Evaluation of plant-growth promoting properties of Gluconacetobacter diazotrophicus and Gluconacetobacter sacchari isolated from sugarcane and tomato in West Central region of Colombia (original) (raw)
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IOP Conf. Series: Earth and Environmental Science, 2021
The present review was focused on the isolation and nitrogen-fixing efficiency of Gluconacetobacter diazotrophicus associated with sugarcane crop. Gluconacetobacter diazotrophicus has a long-standing partnership with the bacterium Escherichia coli as an entophyte, which can efficiently fix atmospheric nitrogen. It plays a significant role and occurs in most sugarcane growing countries. It has been found to reside in the sugar cane root, stem, buds and leaves. Biological nitrogen fixation based farming systems would enhance agricultural production in the long term in both economically viable and socially acceptable way. This process not only replaces the most expensive fertilizer but also reduces considerably groundwater pollution with nitrates because biological nitrogen fixation was self-regulated. Convincing evidence has pointed out that biological nitrogen fixation requiring a relatively simple and low-cost technology, easy to execute and largely renewable sources of energy has a tremendous role to play in the immediate further of agriculture, especially in the developing and underdeveloped countries.
Isolation and Biochemical Characterization of Endophytic Bacterium Gluconacetobacter diazotrophocus from Native Sugarcane Cultivar of middle Gangetic Plains of India, 2024
The study focused on the isolation and characterization of Gluconacetobacter diazotrophocus, an endophytic bacterium obtained from various parts of a native sugarcane cultivar in India's middle Gangetic plains. Using conventional culturing methods, isolated and screened 115 isolates, ultimately selecting 15 highly efficient isolates based on their production of growth-promoting hormones. Among these, GdS08S, isolated from sugarcane cultivar CoP-9301, exhibited the highest nitrogen-fixing ability, with 153μg of N/mg of carbon used. Isolate GdS15S, from sugarcane cultivar Co-0238, produced the highest concentration of gibberellic acid (8.19μg/25ml). Additionally, GdS07R displayed notable phosphorus and zinc solubilization zones, measuring 4.22 cm and 4.52 cm, respectively. Gluconacetobacter diazotrophocus, residing within sugarcane tissues, plays a pivotal role in promoting rooting, cell elongation, and overall sugarcane growth through the biosynthesis of indole-3-acetic acid (IAA) and gibberellic acid (GA). Furthermore, it actively fixes atmospheric nitrogen, offering a significant nitrogen supply to the growing crops. This research underscores the significance of G. diazotrophocus as a potential biofertilizer for native sugarcane cultivars in the middle Gangetic plains of India, contributing to sustainable agriculture practices.
Plant and Soil
To identify active diazotrophs in sugarcane, 16S rRNA and nifH transcript analyses were applied. This should help to better understand the basis of the biological nitrogen fixation (BNF) activity of a high nitrogen fixing sugarcane variety. A field experiment using the sugarcane variety RB 867515 was conducted in Seropédica, RJ, Brazil, receiving the following treatments: unfertilised and fertilised controls without inoculation, unfertilised with inoculation. The five-strain mixture developed by EMBRAPA-CNPAB was used as inoculum. Root and leaf sheath samples were harvested in the third year of cultivation to analyse the 16S rRNA and nifH transcript diversity. In addition to nifH expression from Gluconacetobacter spp. and Burkholderia spp., a wide diversity of nifH sequences from previously uncharacterised Ideonella/Herbaspirillum related phylotypes in sugarcane shoots as well as Bradyrhizobium sp. and Rhizobium sp. in roots was found. These results were confirmed using 16S cDNA analysis. From the inoculated bacteria, only nifH transcripts from G. diazotrophicus and B. tropica were detected in leaf sheaths and roots. Known as well as yet uncultivated diazotrophs were found active in sugarcane roots and stems using molecular analyses. Two strains of the inoculum mix were identified at the late summer harvest.
Plant and Soil, 2012
Background and aims Rhizospheric, epiphytic and endophytic bacteria are associated with several nonlegumes, colonizing their surface and inner tissues. Many of these bacteria are beneficial to their hosts, phomonas, Xanthomonas, Acinetobacter, Rhanella, Enterobacter, Pantoea, Shinella, Agrobacterium and Achromobacter. Additionally, some PGP features were studied in 35 selected isolates. The data obtained in this study represent the initial steps in a program Plant Soil (2012) 356:35-49 aimed at determining the mechanisms of PGP of nonlegume crops in Uruguay (such as sugarcane) with potentially beneficial plant-associated bacteria. Keywords Saccharum officinarum . Endophytes . Diazotrophs . PGPR . 15 N-isotope dilution Abbreviations BNF Biological nitrogen fixation IAA indole-3-acetic acid PGPE plant growth promoting endophytes % 15 N a.e atom % 15 N excess 15 N % Ndfa percent nitrogen derived from air
Microbial Ecology, 2008
Gluconacetobacter diazotrophicus has a long-standing history of bacterial-plant interrelationship as a symbiotic endophyte capable of fixing atmospheric nitrogen. In low nitrogen fertilized sugarcane fields it plays a significant role and its occurrence was realised in most of the sugarcane growing countries. In this mini review, the association of G. diazotrophicus with sugarcane, other crop plants and with various hosts is discussed. The factors affecting survival in the rhizosphere and the putative soil mode of transmission are emphasized. In addition, other N 2-fixing Acetobacteraceae members, including Gluconacetobacter azotocaptans, Gluconacetobacter johannae and Swaminathania salitolerans, occurring in coffee, corn and rice plants are also covered. Lastly, the plant-growth-promoting traits identified in this group of bacteria, including N 2 fixation, phytohormone synthesis, P and Zn solubilization and biocontrol, are analysed. 140 V.S. SARAVANAN ET AL.: ECOLOGICAL OCCURRENCE OF G.
