword(s):  
Azospirillum Brasilense ◽  
Root Colonization ◽  
Root Movement

scholarly journals Involvement of the Reserve Material Poly-β-Hydroxybutyrate in Azospirillum brasilense Stress Endurance and Root Colonization

2003 ◽  
Vol 69 (6) ◽  
pp. 3244-3250 ◽  
Author(s):  
Daniel Kadouri ◽  
Edouard Jurkevitch ◽  
Yaacov Okon
Keyword(s):  
Plant Growth ◽  
Mutant Strain ◽  
Azospirillum Brasilense ◽  
Type Strain ◽  
Wild Type Strain ◽  
Root Colonization ◽  
Cell Aggregation ◽  
Wild Type ◽  
Phb Production ◽  
Promote Plant Growth

ABSTRACT When grown under suboptimal conditions, rhizobacteria of the genus Azospirillum produce high levels of poly-β-hydroxybutyrate (PHB). Azospirillum brasilense strain Sp7 and a phbC (PHB synthase) mutant strain in which PHB production is impaired were evaluated for metabolic versatility, for the ability to endure various stress conditions, for survival in soil inoculants, and for the potential to promote plant growth. The carbon source utilization data were similar for the wild-type and mutant strains, but the generation time of the wild-type strain was shorter than that of the mutant strain with all carbon sources tested. The ability of the wild type to endure UV irradiation, heat, osmotic pressure, osmotic shock, and desiccation and to grow in the presence of hydrogen peroxide was greater than that of the mutant strain. The motility and cell aggregation of the mutant strain were greater than the motility and cell aggregation of the wild type. However, the wild type exhibited greater chemotactic responses towards attractants than the mutant strain exhibited. The wild-type strain exhibited better survival than the mutant strain in carrier materials used for soil inoculants, but no difference in the ability to promote plant growth was detected between the strains. In soil, the two strains colonized roots to the same extent. It appears that synthesis and utilization of PHB as a carbon and energy source by A. brasilense under stress conditions favor establishment of this bacterium and its survival in competitive environments. However, in A. brasilense, PHB production does not seem to provide an advantage in root colonization under the conditions tested.

Nonspecific responses in plant growth, yield, and root colonization of noncereal crop plants to inoculation with Azospirillum brasilense Cd

1989 ◽  
Vol 67 (5) ◽  
pp. 1317-1324 ◽  
Author(s):  
Y. Bashan ◽  
Y. Ream ◽  
Hanna Levanony ◽  
A. Sade
Keyword(s):  
Plant Growth ◽  
Plant Species ◽  
Azospirillum Brasilense ◽  
Root Colonization ◽  
Growth Parameters ◽  
Growth Yield ◽  
Dry Weight ◽  
Plant Response ◽  
Crop Plants ◽  
High Yield

Inoculation of seven different crop plant species by Azospirillum brasilense Cd resulted in an increase in plant yield, as well as in changes in several other plant parameters, in tomato, eggplant, pepper, and cotton plants. Analysis of 56 different experiments revealed that the rate of success (positive plant response) ranged from 71 to 75 %. The dry weight of plants and yield responses ranged from significantly high yield increases to negligible or no response in similarly performed experiments. The average increases in yield in the positive response experiments were 30, 23, 18, and 16% for tomato, eggplant, pepper, and cotton, respectively. Significant earlier maturation was also detected in the four responding plant species. The response of other plant growth parameters varied between plant species. The level of root colonization by A. brasilense Cd was similar in all four plant species, i.e. root population size of 5 × 105 cfu/g fresh weight root. It is suggested that inoculation of noncereal crop plants by the cereal-root originate A. brasilense Cd is nonspecific with inconsistency in plant response to inoculation.

scholarly journals Azospirillum Brasilense And Zinc Rates Affecting Fungal Root Colonization and Yield of Cereal Crops in Succession Under Brazilian Cerrado Conditions

2021 ◽  
Author(s):  
Philippe Solano Toledo Silva ◽  
Ana Maria Rodrigues Cassiolato ◽  
Fernando Shintate Galindo ◽  
Arshad Jalal ◽  
Thiago Assis Rodrigues Nogueira ◽  
...  
Keyword(s):  
Grain Yield ◽  
Mycorrhizal Fungi ◽  
Azospirillum Brasilense ◽  
Root Colonization ◽  
Block Design ◽  
Wheat Yield ◽  
Arbuscular Mycorrhizal ◽  
Symbiotic Association ◽  
Brazilian Cerrado ◽  
Randomized Block Design

