scholarly journals Modulation of IAA Production in Cyanobacteria by Tryptophan and Light

2010 ◽  
Vol 59 (2) ◽  
pp. 99-105 ◽  
Author(s):  
RADHA PRASANNA ◽  
MONICA JOSHI ◽  
ANUJ RANA ◽  
LATA NAIN

Cyanobacteria represent less a investigated group of prokaryote, in terms of their plant growth promoting potential, especially in relation to the production of phytohormones. The present investigation was aimed towards analyzing growth kinetics, indole acetic acid (IAA) production and acetylene reduction activity (ARA) as an index of nitrogen fixation in two selected cyanobacterial strains belonging to the genus Anabaena, as influenced by tryptophan supplementation and light:dark conditions. Interesting observations were recorded in terms of enhancement of IAA production accompanied by protein and chlorophyll accumulation in the two cyanobacterial strains grown in media without tryptophan and incubated under light:dark or continuous light conditions. Colorimetric and chromatographic analyses supported the observations that tryptophan is not essential as a precursor for IAA biosynthesis in these cyanobacteria. Further study is in progress to identify genes involved in the tryptophan independent pathway for IAA biosynthesis.

Horticulturae ◽  
2018 ◽  
Vol 4 (4) ◽  
pp. 53 ◽  
Author(s):  
Sabitri Adhikari Dhungana ◽  
Fumihiko Adachi ◽  
Shohei Hayashi ◽  
Ramesh Raj Puri ◽  
Kazuhito Itoh

Endophytic bacteria form a symbiotic relation with plants and generally cause no harmful effects to the host plants. In a previous study, we isolated eight bacterial endophytes from sweet potato plants harvested in Salyan, Nepal. These endophytes showed plant growth-promoting properties as a mixed culture. In this study, we evaluated the ability of these strains to produce indole-3-acetic acid (IAA) and to fix nitrogen. Based on these results, we selected two strains, Klebsiella sp. Sal 1 and Enterobacter sp. Sal 3, and evaluated their ability to promote plant growth. IAA production activity peaked at 15–60 mg NH4NO3/L in plant-free medium. Similarly, acetylene reduction activity peaked at 0–6.25 mg NH4NO3/L. Both strains successfully colonized plants, promoted the growth of tomatoes, and induced phenotypes in plants consistent with IAA exposure. This suggests that these strains promote plant growth by producing IAA inside the plant, where nitrogen levels are expected to be low.


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.


Agriculture ◽  
2021 ◽  
Vol 11 (11) ◽  
pp. 1036
Author(s):  
Xuqing Li ◽  
Dingyi Li ◽  
Jianli Yan ◽  
Ya Zhang ◽  
Hong Wang ◽  
...  

Land reclamation may expand the supply of usable land for food security. Immature soil is not suitable for plant growth and needs to be amended by the addition of organic matter and plant growth-promoting (PGP) microorganisms. However, the effects of different PGP fungi on plant growth in immature soil are largely unexplored. In order to obtain beneficial soil microorganisms with a good PGP ability in new reclamation land, 162 fungal isolates were isolated from different abandoned wastelands, four isolates of which were obtained in this study by the screening of P solubilization, siderophore production, and indole acetic acid (IAA) production. The result of this study revealed that isolate HZ123 had the highest ability to solubilize P and produce siderophores and IAA, followed by HZ23, HZ10, and HZ06. Based on the results of morphological and molecular analyses, isolate HZ06 was identified as Penicillium oxalicum, isolates HZ23 and HZ10 were identified as Aspergillus brunneoviolaceus, and isolate HZ123 was identified as Aspergillus tubingensis. Furthermore, the results of in vivo PGP assays demonstrated that isolate HZ123 has a minimal negative effect on the growth of eggplant; however, the other three isolates, particularly isolate HZ06, caused the greatest increase in eggplant biomasses. Overall, these results indicate that isolate HZ06 has great potential as a PGP fungus to develop biofertilizer for application in eggplant production in immature soil from new reclamation land.


2017 ◽  
Vol 9 (2) ◽  
pp. 920-923
Author(s):  
Gurmeet Kaur ◽  
Veena Khanna

PGPR strains exhibiting optimum functional traits at high temperature and are compatible with Rhizobium can be used in pigeonpea as biofertilizer. A total of 45 rhizobacterial isolates were isolated from 13 different locations of pigeonpearhizospheric soil of Punjab. Out of the 45 isolates, 5 isolates selected on the basis of maximum growth at 30°C and 40°C were morphologically and biochemically characterized, belonging to genera Pseudomonas (P-6, P-9) and Bacillus (P-30, P-31, P-32). Selected isolates were further evaluated for the production of IAA, GA, SA and flavonoids. IAA production was estimated in the range from 0.45-25.13 μg/ml and 4.62-34.34 μg/ml in the presence of tryptophan at 30 and 40°C respectively. Maximum gibberellic acid production was recorded with P-30 (108.99 μg/ml and 112.12 μg/ml) at 30 and 40°C respectively. Similarly maximum salicylic acid was also estimated with P-30 (157.2 μg/ml) followed by P-31 (141.0 μg/ml) at 40°C. All the isolates were also found to produce flavonoids ranged from 2.98 - 4.40 μg/ml at 40 °C. Isolates P-30, P-31 showed superior production of growth hormones and flavonoid-like compounds can further be tested under the field conditions to enhance growth and yield of pigeonpea.


