Changes in proton efflux of intact wheat roots induced by Azospirillum brasilense Cd

1989 ◽  
Vol 35 (7) ◽  
pp. 691-697 ◽  
Author(s):  
Yoav Bashan ◽  
Hanna Levanony ◽  
Girma Mitiku
Keyword(s):  
Azospirillum Brasilense ◽  
Logarithmic Phase ◽  
Partial Recovery ◽  
Regular Pattern ◽  
Fresh Weight ◽  
Proton Efflux ◽  
Proton Extrusion ◽  
Wheat Roots ◽  
Wheat Seedlings ◽  
Bacterial Cultures

Inoculation of wheat seedings with Azospirillum brasilense Cd increased proton efflux from the roots. Inoculation of seeds or young seedlings using bacterial cultures at the logarithmic phase of growth caused the strongest proton extrusion. The increased effect lasted up to 20 h. No difference was detected between inoculated and noninoculated plants 20 h after inoculation. Both inoculated and noninoculated plants decreased the final pH of the nutrient solution to 3.2 and had an average proton extrusion of 4.3 μmol H+ ∙ (g fresh weight)−1∙h−1. Azospirillum brasilense Cd inoculation of wheat roots in which proton efflux was inhibited by the addition of either nitrate, dicyclohexylcarbodiimide, or orthovanadate resulted in partial recovery of proton efflux activity in these roots. Inoculation of wheat seedlings also changed the regular pattern of root proton efflux over prolonged periods of time. It is suggested that A. brasilense Cd inoculation influenced membrane activity and subsequent proton efflux in roots of wheat seedlings.Key words: Azospirillum, plant–bacteria interaction, proton efflux, rhizosphere bacteria, Triticum aestivum, wheat.

Short exposure to Azospirillum brasilense Cd inoculation enhanced proton efflux of intact wheat roots

1990 ◽  
Vol 36 (6) ◽  
pp. 419-425 ◽  
Author(s):  
Yoav Bashan
Keyword(s):  
Azospirillum Brasilense ◽  
Optimal Level ◽  
Rhizosphere Bacteria ◽  
Short Exposure ◽  
Physiological Status ◽  
Bacterial Cells ◽  
Proton Efflux ◽  
Proton Extrusion ◽  
Wheat Roots ◽  
Wheat Seedlings

Inoculation of wheat seedlings with Azospirillum brasilense Cd significantly increased the proton efflux of the roots 5 h after inoculation compared with noninoculated plants. Removal of the bacterial cells from the root surface 2, 4, or 10 h after inoculation did not affect proton extrusion, which remained similar to the proton efflux of inoculated roots with a permanent A. brasilense Cd population. Proton efflux from roots after short exposure to A. brasilense Cd was directly related to the inoculation level and to the physiological status of the bacterial cells. Active bacteria, at an optimal level for inoculation (105–107 cfu∙mL−1), produced the most proton extrusion from roots. Stressed bacteria, i.e., bacteria exposed to starvation, 45 °C, anaerobic conditions, or a high level of streptomycin before inoculation, induced smaller but not statistically significant increases in proton efflux. Inoculation with dead A. brasilense Cd cells, cell-wall fragments, or several associative nonbeneficial rhizosphere bacteria belonging to other genera did not enhance the proton efflux compared with noninoculated plants. Continuous perfusion of the nutrient solution of plants while maintaining the bacterial cells in the root vicinity eliminated the proton efflux enhancement caused by A. brasilense Cd. Bacteria, regardless of species or stress conditions, in the absence of plants produced negligible proton efflux. It is suggested that short exposures of wheat roots to live A. brasilense Cd enhanced the proton efflux of roots, probably through the release of an as yet unidentified bacterial signal. Active metabolism of the bacterium is required for this enhancement, which is of a triggering nature. Key words: Azospirillum, beneficial bacteria, plant–bacteria interaction, proton efflux, rhizosphere bacteria, Triticum aestivum, wheat.

Azospirillum inoculation in pregerminating wheat seeds

1996 ◽  
Vol 42 (1) ◽  
pp. 83-86 ◽  
Author(s):  
Cecilia M. Creus ◽  
Rolando J. Sueldo ◽  
Carlos A. Barassi
Keyword(s):  
Triticum Aestivum ◽  
Azospirillum Brasilense ◽  
Dry Weight ◽  
The Other ◽  
Distilled Water ◽  
Fresh Weight ◽  
Bacterial Concentration ◽  
Wheat Seedlings ◽  
Viable Cells ◽  
Wheat Seeds

