scholarly journals The Study on the Cultivable Microbiome of the Aquatic Fern Azolla Filiculoides L. as New Source of Beneficial Microorganisms

2019 ◽  
Vol 9 (10) ◽  
pp. 2143 ◽  
Author(s):  
Artur Banach ◽  
Agnieszka Kuźniar ◽  
Radosław Mencfel ◽  
Agnieszka Wolińska

The aim of the study was to determine the still not completely described microbiome associated with the aquatic fern Azolla filiculoides. During the experiment, 58 microbial isolates (43 epiphytes and 15 endophytes) with different morphologies were obtained. We successfully identified 85% of microorganisms and assigned them to 9 bacterial genera: Achromobacter, Bacillus, Microbacterium, Delftia, Agrobacterium, and Alcaligenes (epiphytes) as well as Bacillus, Staphylococcus, Micrococcus, and Acinetobacter (endophytes). We also studied an A. filiculoides cyanobiont originally classified as Anabaena azollae; however, the analysis of its morphological traits suggests that this should be renamed as Trichormus azollae. Finally, the potential of the representatives of the identified microbial genera to synthesize plant growth-promoting substances such as indole-3-acetic acid (IAA), cellulase and protease enzymes, siderophores and phosphorus (P) and their potential of utilization thereof were checked. Delftia sp. AzoEpi7 was the only one from all the identified genera exhibiting the ability to synthesize all the studied growth promoters; thus, it was recommended as the most beneficial bacteria in the studied microbiome. The other three potentially advantageous isolates (Micrococcus sp. AzoEndo14, Agrobacterium sp. AzoEpi25 and Bacillus sp. AzoEndo3) displayed 5 parameters: IAA (excluding Bacillus sp. AzoEndo3), cellulase, protease, siderophores (excluding Micrococcus sp. AzoEndo14), as well as mineralization and solubilization of P (excluding Agrobacterium sp. AzoEpi25).

2017 ◽  
Vol 39 (2) ◽  
Author(s):  
GLEIKA LARISSE OLIVEIRA DORASIO DE SOUZA ◽  
DEIVISSON FERREIRA DA SILVA ◽  
SILVIA NIETSCHE ◽  
ADELICA APARECIDA XAVIER ◽  
MARLON CRISTIAN TOLEDO PEREIRA

ABSTRACT The use of bio-fertilizers and microbial inoculants that promote plant growth and increased yield has been accepted as an alternative to reduce the use of chemical fertilizers. The objective of the present study was to evaluate the effect of plant growth promoting bacteria inoculation on growth and quality of micropropagated banana seedlings ‘Prata Anã’. The experimental design was completely randomized, with four replications and the treatments consisted of 24 isolates of endophytic bacteria. The isolates EB-50 (Bacillus sp.) and EB-133 (Bacillus amyloliquefaciens) characterized as diazotrophic, the EB-51 (Bacillus pumilus) indicate for inorganic phosphate solubilization and EB-55(Bacillus subtilis) and EB-40 (Bacillus sp.) indole-3-acetic acid producers have provided significant increases for length, pseudostem diameter, fresh masses and dry masses in ‘Prata Anã’ micropropagated banana seedlings.


2021 ◽  
Vol 49 (2) ◽  
pp. 12294
Author(s):  
Maria T. SALAZAR-RAMÍREZ ◽  
Jorge SÁENZ-MATA ◽  
Pablo PRECIADO-RANGEL ◽  
Manuel FORTIS-HERNÁNDEZ ◽  
Edgar O. RUEDA-PUENTE ◽  
...  

In the communities of Sierra Mojada and Viesca, Coahuila, Mexico of Coahuila desert, two rhizosphere samplings of candelilla (Euphorbia antisyphilitica Zucc) were collected to isolate, characterize, and identifying plant growth-promoting rhizobacteria (PGPR); 165 rhizobacteria were tested in vitro with Arabidopsis thaliana seedlings to evaluate their potential as plant growth promoters, and obtaining 21 strains with best results in the variables of the number of secondary roots and fresh weight concerning the uninoculated control. Their salinity tolerance was evaluated at concentrations from 0.85 M, 1.7 M and 2.55 M of NaCl. Biochemical tests were accomplishing such as siderophores production, phosphates solubilization, production of Indole-3-acetic acid (IAA), and the activity of the ACC deaminase enzyme. The results obtained from 21 strains selected, high activities were obtained in organic substances like a siderophores since they developed a translucent orange halo around their growth; four rhizobacteria developed a clear halo around the bacterial growth with a thickness between 1.487 mm ± 0.667 mm and 5.267 mm ± 0.704 mm in phosphates solubilization; in the production of Indole-3-acetic acid (IAA), the bacterial strains showed the presence of this phytohormone, with values ​​from 4.444 μg mL-1 to 19.286 μg mL-1; and according to the activity of the ACC deaminase enzyme, values ​​from 0.424 to 1.306 µmol α-KB/h/mg Pr were showed. 16S rRNA sequencing was carried out and genus identified were Bacillus, Staphylococcus, Acinetobacter, Cronobacter and Siccibacter. The results obtained show the potential of the isolated rhizobacteria as growth promoters and the increase in the biomass of the Arabidopsis thaliana seedlings is evident. This is a first indication to proceed to carry out tests in different phenological stages in crops of agricultural importance.


