scholarly journals Screening of plant growth-promoting rhizobacteria from maize (Zea mays) and wheat (Triticum aestivum)

2012 ◽  
Vol 12 (51) ◽  
pp. 6170-6185
Author(s):  
A Karnwal ◽  

Plant growth-promoting rhizobacteria (PGPR) are free-living soil-borne bacteria that colonize the rhizosphere and have great importance in governing the functional property of terrestrial ecosystems. In this study, rhizospheric bacteria were isolated from maize and wheat and screened for their plant growth promoting activities. These isolates were identified as Pseudomonas , Bacillus , Azospirillum and Azotobacter species. All isolates were tested for their indole acetic acid (IAA) production ability. All isolates produce the varying amount s o f IAA ranging from 0.6- 2.7 μg/ml. The highest concentration of IAA was produced by bacterial strain Bacillus subtilis AK31. A series of growth pouch and pot experiments were conducted to study the effect of bacterial inoculants on the growth of maize and wheat. It was concluded that IAA plays a key role i n the growth promotion of roots in maize and wheat in growth pouch study. In maize, isolate AK1, AK21, AK31 and AK8 showed high indole acetic acid (6.86, 7.11, 7.11 and 7.36 pmol/ml, respectively) and root elongation activity ( 4.10, 5.00, 5.00 and 3.80 cm, respectively) after 96h of growth. In wheat, bacterial strains AK31, AK2, AK14, AK32 and AK15 showed high IAA ( 6.59, 5.66, 5.35, 7.53 and 5.66 pmol/ml, respectively) and root elongation ( 6.07, 4.00, 5.20, 6.90 and 5.20 cm, respectively) activity after 96h of growth. In pot experiments, Bacillus sp. AK21, Bacillus subtilis AK31, Azotobacter diazotrophicus AK14, Microbacterium sp. AK19 and Pseudomonas fluorescens AK32 showed effective results in term s of increase in root and shoot dry weight in maize (123, 130, 121, 120, 124g and 116, 126, 116, 114, 120g/pot, respectively) and wheat (130, 135, 125, 118, 140g and 105, 106, 110, 102, 110g/pot, respectively), in comparison to controls of maize and wheat crops. Thus, it might be concluded that PGPR strains AK21, AK31, AK14, AK19 and AK32 could be used as crop- enhancer and bio- fertilizer for production of maize and wheat .

1996 ◽  
Vol 42 (3) ◽  
pp. 279-283 ◽  
Author(s):  
T. C. Noel ◽  
C. Sheng ◽  
C. K. Yost ◽  
R. P. Pharis ◽  
M. F. Hynes

Early seedling root growth of the nonlegumes canola (Brassica campestris cv. Tobin, Brassica napus cv. Westar) and lettuce (Lactuca saliva cv. Grand Rapids) was significantly promoted by inoculation of seeds with certain strains of Rhizobium leguminosarum, including nitrogen- and nonnitrogen-fixing derivatives under gnotobiotic conditions. The growfh-promotive effect appears to be direct, with possible involvement of the plant growth regulators indole-3-acetic acid and cytokinin. Auxotrophic Rhizobium mutants requiring tryptophan or adenosine (precursors for indole-3-acetic acid and cytokinin synthesis, respectively) did not promote growth to the extent of the parent strain. The findings of this study demonstrate a new facet of the Rhizobium–plant relationship and that Rhizobium leguminosarum can be considered a plant growth-promoting rhizobacterium (PGPR).Key words: Rhizobium, plant growth-promoting rhizobacteria, PGPR, indole-3-acetic acid, cytokinin, roots, auxotrophic mutants.


2001 ◽  
Vol 47 (7) ◽  
pp. 642-652 ◽  
Author(s):  
Andrei A Belimov ◽  
Vera I Safronova ◽  
Tatyana A Sergeyeva ◽  
Tatyana N Egorova ◽  
Victoria A Matveyeva ◽  
...  