Azospirillum cells were inoculated in pregerminating wheat during seed imbibition. Surface-sterilized seeds of Triticum aestivum cv. Buck Pucará were sequentially soaked for 3 h in water and 3 h in the inoculum of 3 × 108Azospirillum brasilense Sp 245 cells∙mL−1, to allow bacteria to enter during imbibition. Germination and seedling growth were accomplished in sterile distilled water at 20 °C, in the dark. To compare with more traditional methods based on plant–Azospirillum colonization after germination, seedlings from noninoculated seeds were inoculated in parallel by immersing roots in the same inoculum, for the same period of time. Autoclaved inocula were used as controls in all cases. We observed about 5 × 108Azospirillum cells∙g−1 fresh weight in 11-day-old wheat seedlings inoculated before or after seed germination. However, roots from seed-inoculated seedlings had higher both bacterial concentration and length. On the other hand, seeds inoculated during imbibition and dried to 14% water content retained 3.7 × 106 viable cells∙g−1 dry weight up to 27 days. Moreover, seeds stored for 30 days were not only able to germinate but also to harbor over 106 cells∙g−1 fresh weight in roots after 7 days growth. Here we present the possibility of obtaining in a simple and inexpensive way, seeds containing high numbers of viable Azospirillum cells, which could avoid the use of external carriers or adhesives.Key words: Azospirillum, wheat, inoculation.

Effect of 24-epibrassinolide on localization of ABA, AZP, and dehydrins in wheat plant roots during dehydration

Biomics ◽  
2020 ◽  
Vol 12 (3) ◽  
pp. 329-336
Author(s):  
A.R. Lubyanova ◽  
F.M. Shakirova ◽  
M.V. Bezrukova
Keyword(s):  
Triticum Aestivum ◽  
Wheat Germ ◽  
Wheat Plant ◽  
Triticum Aestivum L ◽  
Immunohistochemical Localization ◽  
Plant Roots ◽  
Wheat Roots ◽  
Wheat Seedlings ◽  
Apoplastic Barrier ◽  
Protective Proteins

We studied the immunohistochemical localization of abscisic acid (ABA), wheat germ agglutinin (WGA) and dehydrins in the roots of wheat seedlings (Triticum aestivum L.) during 24-epibrassinolide-pretreatment (EB-pretreatment) and PEG-induced dehydration. It was found coimmunolocalization of ABA, WGA and dehydrins in the cells of central cylinder of basal part untreated and EB-pretreated roots of wheat seedlings under normal conditions and under osmotic stress. Such mutual localization ABA and protective proteins, WGA and dehydrins, indicates the possible effect of their distribution in the tissues of EB-pretreated wheat roots during dehydration on the apoplastic barrier functioning, which apparently contributes to decrease the water loss under dehydration. Perhaps, the significant localization of ABA and wheat lectin in the metaxylem region enhances EB-induced transport of ABA and WGA from roots to shoots under stress. It can be assumed that brassinosteroids can serve as intermediates in the realization of the protective effect of WGA and wheat dehydrins during water deficit.

scholarly journals Expression and function of the cdgD gene, encoding a CHASE–PAS-DGC-EAL domain protein, in Azospirillum brasilense

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
José Francisco Cruz-Pérez ◽  
Roxana Lara-Oueilhe ◽  
Cynthia Marcos-Jiménez ◽  
Ricardo Cuatlayotl-Olarte ◽  
María Luisa Xiqui-Vázquez ◽  
...  
Keyword(s):  
Azospirillum Brasilense ◽  
Type Strain ◽  
Wild Type Strain ◽  
Soil Conditions ◽  
Wild Type ◽  
Gene Encoding ◽  
Wheat Roots ◽  
Genes Encoding ◽  
In The Wild ◽  
Plant Growth Promoting

AbstractThe plant growth-promoting bacterium Azospirillum brasilense contains several genes encoding proteins involved in the biosynthesis and degradation of the second messenger cyclic-di-GMP, which may control key bacterial functions, such as biofilm formation and motility. Here, we analysed the function and expression of the cdgD gene, encoding a multidomain protein that includes GGDEF-EAL domains and CHASE and PAS domains. An insertional cdgD gene mutant was constructed, and analysis of biofilm and extracellular polymeric substance production, as well as the motility phenotype indicated that cdgD encoded a functional diguanylate protein. These results were correlated with a reduced overall cellular concentration of cyclic-di-GMP in the mutant over 48 h compared with that observed in the wild-type strain, which was recovered in the complemented strain. In addition, cdgD gene expression was measured in cells growing under planktonic or biofilm conditions, and differential expression was observed when KNO3 or NH4Cl was added to the minimal medium as a nitrogen source. The transcriptional fusion of the cdgD promoter with the gene encoding the autofluorescent mCherry protein indicated that the cdgD gene was expressed both under abiotic conditions and in association with wheat roots. Reduced colonization of wheat roots was observed for the mutant compared with the wild-type strain grown in the same soil conditions. The Azospirillum-plant association begins with the motility of the bacterium towards the plant rhizosphere followed by the adsorption and adherence of these bacteria to plant roots. Therefore, it is important to study the genes that contribute to this initial interaction of the bacterium with its host plant.

scholarly journals Enhancement of drought tolerance in Triticum aestivum L. seedlings using Azospirillum brasilense NO40 and Stenotrophomonas maltophilia B11

