Indoleacetic acid production and plant growth promoting potential of bacterial endophytes isolated from rice (Oryza sativa L.) seeds (original) (raw)
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In this paper, we report the endophytic microbial diversity of cultivated and wild Oryza sativa plants including their functional traits related to multiple traits that promote plant growth and development. Around 255 bacteria were isolated out of which 70 isolates were selected for further studies based on their morphological differences. The isolates were characterized both at biochemical and at the molecular level by 16s rRNA gene sequencing. Based on 16S rRNA gene sequencing the isolates were categorized into three major phyla, viz, Firmicutes (57.1 %), Actinobacteria (20.0 %) and Proteobacteria (22.8 %). Firmicutes was the dominant group of bacteria of which the most abundant genus was Bacillus. The isolates were further screened in vitro for plant growth promoting activities which revealed a hitherto unreported endophytic bacterial isolate, Microbacteriaceae bacterium RS01 11 as the highest secretor of a phytohormone, IAA (28.39 ± 1.39 μg/ml) and GA (67.23 ± 1.83 μg/ml). Bacil...
In planta selection of plant growth promoting endophytic bacteria for rice (Oryza sativa L.)
Journal of soil science and plant nutrition, 2014
In this study, bacteria were isolated from the rhizosphere and inside the roots of canola (Brassica napus L.) plants grown in the field from northern Iran. Firstly, 150 strains (endophytic and rhizospheric isolates) isolated from canola were characterized for plant growth promoting (PGP) traits. Of them, one hundred isolates produced indole-3-acetic acid (IAA), whereas 17 isolates solubilized phosphate, 44 isolates produced siderophore, 34 produced 1-aminocyclopropane-1-carboxylate (ACC) deaminase and five produced hydrocyanic acid (HCN). All of the screened isolates with different growth promoting traits were separately inoculated as different mixtures on two rice cultivars under gnotobiotic conditions. A total of 22 endophytic isolates were re-isolated from two rice cultivars and characterized for Plant Growth Promoting (PGP) traits again. All 22 endophytic isolates produced IAA. Secondly, the colonization and growth promoting effects of the IAA producing endophytic strains were compared in inoculated rice plantlets as single-strain inoculants. All of the IAA producing strains were consistently more active in colonizing rice seedlings as compared with other isolates. Therefore, it seems that IAA production may be required for endophytic competence as compared to other PGP traits in rice seedlings. In addition, this study indicates that the selected bacterial isolates based on their IAA producing trait have the potential for PGP and more colonization of rice.
South African Journal of Botany, 2020
Bacterial endophytes live inside the plant tissues and known to play a crucial role in the functioning of host plants through influencing their physiology and development. In present study, a total of 32 bacterial endophytes were isolated from four plant tissues (root, stem, leaf and grain) of six rice varieties cultivated in central-eastern and northeastern states of India. Microbial composition varied among the plant tissues studied, they were predominant in the root and leaf tissues. Biochemical and molecular characterization identified these bacterial isolates belonging to phyla Proteobacteria and Firmicutes representing 5 genera. Out of 32 isolates, (19) 59.3% Gram's stain-positive, (17) 53.1% were able to produce indole acetic acid, (9) 28.1% siderophore development and (18) 56.2% phosphate solubilization activities indicating the plant growth-promoting (PGP) ability. The antagonistic activity of identified bacterial endophytes was determined against bacterial leaf blight disease-causing pathogen, Xanthomonas oryzae pv. oryzae (8 isolates) and soilborne fungal pathogens viz, Rhizoctonia solani (17 isolates), Fusarium verticillioides (15 isolates) and Sclerotium rolfsii (9 isolates) were exhibiting antagonistic activities against tested pathogens. Further, to confirm the probable role of lipopeptides in antagonism, PCR based detection of lipopeptide genes in the genome of bacterial endophytes showed the presence of antibacterial (surfactin) and antifungal (iturin D and bacillomycin D) genes in Bacillus subtilis (NIBSM_OsR10). This Bacillus subtilis isolate showed potential antibacterial activities against Xanthomonas oryzae pv. oryzae and strong antagonistic activities against fungal pathogens Rhizoctonia solani, Fusarium verticelloides and Sclerotium rolfsii. Potential isolates exhibiting antibacterial and antifungal activities in the present study may be used for the development of biocontrol formulations for controlling multiple biotic stresses.
