scholarly journals In-Vitro Plant Growth Promotion of Rhizobium Strains Isolated from Lentil Root Nodules under Abiotic Stresses

Agronomy ◽  
2020 ◽  
Vol 10 (7) ◽  
pp. 1006
Author(s):  
Badreddine Sijilmassi ◽  
Abdelkarim Filali-Maltouf ◽  
Sara Fahde ◽  
Youness Ennahli ◽  
Said Boughribil ◽  
...  

Plant growth-promoting rhizobia are known to improve crop performance by multiple mechanisms. However, the interaction between host plants and Rhizobium strains is highly influenced by growing conditions, e.g., heat, cold, drought, soil salinity, nutrient scarcity, etc. The present study was undertaken to assess the use of Rhizobium as plant growth promoters under abiotic stress conditions. Fifteen Rhizobium strains isolated from lentil root nodules were tested for phosphate solubilization activity (PSA) and phytohormones production under salt and drought conditions. The results showed that 15 Rhizobium strains were significant phosphate solubilizers, and indole acedic acid (IAA) and gibberellic acid (GA3) producers based on least significant difference (LSD) analysis (p ≤ 0.05). The highest rate of PSA was attributed to three strains namely, 1145N5, 1159N11, and 1159N32 with a range of 144.6 to 205.6 P2O5 (µg/mL). The highest IAA production was recorded in the strain 686N5 with 57.68 ± 4.25 µg/mL as compared to 50.8667 ± 1.41 µg/mL and 37.32 ± 12.59 µg/mL for Rhizobium tropici CIAT 899 and Azospirillum brasilense DSM-1690, respectively. Strain 318N2111 produced 329.24 ± 7.84 µg/mL of GA3 as against 259.84 ± 25.55 µg/mL for A. brasilense DSM-1690. R. tropici CIAT 899 showed tolerance to salt (5% NaCl) and drought (ψ = −2.6 MPa) stress, whereas strain 686N5 showed an extremely high level of salt-tolerance (5% NaCl) and moderate level of drought tolerance (ψ = −0.75 MPa). These results indicate different pathways for drought and salt tolerance mechanisms. The assessment of plant growth promoting (PGP) activities of Rhizobium showed differences between bacterial viability and bacterial PGP activity in terms of abiotic stress tolerance where bacterial PGP activity is interrupted before reaching the bacterial tolerance threshold. These results integrate a new concept of PGPR screening based on PGP activity under abiotic stress.

2007 ◽  
Vol 47 (8) ◽  
pp. 1008 ◽  
Author(s):  
Babur Saeed Mirza ◽  
M. Sajjad Mirza ◽  
Asghari Bano ◽  
Kauser A. Malik

The aim of the present study was to isolate plant-beneficial bacteria (both Rhizobium and plant growth promoting rhizobacteria) from roots and nodules of chickpea (Cicer arietinum L.) and to study the effect of coinoculations on growth of two cultivars of chickpea. Four Rhizobium strains were obtained from roots and four from the nodules of field-grown chickpea cv. Parbat and identified on the basis of morphological characteristics, and biochemical and infectivity tests on the host seedlings. Only one type of nitrogen and carbon source utilisation pattern and DNA banding pattern of random amplified polymorphic DNA was observed in all isolates (Rn1, Rn2, Rn3, Rn4) from nodules, while two types of such patterns were detected among the isolates from roots. The isolate Rr1 from roots also exhibited a pattern identical to those of the isolates from nodules, whereas the remaining three isolates (Rr2, Rr3 and Rr4) from roots showed a different pattern. Two strains of plant growth-promoting rhizobacteria belonging to genus Enterobacter were also isolated from chickpea roots. All the Rhizobium strains and Enterobacter strains produced the plant growth hormones indole acetic acid and gibberellic acid in the growth medium. Effects of the bacterial isolates as single- or double-strain inocula were studied on two chickpea cultivars (NIFA 88 and Parbat) grown in sterilised soil. In cultivar NIFA 88, coinoculation of Rhizobium strain Rn1 with Enterobacter strain B resulted in maximum increase in plant biomass and nodulation, as compared with the control treatment (non-inoculated as well as inoculated with Rhizobium strain Rn1 only), whereas the combination of Rhizobium Rn1 with Enterobacter A was more efficient in growth promotion of chickpea cv. Parbat. In non-sterilised soil, the same combinations of the Rhizobium strain Rn1 with Enterobacter strains A and B were found to be the most effective inoculants for cvv. Parbat and NIFA 88, respectively. However, some negative effects on plant growth were also noted in cv. Parbat coinoculated with Rhizobium strain Rr2 and Enterobacter strain B.