Microbiological Research, 2004
Endophytic bacteria were isolated from the tissues of surface sterilized roots, stems, and leaves of fifty different crop plants. Phenotypic, biochemical tests and speciesspecific PCR assay permitted identification of four isolates of Gluconacetobacter diazotrophicus from root tissues of carrot (Daucus carota L.), raddish (Raphanus sativus L.), beetroot (Beta vulgaris L.) and coffee (Coffea arabica L.). Further the plant growth promoting traits such as nitrogenase activity, production of phytohormone indole acetic acid (IAA), phosphorus and zinc solubilization were assessed. Significant nitrogenase activity was recorded among the isolates and all the isolates produced IAA in the presence of tryptophan. Though all the four isolates efficiently solubilized phosphorus, the zinc solubilizing ability differed among the isolates.
The numbers of culturable diazotrophic endophytic bacteria (CDEB) from roots, stems and leaves of sugarcane submitted to organic, inorganic or no fertilization were compared. In order to determine the size of the N2 fixing populations, the Most Probable Number technique (MPN) was used. The quantification of diazotrophic bacteria by using the acetylene reduction assay (ARA) was more accurate than observing the bacterial growth in the vials; to confirm N2 fixing capability, the detection of gene nifH was performed on a sample of 105 isolated bacteria. The production of extracellular enzymes involved in the penetration of the plants by the bacteria was also studied. The results showed that organic fertilization enhances the number of CDEB when compared with conventional fertilization used throughout the growing season. The maximum number of bacteria was detected in the roots. Roots and stems presented the greatest number of CDEB in the middle of the cropping season and in leaves numbers varied according to the treatment. Using two pairs of primers and two different methods, the nifH gene was found in 104 of the 105 tested isolates. Larger amounts of pectinase were released by isolates from sugarcane treated with conventional fertilizers (66%), whereas larger amounts of cellulase were released by strains isolated from sugarcane treated with organic fertilizers (80%).
Twelve bacterial strains were isolated from root and rhizosphere samples collected from different sugarcane growing areas. Of these strains, ten strains were identified as Pseudomonas and two as Azotobacter on the basis of colony-and cell-morphology. Among isolates the presence of nifH gene was detected only in two Azotobacter strains (Azoto1 and Azoto2). Acetylene reduction activity of the strains Azoto1 and Azoto2 determined in N-free medium was 1966 and 4210 nmole C H /vial/24h, respectively. All isolates showed IAA 2 4 production in growth medium containing tryptophane as a precursor. Maximum IAA production (4.49mg/L) was detected in isolate A17 where as IAA production in strains A4 and A11 was also significant. Values for IAA production by nitrogen fixing isolates Azoto1 and Azoto2 were comparatively low (0.2 and 0.1mg/L respectively). For rapid screening of bacterial isolates from sugarcane, heterologous plant host (sorghum) was used as a test plant. Most of the strains showed beneficial effects on root length, root area and plant dry weight which were comparable to those observed in treatments where confirmed PGPR were used as positive control. Beneficial effects of inoculation on sugarcane grown in pots were also observed.
Microbiological Research, 2006
Colonization of micropropagated sugarcane plants by Gluconacetobacter diazotrophicus and Herbaspirillum sp. was confirmed by a dot-immunoblot assay. In all, a 45day short-term and 180-day long-term experiments conducted on micropropagated sugarcane plants of Co 86032, a sugar rich popular variety in South India, indicated the usefulness of these diazotrophs as plant growth promoting bacteria. Coinoculation of these two bacteria enhanced the biomass considerably under Nlimited condition in the short duration experiment. In the long-term experiment, the establishment of inoculated Herbaspirillum sp. remained stable with the age of the crop up to 180 days, while there was a reduction in population of G. diazotrophicus for the same period. The total bio-mass and leaf N were higher in plants inoculated with G. diazotrophicus and Herbaspirillum sp. without N fertilization and also in plants with 50% of the recommended N (140 kg ha À1 ) than the plants fertilized with recommended dose of inorganic N (280 kg ha À1 ). This experiment showed that inoculation with these bacteria in sugarcane variety Co 86032 could mitigate fertilizer N application considerably in sugarcane cultivation.
Revista Argentina de Microbiología, 2015
It has been established that a decrease in the population of Gluconacetobacter diazotrophicus associated with sugarcane occurs after nitrogen fertilization. This fact could be due to a direct influence of NH 4 NO 3 on bacterial cells or to changes in plant physiology after fertilizer addition, affecting bacterial establishment. In this work, we observed that survival of G. diazotrophicus was directly influenced when 44.8 mM of NH 4 NO 3 (640 mg N/plant) was used for in vitro experiments. Furthermore, micropropagated sugarcane plantlets were inoculated with G. diazotrophicus and used for split root experiments, in which both ends of the system were fertilized with a basal level of NH 4 NO 3 (0.35 mM; 10 mg N/plant). Twenty days post inoculation (dpi) one half of the plants were fertilized with a high dose of NH 4 NO 3 (6.3 mM; 180 mg N/plant) on one end of the system. This nitrogen level was lower than that directly affecting G. diazotrophicus cells; however, it caused a decrease in the bacterial population in comparison with control plants fertilized with basal nitrogen levels. The decrease in the population of G. diazotrophicus was higher in pots fertilized with a basal nitrogen level when compared with the corresponding end supplied with high levels of NH 4 NO 3 (100 dpi; 80 days post fertilization) of the same plant system. These observations suggest that the high nitrogen level added to the plants induce systemic physiological changes that affect the establishment of G. diazotrophicus.