The Potential Endophytic Bacteria Isolated from Rice (Oryza sativa) as Biofertilizer
Biosaintifika: Journal of Biology & Biology Education
Endophytic bacteria are beneficial microorganisms that interact with host plants without causing any interference or damage to plants. This research aimed to obtain endophytic bacteria isolated from the root tissue of rice plants (Oryza sativa L.) which have potential to produce IAA hormones,, identify the endophytic bacteria in morphologically and physiologically, and analysis of the selected isolate 16S rRNA genes. Based on the results of this research, there were six endophytic bacteria isolates obtained. They have high morphological diversity and differen ability producing IAA hormones. The highest concentration of IAA (425 ppm) was obtained isolates from EAP3. Isolate EAP3 also produce inhibit the growth of Xanthomonas oryzae with a 5.2 mm inhibition zone. Based on the biochemical test, EAP3 had 60% similarity with Enterobacter asburiae. Analysis of the 16S rRNA gene showed that EAP3 had the highest similarity with Enterobacter asburiae strain U4 by 99%. This research data i...
Production of Phytohormones by Endophytic Bacteria Isolated from Aerobic Rice
2016
Endophytic bacteria colonize the interior of the plant parts, without causing any harmful effect and promote plant growth. An investigation was carried out to isolate endophytic bacteria from aerobic rice varieties that have the potential to produce phytohormones like indole-3-acetic acid (IAA), gibberellins (GA) and cytokinin. Total of twenty four endophytic bacteria were isolates from rice tissues of the four varieties of aerobic rice. Eight endophytic bacteria designated as ARBR3, AM65R1, IR64L1, ARBS2, AM65S2, IR64R1 AND JERR2 were found to produce IAA in the range of 226.59-10.86 μg/ ml. GA was found to produce by six endophytic isolates from the root, shoot and leave of the four varieties of aerobic rice, these isolates are ARBR2, ARBR3, AM65R2, AM65L1, IR64R1, and IR64S2 in which the concentration ranges from 5.43-2.56. Only three isolates produced cytokinin where isolate JER produced highest concentration (5.42 μg/ml). This work revealed that some endophytic bacteria from ae...
Tropical Life Sciences Research
Indole-3-acetic acid (IAA) is one of the most physiologically active auxins produced by rhizobacteria and is potentially applied for agriculture. Two endophytic bacteria, VR2 and MG9, isolated from the root of Chrysopogon zizanioides (L.) collected at Cha-Am, and the leaf of Bruguiera cylindrica (L.) Blume collected from a mangrove forest at Ban Laem, Phetchaburi Province, Thailand, were taxonomic characterised based on their phenotypic characteristics and 16S rRNA gene analysis. Strain VR2 was closely related to Enterobacter hormaechei CIP 103441T (99.6% similarity), while strain MG9 was closely related to Bacillus aryabhattai B8W22T (99.9% similarity). Consequently, they were identified as Enterobacter hormaechei and Bacillus aryabhattai, respectively. The IAA production of VR2 and MG9 strains are determined and applied to rice seeds for their root and shoot germination. Strains VR2 and MG9 greatly produced a yield of IAA, 246.00 and 195.55 µg/mL in 1,000 µg/mL of L-tryptophan at ...