Fifteen bacterial strains containing 1-aminocyclopropane-1-carboxylate (ACC) deaminase were isolated from the rhizoplane of pea (Pisum sativum L.) and Indian mustard (Brassica juncea L.) grown in different soils and a long-standing sewage sludge contaminated with heavy metals. The isolated strains were characterized and assigned to various genera and species, such as Pseudomonas brassicacearum, Pseudomonas marginalis, Pseudomonas oryzihabitans, Pseudomonas putida, Pseudomonas sp., Alcaligenes xylosoxidans, Alcaligenes sp., Variovorax paradoxus, Bacillus pumilus, and Rhodococcus sp. by determination of 16S rRNA gene sequences. The root elongation of Indian mustard and rape (Brassica napus var. oleifera L.) germinating seedlings was stimulated by inoculation with 8 and 13 isolated strains, respectively. The bacteria were tolerant to cadmium toxicity and stimulated root elongation of rape seedlings in the presence of 300 µM CdCl2 in the nutrient solution. The effect of ACC-utilising bacteria on root elongation correlated with the impact of aminoethoxyvinylglycine and silver ions, chemical inhibitors of ethylene biosynthesis. A significant improvement in the growth of rape caused by inoculation with certain selected strains was also observed in pot experiments, when the plants were cultivated in cadmium-supplemented soil. The biomass of pea cv. Sparkle and its ethylene sensitive mutant E2 (sym5), in particular, was increased through inoculation with certain strains of ACC-utilising bacteria in pot experiments in quartz sand culture. The beneficial effect of the bacteria on plant growth varied significantly depending on individual bacterial strains, plant genotype, and growth conditions. The results suggest that plant growth promoting rhizobacteria containing ACC deaminase are present in various soils and offer promise as a bacterial inoculum for improvement of plant growth, particularly under unfavourable environmental conditions.Key words: ACC deaminase, cadmium, ethylene, Indian mustard, pea, phytoremediation, rape, rhizobacteria.


2020 ◽  
Vol 3 (2) ◽  
pp. 210-219
Author(s):  
Ika Agus Rini ◽  
Indah Oktaviani ◽  
Muhammad Asril ◽  
Revi Agustin ◽  
Fina Khaerunissa Frima

IAA adalah produk paling umum dari metabolisme L-triptofan yang dapat diproduksi oleh beberapa mikroorganisme. Beberapa mikroorganisme yang memiliki potensi menghasilkan IAA adalah bakteri rhizosfer pada tanaman Leguminosae, salah satunya adalah akasia. Acacia mangium, juga dikenal sebagai akasia, adalah pohon yang tumbuh cepat. Namun, akasia adalah tanaman invasif. Tanaman akasia memiliki bintil yang merupakan hasil simbiosis akar tanaman dan bakteri. Simbiosis ini dapat mempengaruhi kesuburan tanah. Banyak potensi yang dapat digali dari bakteri tanah, khususnya di rhizosfer. Tujuan dari penelitian ini adalah untuk mengisolasi dan mengidentifikasi bakteri pada rizosfer tanaman akasia yang mampu menghasilkan IAA sebagai salah satu potensi untuk kandidat PGPR (Plant Growth Promoting Rhizobacteria). Metode yang digunakan meliputi pengambilan sampel, isolasi bakteri penghasil IAA, pemurnian bakteri, identifikasi bakteri dan uji biokimia, pembuatan kurva tumbuha bakteri, dan uji isolat bakteri pelarut fosfat. Hasil isolasi bakteri rhizosfer diperoleh sebanyak 10 isolat bakteri yang memiliki karakteristik berbeda secara morfologi.  Berdasarkan hasil identifikasi bakteri berdasarkan pewarnaan Gram, bakteri tersebut masuk ke dalam genus Bacillus dan terdapat 5 isolat bakteri yang memiliki kemampuan menghasilkan IAA dan melarutkan fosfat sehingga bakteri tersebut memiliki potensi sebagai pupuk hayati.


2021 ◽  
Vol 48 (2) ◽  
Author(s):  
Narjes H. Dashti ◽  
◽  
Nedaa Y. Ali Al-Sarraf ◽  
Vineetha M. Cherian ◽  
Magdy S. Montasser ◽  
...  

Indole acetic acid (IAA) production is one of the distinctive traits of plant growth-promoting rhizobacteria (PGPR). Ten different rhizobacterial strains were isolated from the roots of tomato crops (Solanum lycopersicum L.), grown in Kuwait, and then screened for their plant growth-promoting abilities, with emphasis on IAA production. The isolated strains were identified by 16S partial r-RNA sequencing and further characterized by conventional biochemical tests. Based on the nucleotide sequence analysis and homology of the isolates, a phylogenetic tree was constructed. The plant growth-promoting abilities of the strains were determined by testing for ammonium production, hydrogen cyanide and acid production, growth in nitrogen-free media, phosphate solubilization, and IAA production. The potential IAA PGPRs were re-applied onto the rhizosphere of green-house grown tomato plants to determine their effects on tomato growth. The results have indicated that all isolated strains were able to produce indole acetic acid even without the presence of a tryptophan precursor.


Sign in / Sign up

Export Citation Format

Share Document