scholarly journals Study of the Modulating Interactions of Multitrait Rhizobacteria Using Zea Mays L. as the Host Plant

2020 ◽  
Vol 10 (2) ◽  
pp. 44-53
Author(s):  
Sana Shakeel ◽  
Ifrah Javaid ◽  
Ambreen Ahmed

Background: Rhizosphere is a soil region closest to roots of the plants inhabiting different types of microorganisms including rhizobacteria. Chemical fertilizers which are conventionally used for increasing crop production are dangerous in terms of minimizing the nutritional value of crops and may also be hazardous for biological agents. Therefore, the use of Plant Growth Promoting Rhizobacteria (PGPR) are favorable for improved crop production over chemical fertilizers. Objectives: The current study highlights the growth promoting traits of bacterial isolates through isolation of rhizospheric bacterial strains from different plants. Methodology: In this study, ten rhizospheric bacterial isolates were used, which were morpho-physiologically characterized and then tested for plant growth-promoting traits i.e., HCN production, ammonification and auxin production. Most of the bacterial strains gave positive results for these plant growth-promoting traits. To study the beneficial effects of these bacteria on plants, plant-microbial interaction assay was conducted using Zea mays. Results: Results revealed that these bacteria enhanced the growth as compared to control plants. Bacterial isolates Streptomyces lydicus (Cn6), Staphylococcus aureus (Cn7) and Bacillus pumilus (PP3) showed strong ammonia producing effects. The isolates Bacillus subtilis (Cn2), PP2 and PP5 exhibited strong potential of HCN production whereas only Streptomyces lydicus (Cn6) and Bacillus pumilus (PP3) were observed to be auxin producers. A maximum increase in fresh weight of the plants was observed in treatment with PP2 showing 94.36% increase over controls. Cn1 showed an increase (26.12%) in shoot length while Cn5 revealed a prominent increase (64.95%) in root length compared to the control plant. The isolates Cn5 and Cn4 showed improvement in the total chlorophyll content of the treated plants with a percentage increase of 100% and 99.82%, respectively compared to the control. Conclusion: In conclusion, these PGPR may be further used in agriculture research for growth improvement.

2015 ◽  
Vol 42 (8) ◽  
pp. 770 ◽  
Author(s):  
Saqib Saleem Akhtar ◽  
Mathias Neumann Andersen ◽  
Muhammad Naveed ◽  
Zahir Ahmad Zahir ◽  
Fulai Liu

The objective of this work was to study the interactive effect of biochar and plant growth-promoting endophytic bacteria containing 1-aminocyclopropane-1-carboxylate deaminase and exopolysaccharide activity on mitigating salinity stress in maize (Zea mays L.). The plants were grown in a greenhouse under controlled conditions, and were subjected to separate or combined treatments of biochar (0% and 5%, w/w) and two endophytic bacterial strains (Burkholderia phytofirmans (PsJN) and Enterobacter sp. (FD17)) and salinity stress. The results indicated that salinity significantly decreased the growth of maize, whereas both biochar and inoculation mitigated the negative effects of salinity on maize performance either by decreasing the xylem Na+ concentration ([Na+]xylem) uptake or by maintaining nutrient balance within the plant, especially when the two treatments were applied in combination. Moreover, in biochar-amended saline soil, strain FD17 performed significantly better than did PsJN in reducing [Na+]xylem. Our results suggested that inoculation of plants with endophytic baterial strains along with biochar amendment could be an effective approach for sustaining crop production in salt-affected soils.


2018 ◽  
Vol 64 (4) ◽  
pp. 253-264 ◽  
Author(s):  
Yanlei Zhu ◽  
Xiaoping She

The objective of this study was to assess the plant-growth-promoting abilities of 45 endophytic bacterial isolates from Ammodendron bifolium through physiological characteristics detection and endophytic bacteria–plant interaction. Each of these isolates exhibited 1 or more plant-growth-promoting traits, but only 11 isolates belonging to the genera Bacillus, Staphylococcus, and Kocuria were capable of promoting seed germination and radicle growth. These results together with the results of the correlation analysis revealed that the completion of seed germination may not be due to IAA production, phosphate solubilization, pellicle formation, and ACC deaminase, protease and lipase production by endophytic bacteria, but may be closely related to amylase and cellulase production. Further, endophytic bacterial isolates with plant-growth-promoting traits may also provide beneficial effects to host plants at different growth stages. Thus, these results are of value for understanding the ecological roles of endophytic bacteria in host plant habitats and can serve as a foundation for further studies of their potential in plant regeneration.


PeerJ ◽  
2018 ◽  
Vol 6 ◽  
pp. e6076 ◽  
Author(s):  
Hadia -e- Fatima ◽  
Ambreen Ahmed

Bacteria are tiny organisms which are ubiquitously found in the environment. These microscopic living bodies are responsible for the flow of nutrients in biogeochemical cycles and fertility imparted to the soil. Release of excessive chromium in agricultural soils due to rapid growth of industries may result in minimizing the fertility of soil in future, which will lead to reduction in crop production. Plant growth promoting bacteria (PGPB) are beneficial to the environment, some of which can tolerate chromium and protect plants against heavy metal stress. The current study aims to identify such chromium-tolerant auxin-producing rhizobacteria and to investigate their inoculation effects on the growth characteristics of Lens culinaris in chromium polluted soils by using two different chromium salts i.e., K2Cr2O7 and K2CrO4 in varying concentrations (0, 50, 100, 200, 400 and 500 µgml−1). The results revealed that Bacillus species are efficient in significantly reducing the deleterious effects of Cr. These effective bacterial strains were able to stimulate the growth of metal effected plants of Lens culinaris which were grown in chromium contaminated environment. Therefore, these plant growth promoting rhizobacteria PGPRs, having both auxin production potential and chromium-resistance ability, are considered as efficient micro-factories against chromium pollution.