BMC microbiology, 2017
Rice (Oryza sativa L. ssp. indica) seeds as plant microbiome present both an opportunity and a challenge to colonizing bacterial community living in close association with plants. Nevertheless, the roles and activities of bacterial endophytes remain largely unexplored and insights into plant-microbe interaction are compounded by its complexity. In this study, putative functions or physiological properties associated with bacterial endophytic nature were assessed. Also, endophytic roles in plant growth and germination that may allow them to be selectively chosen by plants were also studied. The cultivable seed endophytes were dominated by Proteobacteria particularly class Gammaproteobacteria. Highly identical type strains were isolated from the seed endosphere regardless of the rice host's physiological tolerance to salinity. Among the type strains, Flavobacterium sp., Microbacterium sp. and Xanthomonas sp. were isolated from the salt-sensitive and salt-tolerant cultivars. PCA-Bi...
MethodsX, 2015
Plants select plant growth promoting rhizobacteria (PGPR) that are competitively fit to occupy compatible niches without causing pathological stress on them. However, when screening bacteria for plant growth promoting (PGP) agents, it is better to select bacteria for achieving the most promising isolates having suitable colonization and PGP traits. In most researches, it has been seen that following incubation, bacterial flora are taken at random from petri dishes for further study. However, this type of selection may remove some superior bacteria in terms of PGP traits and high colonization ability. Therefore, it is essential to study all the isolated bacteria in an economic way and select the best bacteria in terms of PGP traits and high colonization rate. A simple screening method to detect endophytic and rhizosphere bacteria, isolated from the plants in rotation with rice, for rice PGP agents based on a root colonization bioassay and a PGP trait is characterized.
Annals of Microbiology, 2011
Desert plants are able to survive under harsh environmental stresses inherent to arid and semiarid regions due to their association with bacterial endophytes. However, the identity, functions, and the factors that influence the association of bacterial endophytes with desert plants are poorly known. These bacterial endophytes can be used as an untapped resource to favor plant growth and development in agro-ecosystems of arid regions. The present study is therefore focused on the isolation and identification of bacterial endophytes from two native medicinal plants (Fagonia mollis Delile and Achillea fragrantissima (Forssk) Sch. Bip.) growing spontaneously in the arid region of the South Sinai (Egypt), and characterization of their plant growth promoting (PGP) traits. Thirteen putative bacterial endophytes were isolated from the leaves of both plant species and characterized for their plant growth promoting abilities using molecular and biochemical approaches, as well as greenhouse trials. Selected endophytic bacterial strains were applied to maize plants (Zea mays L. var. Single cross Pioneer 30K08) to further evaluate their PGP abilities under greenhouse conditions. Isolated bacterial strains have variable plant growth promoting activities. Among these activities, isolated bacterial endophytes have the efficacy of phosphate solubilizing with clear zones ranging from 7.6 ± 0.3 to 9.6 ± 0.3 mm. Additionally, the obtained bacterial endophytes increased the productivity of indole acetic acid (IAA) in broth media from 10 to 60 µg•mL −1 with increasing tryptophan concentration from 1 to 5 mg•mL −1. Bacillus and Brevibacillus strains were frequently isolated from the leaves of both plant species, and had significant positive effects on plant growth and shoot phosphorus (P) and nitrogen (N) contents. Results suggest that these endophytes are good candidates as plant growth promoting inoculants to help reduce chemical input in conventional agricultural practices and increase nutrient uptake and stress resilience in plant species.
We have isolated 576 endophytic bacteria from the leaves, stems, and roots of 10 rice cultivars and identified 12 of them as diazotrophic bacteria using a specific primer set of nif gene. Through 16S rDNA sequence analysis, nifH genes were confirmed in the two species of Penibacillus, three species of Microbacterium, three Bacillus species, and four species of Klebsiella. Rice seeds treated with these plant growth-promoting bacteria (PGPB) showed improved plant growth, increased height and dry weight and antagonistic effects against fungal pathogens. In addition, auxin and siderophore producing ability, and phosphate solubilizing activity were studied for the possible mechanisms of plant growth promotion. Among 12 isolates tested, 10 strains have shown higher auxin producing activity, 6 isolates were confirmed as strains with high siderophore producing activity while 4 isolates turned out to have high phosphate-solubilizing activity. These results strongly suggest that the endophytic diazotrophic bacteria characterized in this study could be successfully used to promote plant growth and inducing fungal resistance in plants.