2019 ◽  
Vol 17 (3) ◽  
pp. 344-348
Author(s):  
FAA Zakry ◽  
P. Ammal ◽  
M. Malahubban ◽  
A. R. Faridah ◽  
A.H.M. Umar

A total of 30 bacterial isolates were isolated from soil, rhizoplane, and internal tissue of oil palm roots. The isolates were qualitatively tested for their potential to fix N2, solubilize inorganic P and K, and produce phytohormone indole-3-acetic acid. Of the 30 isolates, six isolates were able to exhibit multiple beneficial traits. All six isolates were then identified based on fatty acid methyl esters profile as Escherichia coli strain EX2, Serratia sp. strain EN1, Pantoea ananatis strain EN3, Bacillus sp. strain EN5, Pantoea ananatis strain EN8 and Pantoea sp. strain EN9. Subsequently, all shortlisted isolates were evaluated for plant growth-promoting potential by using shallot as a test plant. The plant test showed no significant difference (p>0.05) between inoculated and uninoculated plants except for Pantoea sp. strain EN9 inoculation which increased significantly (p<0.05) total root length over uninoculated control. Host specificity and IAA capacity of the isolates may be among the important factors affecting their effectiveness in plant growth promotion. J Bangladesh Agril Univ 17(3): 344–348, 2019


2016 ◽  
Vol 6 ◽  
Author(s):  
Fatin Syafikah Ismail ◽  
Masnindah Malahubban ◽  
Mohammad Hailmi Sajili ◽  
Zakry Fitri Ab. Aziz

<strong>The present study was conducted to isolate and characterize endophytic bacteria isolated from root nodules of <em>Acacia mangium</em> Willd and subsequently tested for plant growth promotion. A total of five bacterial isolates were successfully isolated and subjected to morphological and biochemical examination. The present study found that all isolates had almost similar morphologically but differed in growth rate. All isolates were negative on N-free and IAA tests, though positive on P solubilisation test. The present study demonstrated that the inoculation with isolate FSI3 had significantly improved (p&lt;0.05) root and shoot dry weight of winged bean seedlings as compared to uninoculated control. However, the inoculation did not significantly alter (p&gt;0.05) root and shoot length of winged bean seedlings. The present study suggests that the stimulatory effect by isolate FSI3 may be associated with P-solubilizing ability. A further test on isolate FSI3 is considered essential in future to uncover the several other possible plant growth-promoting mechanisms. </strong>


2020 ◽  
Vol 37 (1) ◽  
pp. 21-37
Author(s):  
P.O. Akintokun ◽  
E. Ezaka ◽  
A.K. Akintokun ◽  
O.A. Oyedele

The use of Rhizobacteria as biofertilizer is on the increase due to the ability of some of the bacteria to solubilize some insoluble essential nutrients in the soil and produce phytohormones necessary for plant growth. The effectiveness of two plant growth promoting rhizobacteria (Bacillus cereus and Pseudomonas aeruginosa) in plant growth promotion at different concentrations of glyphosate were evaluated. Some agronomic parameters such as plant height, size of girth, number of leaves on the screen house and field were measured and recorded. The results of the effects of P. aeruginosa on the height of maize at different concentrations showed that the plants inoculated with the isolates and planted on the soil without glyphosate (control) recorded the highest height on the 2nd (34.9 cm), 4th (52.45 cm), 6th (61.17 cm) and 8th (66.25 cm) weeks after planting, when compared to those planted on the soil spiked with different concentrations of glyphosate. The effects of the isolates on the size of girth of maize on the soil spiked with different concentrations of glyphosate showed the highest girth size on the soil inoculated with P. aeruginosa eight weeks after planting (8 WAP) with a girth size of 2.0cm and least at 14.4 mg/ml of glyphosate with a girth size of 1.2 cm at 8 weeks after planting. Similar trend was observed on the soil inoculated with B. cereus (without glyphosate) with the highest girth in the 2nd and 4th WAP (1.02 and 1.42 cm, respectively). The results of our field studies showed no significant difference (P≤0.05) in the height and number of leaves of the maize at different treatments and time (weeks after planting). Similar trend was observed i n the yield of maize. This study has shown that these isolates can be useful as biofertilizers especially in the absence or at low concentration of glyphosate. Keywords: Rhizobacteria, maize, Inoculants, Plant-growth-promotion.


2017 ◽  
Vol 6 (3) ◽  
Author(s):  
Sandhya Vardharajula ◽  
Ali SkZ ◽  
Sai Shiva Krishna Prasad Vurukonda ◽  
Manjari Shrivastava

Diversity ◽  
2021 ◽  
Vol 13 (1) ◽  
pp. 24
Author(s):  
Ling Min Jiang ◽  
Yong Jae Lee ◽  
Ho Le Han ◽  
Myoung Hui Lee ◽  
Jae Cheol Jeong ◽  
...  