Abstract Soil and plant beneficial microbes capitalize plant nutrition through successful colonization in roots rhizosphere which could sustainably increase cereal production. Zinc (Zn) is intensively reported a deficient nutrient for maize and wheat production in Brazilian Cerrado, which could be sustainably managed by beneficial microorganisms and their symbiotic association with other microorganisms like arbuscular mycorrhizal fungi (AMF) and dark septate endophytes (DSE). The objective of this study was to evaluate the effect of Azospirillum brasilense inoculation and residual Zn rates on root colonization and grain yield of maize and wheat in succession under Brazilian Cerrado conditions. These experiments were conducted in a randomized block design with four replications and arranged in a 5x2 factorial scheme. The treatments were consisted of five Zn rates (0, 2, 4, 6 and 8 kg ha-1) applied from zinc sulfate in maize and residual on wheat, and without and with seed inoculation of A. brasilense. Both crops were evaluated for root colonization of AMF and DSE, number of spores of AMF, quantification of CO2-C and grain yield. Colonization by AMF and DSE were significantly increased with interaction of Zn rates and inoculation treatments. The inoculation of A. brasilense favored root AMF and DSE colonization while increasing Zn rates by 4 kg ha-1 for maize and while 2 and 4 kg ha-1 Zn in residual for wheat reduced these colonizations. The inoculation did not influence spore production and CO2-C in both crops while maize-wheat yield were increased with Zn rates up to 4 kg ha-1 in edaphoclimatic condition of Brazilian Cerrado.

scholarly journals An Energy Taxis Transducer Promotes Root Colonization by Azospirillum brasilense

2004 ◽  
Vol 186 (19) ◽  
pp. 6595-6604 ◽  
Author(s):  
Suzanne E. Greer-Phillips ◽  
Bonnie B. Stephens ◽  
Gladys Alexandre
Keyword(s):  
Azospirillum Brasilense ◽  
Root Colonization ◽  
Bacterial Metabolism ◽  
Key Factors ◽  
Histidine Kinases ◽  
Temporal Gradient ◽  
Qualitative And Quantitative ◽  
Energy Taxis ◽  
Locomotor Control ◽  
Conserved Domain

ABSTRACT Motility responses triggered by changes in the electron transport system are collectively known as energy taxis. In Azospirillum brasilense, energy taxis was shown to be the principal form of locomotor control. In the present study, we have identified a novel chemoreceptor-like protein, named Tlp1, which serves as an energy taxis transducer. The Tlp1 protein is predicted to have an N-terminal periplasmic region and a cytoplasmic C-terminal signaling module homologous to those of other chemoreceptors. The predicted periplasmic region of Tlp1 comprises a conserved domain that is found in two types of microbial sensory receptors: chemotaxis transducers and histidine kinases. However, the function of this domain is currently unknown. We characterized the behavior of a tlp1 mutant by a series of spatial and temporal gradient assays. The tlp1 mutant is deficient in (i) chemotaxis to several rapidly oxidizable substrates, (ii) taxis to terminal electron acceptors (oxygen and nitrate), and (iii) redox taxis. Taken together, the data strongly suggest that Tlp1 mediates energy taxis in A. brasilense. Using qualitative and quantitative assays, we have also demonstrated that the tlp1 mutant is impaired in colonization of plant roots. This finding supports the hypothesis that energy taxis and therefore bacterial metabolism might be key factors in determining host specificity in Azospirillum-grass associations.

Wheat root colonization by Azospirillum brasilense strains with different motility

Microbiology ◽  
2010 ◽  
Vol 79 (5) ◽  
pp. 688-695 ◽  
Author(s):  
A. V. Shelud’ko ◽  
A. A. Shirokov ◽  
M. K. Sokolova ◽  
O. I. Sokolov ◽  
L. P. Petrova ◽  
...  
Keyword(s):  
Azospirillum Brasilense ◽  
Root Colonization ◽  
Wheat Root
Sign in / Sign up

Export Citation Format

Share Document