Author(s):  
J. Monk ◽  
E. Gerard ◽  
S. Young ◽  
K. Widdup ◽  
M. O'Callaghan

Tall fescue (Festuca arundinacea) is a useful alternative to ryegrass in New Zealand pasture but it is slow to establish. Naturally occurring beneficial bacteria in the rhizosphere can improve plant growth and health through a variety of direct and indirect mechanisms. Keywords: rhizosphere, endorhiza, auxin, siderophore, P-solubilisation


2016 ◽  
Vol 83 (1) ◽  
Author(s):  
Raúl Donoso ◽  
Pablo Leiva-Novoa ◽  
Ana Zúñiga ◽  
Tania Timmermann ◽  
Gonzalo Recabarren-Gajardo ◽  
...  

ABSTRACT Several bacteria use the plant hormone indole-3-acetic acid (IAA) as a sole carbon and energy source. A cluster of genes (named iac) encoding IAA degradation has been reported in Pseudomonas putida 1290, but the functions of these genes are not completely understood. The plant-growth-promoting rhizobacterium Paraburkholderia phytofirmans PsJN harbors iac gene homologues in its genome, but with a different gene organization and context than those of P. putida 1290. The iac gene functions enable P. phytofirmans to use IAA as a sole carbon and energy source. Employing a heterologous expression system approach, P. phytofirmans iac genes with previously undescribed functions were associated with specific biochemical steps. In addition, two uncharacterized genes, previously unreported in P. putida and found to be related to major facilitator and tautomerase superfamilies, are involved in removal of an IAA metabolite called dioxindole-3-acetate. Similar to the case in strain 1290, IAA degradation proceeds through catechol as intermediate, which is subsequently degraded by ortho-ring cleavage. A putative two-component regulatory system and a LysR-type regulator, which apparently respond to IAA and dioxindole-3-acetate, respectively, are involved in iac gene regulation in P. phytofirmans. These results provide new insights about unknown gene functions and complex regulatory mechanisms in IAA bacterial catabolism. IMPORTANCE This study describes indole-3-acetic acid (auxin phytohormone) degradation in the well-known betaproteobacterium P. phytofirmans PsJN and comprises a complete description of genes, some of them with previously unreported functions, and the general basis of their gene regulation. This work contributes to the understanding of how beneficial bacteria interact with plants, helping them to grow and/or to resist environmental stresses, through a complex set of molecular signals, in this case through degradation of a highly relevant plant hormone.


2020 ◽  
Vol 33 (7) ◽  
pp. 876-879
Author(s):  
Can Chen ◽  
Zonghao Yue ◽  
Cuiwei Chu ◽  
Keshi Ma ◽  
Lili Li ◽  
...  

Bacillus sp. strain WR11 isolated from the root of wheat (Triticum aestivum L.) possesses abiotic stress alleviating properties and produces several types of enzymes. However, its genomic information is lacking. The study described the complete genome sequence of the bacterium. The size of the genome was 4 202 080 base pairs that consisted of 4 405 genes in total. The G+C content of the circular genome was 43.53% and there were 4 170 coding genes, 114 pseudo genes, 30 ribosome RNAs, 86 tRNAs, and 5 ncRNAs, based on the Prokaryotic Genome Annotation Pipeline (PGAP). Many genes were related to the stress-alleviating properties and 124 genes existed in the CAZy database. The complete genome data of strain WR11 will provide valuable resources for genetic dissection of its plant growth-promoting function and symbiotic interaction with plant.


Horticulturae ◽  
2020 ◽  
Vol 6 (4) ◽  
pp. 81
Author(s):  
Ahsanul Salehin ◽  
Md Hafizur Rahman Hafiz ◽  
Shohei Hayashi ◽  
Fumihiko Adachi ◽  
Kazuhito Itoh

Sweet potato (Ipomoea batatas L.) grows well even in infertile and nitrogen-limited fields, and endophytic bacterial communities have been proposed to be responsible for this ability. Plant-growth-promoting bacteria are considered eco-friendly and are used in agriculture, but their application can interact with endophytic communities in many ways. In this study, a commercial biofertilizer, OYK, consisting of a Bacillus sp., was applied to two cultivars of sweet potato, and the effects on indigenous endophytic bacterial communities in field conditions were examined. A total of 101 bacteria belonging to 25 genera in 9 classes were isolated. Although the inoculated OYK was not detected and significant plant-growth-promoting effects were not observed, the inoculation changed the endophytic bacterial composition, and the changes differed between the cultivars, as follows: Novosphingobium in α-Proteobacteria was dominant; it remained dominant in Beniharuka after the inoculation of OYK, while it disappeared in Beniazuma, with an increase in Sphingomonas and Sphingobium in α-Proteobacteria as well as Chryseobacterium and Acinetobacter in Flavobacteria. The behavior of Bacilli and Actinobacteria also differed between the cultivars. The Shannon diversity index (H) increased after inoculation in all conditions, and the values were similar between the cultivars. Competition of the inoculant with indigenous rhizobacteria and endophytes may determine the fates of the inoculant and the endophytic community.


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