Jejubacter calystegiae KSNA2T, a moderately halophilic, endophytic bacterium isolated from beach morning glory (Calystegia soldanella), was determined to be a novel species in a new genus in the family Enterobacteriaceae. To gain insights into the genetic basis of the salinity stress response of strain KSNA2T, we sequenced its genome using two complementary sequencing platforms (Illumina HiSeq and PacBio RSII). The genome contains a repertoire of metabolic pathways, such as those for nitrogen, phosphorus, and some amino acid metabolism pathways. Functional annotation of the KSNA2T genome revealed several genes involved in salt tolerance pathways, such as those encoding sodium transporters, potassium transporters, and osmoprotectant enzymes. Plant growth-promoting bacteria-based experiments indicated that strain KSNA2T promotes the germination of vegetable seeds in saline conditions. Overall, the genetic and biological analyses of strain KSNA2T provide valuable insights into bacteria-mediated salt tolerance in agriculture.


2019 ◽  
Vol 201 (9) ◽  
pp. 1295-1306 ◽  
Author(s):  
Sahar T. M. Tolba ◽  
Mohamed Ibrahim ◽  
Essam A. M. Amer ◽  
Doaa A. M. Ahmed

2021 ◽  
Vol 11 (5) ◽  
pp. 2233
Author(s):  
Maria J. Ferreira ◽  
Angela Cunha ◽  
Sandro Figueiredo ◽  
Pedro Faustino ◽  
Carla Patinha ◽  
...  

Root−associated microbial communities play important roles in the process of adaptation of plant hosts to environment stressors, and in this perspective, the microbiome of halophytes represents a valuable model for understanding the contribution of microorganisms to plant tolerance to salt. Although considered as the most promising halophyte candidate to crop cultivation, Salicornia ramosissima is one of the least-studied species in terms of microbiome composition and the effect of sediment properties on the diversity of plant-growth promoting bacteria associated with the roots. In this work, we aimed at isolating and characterizing halotolerant bacteria associated with the rhizosphere and root tissues of S. ramosissima, envisaging their application in saline agriculture. Endophytic and rhizosphere bacteria were isolated from wild and crop cultivated plants, growing in different estuarine conditions. Isolates were identified based on 16S rRNA sequences and screened for plant-growth promotion traits. The subsets of isolates from different sampling sites were very different in terms of composition but consistent in terms of the plant-growth promoting traits represented. Bacillus was the most represented genus and expressed the wider range of extracellular enzymatic activities. Halotolerant strains of Salinicola, Pseudomonas, Oceanobacillus, Halomonas, Providencia, Bacillus, Psychrobacter and Brevibacterium also exhibited several plant-growth promotion traits (e.g., 3-indole acetic acid (IAA), 1-aminocyclopropane-1-carboxylic acid (ACC) deaminase, siderophores, phosphate solubilization). Considering the taxonomic diversity and the plant-growth promotion potential of the isolates, the collection represents a valuable resource that can be used to optimize the crop cultivation of Salicornia under different environmental conditions and for the attenuation of salt stress in non-halophytes, considering the global threat of arable soil salinization.


Agronomy ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 888
Author(s):  
Giorgia Novello ◽  
Patrizia Cesaro ◽  
Elisa Bona ◽  
Nadia Massa ◽  
Fabio Gosetti ◽  
...  

The reduction of chemical inputs due to fertilizer and pesticide applications is a target shared both by farmers and consumers in order to minimize the side effects for human and environmental health. Among the possible strategies, the use of biostimulants has become increasingly important as demonstrated by the fast growth of their global market and by the increased rate of registration of new products. In this work, we assessed the effects of five bacterial strains (Pseudomonas fluorescens Pf4, P. putida S1Pf1, P. protegens Pf7, P. migulae 8R6, and Pseudomonas sp. 5Vm1K), which were chosen according to their previously reported plant growth promotion traits and their positive effects on fruit/seed nutrient contents, on a local onion cultivar and on zucchini. The possible variations induced by the inoculation with the bacterial strains on the onion nutritional components were also evaluated. Inoculation resulted in significant growth stimulation and improvement of the mineral concentration of the onion bulb, induced particularly by 5Vm1K and S1Pf1, and in different effects on the flowering of the zucchini plants according to the bacterial strain. The present study provides new information regarding the activity of the five plant growth-promoting bacteria (PGPB) strains on onion and zucchini, two plant species rarely considered by the scientific literature despite their economic relevance.


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