2015 ◽  
Vol 2 (1) ◽  
pp. 1-8
Author(s):  
Moonmoon Nahar Asha ◽  
Atiqur Rahman ◽  
Quazi Forhad Quadir ◽  
Md Shahinur Islam

A laboratory experiment was performed to isolate some native rhizobacteria that could be used as bioinoculants for sustainable crop production. A total of 43 rhizobacteria were isolated from undisturbed plant rhizosphere soils of three different locations of Bangladesh and evaluated their plant growth promoting traits, both direct and indirect. The study has screened out isolates on the basis of their phosphorous solubilization and nitrogen (N) fixation. The phosphate solubilization assay in National Botanical Research Institute of Phosphate (NBRIP) medium revealed that 12 bacterial isolates were able to solubilize tricalcium phosphate and the rhizobacteria M25 showed best performance with a PSI of 3.33 at 5 day. Exactly 47% (20 isolates) of the isolated rhizobacteria were able to grow in N-free Winogradsky’s medium, which is an indication of potential N2-fixers. Among the 20 potential N-fixers, 15 were able to grow within 24 hours of incubation indicating that they are more efficient in Nfixation. The present study successfully isolated and characterized 43 rhizobacteria. Some of these isolated rhizobacteria have potential plant growth promoting traits and are potential plant growth promoting rhizobacteria (PGPR) candidate. Considering all plant growth promoting traits, the isolate F37 was the best followed by M6. However, further experiments are needed to determine the effectiveness of these isolates under in vitro and different field conditions to understand the nature of interaction with the plant and environment.Res. Agric., Livest. Fish.2(1): 1-8, April 2015


2021 ◽  
Vol 4 ◽  
Author(s):  
Grace Flavyeliz Sinong ◽  
Michiko Yasuda ◽  
Yoshiyuki Nara ◽  
Chol Gyu Lee ◽  
Khondoker Mohammad Golam Dastogeer ◽  
...  

A nature farming system is an ecological farming practice that entails cultivating crops without using chemical fertilizers and pesticides. To understand the diversity and functions of root microbiomes associated with nature farming systems, we compared the root microbial community of rice under nature farming conditions with those under conventional farming conditions. High-throughput amplicon analysis demonstrated a higher abundance and greater diversity of the root microbiome under unfertilized nature farming conditions than under conventional conditions. The application of chemical fertilizers reduced the microbial diversity and abundance of some beneficial taxa important for plant growth and health. Subsequently, we isolated and identified 46 endo- and epiphytic bacteria from rice roots grown under nature farming conditions and examined their plant growth-promoting activity. Six potential isolates were selected for plant growth assessment in insoluble P- and K-containing media. Most of the isolates promoted rice growth, and Pseudomonas koreensis AEPR1 was able to enhance rice growth significantly in both insoluble P- and K-containing media. Our data indicated that nature farming systems create a distinct root microbiome that is comparatively more diverse and supports plant growth under low-input cultivation practices than under conventional practices. The potential isolates could be exploited as sources with potential applications in sustainable agriculture.


Plant Disease ◽  
2000 ◽  
Vol 84 (3) ◽  
pp. 306-308 ◽  
Author(s):  
S. A. Enebak ◽  
W. A. Carey

Trials conducted in 1997 and 1998 tested eight strains of plant growth-promoting rhizobacteria (PGPR) for their capacity to induce systemic protection in loblolly pine to the causal agent of fusiform rust. Pine seeds were treated with bacteria at time of sowing, and seedlings were artificially inoculated with basidiospores of Cronartium quercuum f. sp. fusiforme 1 month later. Six months after basidiospore inoculation, seedlings were evaluated for the fusoid swelling or galls characteristic of rust infection. Compared with seedlings from seed not treated with bacteria, two bacterial isolates, Bacillus pumilus (SE34) and Serratia marcescens (90–166), significantly (P = 0.05) reduced the number of galls in 1997 and 1998. Combined data from 1997 and 1998 resulted in two additional isolates, B. pumilus (INR7) and B. pumilus (SE52), significantly (P = 0.05) reducing the number of galls. Averaged over both years, 31% of control seedlings were infected with fusiform rust, while those seedlings treated with bacterial strains SE34, 90–166, INR7, and SE52 had 13, 14, 15, and 16% infection, respectively. These four PGPR strains appear to have induced systemic resistance to fusiform rust in loblolly pine, resulting in less infection over nontreated control seedlings.


2018 ◽  
Vol 10 (1) ◽  
pp. 518-521 ◽  
Author(s):  
Ritika Modi ◽  
Veena Khanna

In pigeonpea due to the prevailing high temperature, poor nodulation have usually been observed as a limiting factor in its productivity. Plant growth promoting traits of 5 pigeonpea rhizobacterial isolates out of 32, selected on the basis of maximum growth at 30, 40 and 50°C, were evaluated for their potential application in enhancing symbiosis and plant growth of pigeonpea. The level of IAA at 30, 40 and 50°C varied from 0.95-20.96 μg/ml, 1.21- 34.82 μg/ml and 0.16-17.34 μg/ml in the presence of tryptophan respectively. Maximum flavonoid production and siderophore production was recorded bacterial isolates with S12p6 (6.68 μg/ml) at 30°C and S1p1 (4.2 cm) at 40°C respectively. Isolates S1p1 and S12p6 showed relatively superior production of growth hormone, flavonoid-like compounds and siderophores can further be tested as co-inoculant with recommended Rhizobium for studying their efficacy under field conditions for symbiotic parameters and growth of pigeonpea.


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