2021 ◽  
Vol 45 (1) ◽  
Author(s):  
Wedad A. Kasim ◽  
Mohamed E. H. Osman ◽  
Mohamed N. Omar ◽  
Samar Salama
Keyword(s):  
Triticum Aestivum ◽  
Drought Stress ◽  
Drought Tolerance ◽  
Azospirillum Brasilense ◽  
Stenotrophomonas Maltophilia ◽  
Protein Pattern ◽  
Triticum Aestivum L ◽  
Protein Patterns ◽  
Wheat Seedlings ◽  
Enhanced Production

Abstract Background The effectiveness of two PGPB; Azospirillum brasilense NO40 and Stenotrophomonas maltophilia B11 was investigated in enhancing the drought tolerance of wheat (Triticum aestivum L.) seedlings cultivar Gemiza9. The inoculated or uninoculated grains were sown in unsterilized sandy soil and watered normally untill the 8th day. Drought stress was initiated by completely withholding water for 7 days (until wilting). Samples were collected after 15 days from sowing to evaluate some growth criteria, damage and defense indicators and to analyze the roots’ protein pattern. Results The results showed that inoculating wheat seedlings with these strains significantly diminished the inhibitory effects of drought stress on the relative water content of roots, shoots and leaves; area of leaves; contents of pigments (chlorophyll a and b) and ascorbic acid; and on the protein patterns of roots. Moreover, the bacterial inoculation notably reduced the drought-induced damage indicated by lower leakage of electrolytes and less accumulation of Malondialdehyde and hydrogen peroxide, surprisingly with less enhanced production of proline and activities of catalase and peroxidase than their uninoculated counterparts. Under normal conditions, inoculating wheat plants with these PGPB resulted in significantly promoted growth and elevated contents of pigments and altered protein patterns of roots. Conclusion Overall, we can say that both Azospirillum brasilense NO40 and Stenotrophomonas maltophilia B11 were able to deactivate the growth inhibition in wheat seedlings to some extent, while maintaining a certain level of efficient protection against damage under drought stress.

An improved selection technique and medium for the isolation and enumeration of Azospirillum brasilense

1985 ◽  
Vol 31 (10) ◽  
pp. 947-952 ◽  
Author(s):  
Yoav Bashan ◽  
Hanna Levanony
Keyword(s):  
Azospirillum Brasilense ◽  
Sodium Deoxycholate ◽  
Selective Medium ◽  
Most Probable Number ◽  
Streptomycin Sulphate ◽  
Triphenyltetrazolium Chloride ◽  
Wheat Roots ◽  
Semisolid Medium ◽  
Probable Number ◽  
Selection Technique

An improved selection technique for isolation and enumeration of Azospirillum brasilense was developed. The technique is based on successive liquid enrichments in nitrogen-free semisolid medium supplemented with streptomycin, followed by the most probable number counting method and verification on a selective medium. The latter is based on Okon's nitrogen-free medium supplemented with cycloheximide (250 mg/L), streptomycin sulphate (200 mg/L), sodium deoxycholate (200 mg/L), 2,3,5-triphenyltetrazolium chloride (15 mg/L), and Congo red (1000 mg/L). This medium was found to be superior to other available diagnostic media. The technique was readily applied to detect and count A. brasilense Cd in inoculated wheat roots.

scholarly journals Two different modes of attachment of Azospirillum brasilense Sp7 to wheat roots

1991 ◽  
Vol 137 (9) ◽  
pp. 2241-2246 ◽  
Author(s):  
K. W. Michiels ◽  
C. L. Croes ◽  
J. Vanderleyden
Keyword(s):  
Azospirillum Brasilense ◽  
Wheat Roots ◽  
Azospirillum Brasilense Sp7

scholarly journals Plant Cell Wall Changes in Common Wheat Roots as a Result of Their Interaction with Beneficial Fungi of Trichoderma

Cells ◽  
2020 ◽  
Vol 9 (10) ◽  
pp. 2319
Author(s):  
Aneta Basińska-Barczak ◽  
Lidia Błaszczyk ◽  
Kinga Szentner
Keyword(s):  
Cell Wall ◽  
Common Wheat ◽  
Plant Cell ◽  
Plant Cell Wall ◽  
Arabinogalactan Protein ◽  
Plant Cell Walls ◽  
Wheat Roots ◽  
Wheat Seedlings ◽  
Trichoderma Species ◽  
Defense Strategies

Plant cell walls play an important role in shaping the defense strategies of plants. This research demonstrates the influence of two differentiators: the lifestyle and properties of the Trichoderma species on cell wall changes in common wheat seedlings. The methodologies used in this investigation include microscopy observations and immunodetection. In this study was shown that the plant cell wall was altered due to its interaction with Trichoderma. The accumulation of lignins and reorganization of pectin were observed. The immunocytochemistry indicated that low methyl-esterified pectins appeared in intercellular spaces. Moreover, it was found that the arabinogalactan protein epitope JIM14 can play a role in the interaction of wheat roots with both the tested Trichoderma strains. Nevertheless, we postulate that modifications, such as the appearance of lignins, rearrangement of low methyl-esterified pectins, and arabinogalactan proteins due to the interaction with Trichoderma show that tested strains can be potentially used in wheat seedlings protection to pathogens.

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