Author(s):  
Giuseppe Haydn Lacorte ◽  
Remedios S. Flamiano ◽  
Malona V. Alinsug ◽  
Paolo M. Tagaloguin

Rhizospheric bacteria (PGPR) associated with 5 banana cultivars planted in SOCCSKSARGEN were studied. Microbial population in newly established and old plantation was compared. Bacteria were purified and their beneficial characteristics were determined. This study was able to collect one hundred twenty (120) bacterial isolates, 20 (17%) of which were nitrogen-fixers, nineteen (19/20) were phosphate solubilizers and seventeen (17/20) were IAA producers. From this study, five bacterial isolates coded PE05, RS10, PE11, PE13, and PE18 were found positive for nitrogen fixation, phosphate solubilization and IAA production which may be further evaluated for their potential application in the formulation of biofertilizers for banana cultivation. Read full article here.


2019 ◽  
Vol 11 (2) ◽  
pp. 346-351
Author(s):  
Deepika Chhabra ◽  
Poonam Sharma

Bacteria that colonize plant tissues other than rhizobia and are beneficial for plant growth referred to non rhizobial plant growth-promoting endophytic bacteria (PGPEB). This study was designed to assay the biocontrol activity of plant growth promoting endophytic bacterial isolates those found positive for P. solubilization, ACC deaminase, Indole acetic acid and Gibberelic acid production. These bacterial isolates were obtained from chickpea (Cicer arietinum L.) tissues (roots and nodules).  In a previous study a total of 263 non rhizobial endophytic bacterial isolates were isolated. Out of 263 isolates, 64.5% and 34.5% were Gram positive and negative, respectively. Further for biochemical characterization, catalase, oxidase, citrate utilization, nitrate reduction, methyl red and Voges Proskauer’s tests, were performed. On the basis of P solubilization, ACC deaminase, Indole acetic acid and Gibberelic acid production 75 potential isolates were selected and screened for their biocontrol activity viz. (production of cell wall degrading enzymes, production of HCN and fluorescent pigment). Out of 75 isolates, only 29 isolates produced cellulase, 64 isolates were able to produce protease and 28 were positive for both cellulose and protease. Of 75 endophytic isolates 12 isolates (7 from root tissue and 5 from nodules tissue, respectively) were positive for HCN production and 16 isolates were found to be fluorescent pigment producer under µv ligh. As chemical fertilizers and pesticides have detrimental effects on the environment. So these bacterial endophytic isolates will be used not only as a biofertilizer because of their plant growth promotional activities but also used as an alternative of synthetic chemicals for control of several plant diseases.


2016 ◽  
Vol 3 (1) ◽  
pp. 105-113 ◽  
Author(s):  
Mohammad Mosharraf Hossain ◽  
Keshob Chandra Das ◽  
Sabina Yesmin ◽  
Syfullah Shahriar

Plant growth promoting rhizobacteria (PGPR) are beneficial bacteria that colonize plant roots and enhance plant growth by a wide variety of mechanisms. Ten isolates of bacteria designated as SS01, SS02, SS03, SS04, SS05, SS06, SS07, SS08, SS09 and SS10 were successfully isolated and morphologically and biochemically characterized. Subsequently to investigate the effect of PGPR isolates on the growth of chickpea, a pot culture experiment was conducted in 2013 at National Institute Biotechnology, Bangladesh net house. Prior to seeds grown in plastic pots, seeds were treated with PGPR isolates and seedlings were harvested after 21 days of inoculation. All the isolates were gram negative in reaction, catalase positive, produced indole acetic acid (IAA) as well as performed phosphate solubilization, able to degrade cellulose and have the adaptability in wide range of temperature and showed positive growth pattern in medium. Most of isolates resulted in a significant increasing of shoot length, root length and dry matter production of shoot and root of chickpea seedlings. Application of PGPR isolates significantly improves the percentage of seed germination under saline conditions. The present study, therefore suggested that the use of PGPR isolates SS04, SS10 and SS08 as inoculants biofertilizers might be beneficial for chickpea cultivation in saline conditionRes. Agric., Livest. Fish.3(1): 105-113, April 2016


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