Promotion of plant growth and inhibition of enzymic degradation of indole-3-acetic acid by metabolites of carbofuran, a carbamate insecticide

1977 ◽  
Vol 55 (5) ◽  
pp. 574-579 ◽  
Author(s):  
T. T. Lee

The carbamate insecticide carbofuran (2,2-dimethyl-2,3-dihydrobenzofuranyl-7-N-methyl carbamate) and three of its metabolites (7-hydroxy-2,2-dimethyl-2,3-dihydrobenzofuran (III), 3,7-dihydroxy-2,2-dimethyl-2,3-dihydrobenzofuran (IV), and 3-keto-7-hydroxy-2,2-dimethyl-2,3-dihydrobenzofuran (V)) stimulated growth in the pea stem segment assay in the presence, but not absence, of a low concentration of indole-3-acetic acid (IAA). The metabolites were more active than carbofuran itself. The synergistic effect on growth was specific with IAA since it was not observed in the presence of other auxins.Metabolites III, IV, and V and, to a lesser degree, carbofuran were found to be inhibitory to IAA degradation catalyzed by pea stem tissue or purified horseradish peroxidase (EC 1.11.1.7). Comparison of the relative activities of the compounds in the inhibition of IAA degradation and in the promotion of plant growth suggests a causal relationship. The implication is that carbofuran may promote plant growth through the inhibitory action of its metabolites on enzymic breakdown of IAA, thus preserving a critical level of IAA required for growth promotion.

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.


2013 ◽  
Vol 26 (5) ◽  
pp. 546-553 ◽  
Author(s):  
Ana Zúñiga ◽  
María Josefina Poupin ◽  
Raúl Donoso ◽  
Thomas Ledger ◽  
Nicolás Guiliani ◽  
...  

Although not fully understood, molecular communication in the rhizosphere plays an important role regulating traits involved in plant–bacteria association. Burkholderia phytofirmans PsJN is a well-known plant-growth-promoting bacterium, which establishes rhizospheric and endophytic colonization in different plants. A competent colonization is essential for plant-growth-promoting effects produced by bacteria. Using appropriate mutant strains of B. phytofirmans, we obtained evidence for the importance of N-acyl homoserine lactone-mediated (quorum sensing) cell-to-cell communication in efficient colonization of Arabidopsis thaliana plants and the establishment of a beneficial interaction. We also observed that bacterial degradation of the auxin indole-3-acetic acid (IAA) plays a key role in plant-growth-promoting traits and is necessary for efficient rhizosphere colonization. Wildtype B. phytofirmans but not the iacC mutant in IAA mineralization is able to restore promotion effects in roots of A. thaliana in the presence of exogenously added IAA, indicating the importance of this trait for promoting primary root length. Using a transgenic A. thaliana line with suppressed auxin signaling (miR393) and analyzing the expression of auxin receptors in wild-type inoculated plants, we provide evidence that auxin signaling in plants is necessary for the growth promotion effects produced by B. phytofirmans. The interplay between ethylene and auxin signaling was also confirmed by the response of the plant to a 1-aminocyclopropane-1-carboxylate deaminase bacterial mutant strain.


2020 ◽  
Vol 10 (1) ◽  
pp. 21
Author(s):  
Agustina Monalisa Tangapo

Potensi Bakteri Endofit Ubi Jalar (Ipomoea batatas L.) dalam Menghasilkan Hormon Indole Acetic Acid (IAA) dengan Penambahan L-triptofan(Potential of endophytic bacteria of sweet potato (Ipomoea batatas L.) in producing Indole Acetic Acid (IAA) with the addition of L-tryptophan) Agustina Monalisa TangapoProgram Studi Biologi FMIPA Universitas Sam RatulangiJl. Kampus Unsrat, Manado 95115*Email korespondensi:[email protected] (Article History: Received 5-01-2019; Revised 15-01-2020; Accepted 05-02-2020) ABSTRAKAsosiasi bakteri-tanaman, dapat mempengaruhi produktivitas tanaman secara langsung dan tidak langsung. Secara langsung, salah satunya yaitu bakteri dapat memproduksi dan menyekresikan zat pengatur tumbuh indole-3-acetic acid (IAA, auksin). Penelitian ini bertujuan untuk menguji kemampuan bakteri endofit ubi jalar dalam menghasilkan IAA. Metode analisis IAA dilakukan dengan metode kolorimetri. Analisis produksi IAA dilakukan dengan penambahan dan tanpa penambahan L-triptofan. Hasil penelitian menunjukkan bahwa tanpa penambahan L-triptofan, diperoleh sejumlah 19 jenis yang menghasilkan IAA dengan kisaran konsentrasi 0,29-7,21 mg/L. Dengan penambahan L-triptofan, jumlah jenis positif dan konsentrasi IAA yang dihasilkan meningkat signifikan. Jumlah jenis positif 20 jenis (91%) dan konsentrasi IAA yang dihasilkan mencapai kisaran 0,96-115,63 mg/L.Kata kunci: bakteri endofit; IAA; ubi jalar; L-triptofan ABSTRACTPlant-bacteria associations, can promote plant growth by both direct and indirect mechanisms. One of direct mechanisms is that bacteria can produce and secrete indole-3-acetic acid (IAA, auxin) growth regulators. This study aims to examine the ability of sweet potato endophytic bacteria to produce IAA. The detection of IAA production was conducted by colorimetric technique. IAA production analysis was carried out with addition and without addition of L-tryptophan. Without the addition of L-tryptophan, a total of 19 species produced IAA with a concentration range of 0.29-7.21 mg/L. With the addition of L-tryptophan, the number of positive species and the concentration of IAA produced increased significantly. The number of positive species was 20 species (91%) and the concentration of IAA produced reached a range of 0.96-115.63 mg/L.Keywords: endophytes bacterial; IAA; sweet potato; L-tryptophan


2020 ◽  
Author(s):  
Wenjing Wang ◽  
Clement Kyei Sarpong ◽  
Chun Song ◽  
Xiaofeng Zhang ◽  
Yuefeng Gan ◽  
...  

ABSTRACTThe solubilization and mineralization of phosphorus by phosphate-solubilizing bacteria (PSB) is one of the most important bacterial physiological characteristics in the soil biogeochemical cycle. Through the isolation and screening of microorganisms in the rhizosphere soil of intercropped soybean in Ya’an, Renshou and Chongzhou, 9 PSBs with high phosphorus solubilizing ability were identified. It mainly belongs to Bacillus and Pseudomonas. The phosphate solubility of Bacillus aryabhattai B8W22 is as high as 388.62 µg·mL-1. The physiological and biochemical characteristics of each strain showed that it can secrete organic acids such as formic acid, acetic acid lactic acid and pyruvic acid. In addition, all strains can produce indole acetic acid and siderophores that promote plant growth. Seed germination experiments also showed that the phosphorus solubilizing bacteria isolated in this research have a certain ability to promote plant growth.IMPRTANCEBacillus aryabhattai from rhizosphere soil of intercropped soybean has high phosphate-solubilizing ability, could produce indole acetic acid and siderophores that promote plant growth, and are of great significance in reducing the application of chemical phosphate fertilizers and promoting sustainable agricultural development.


F1000Research ◽  
2018 ◽  
Vol 7 ◽  
pp. 112 ◽  
Author(s):  
Arun Karnwal ◽  
Aradhana Dohroo

Background: It is assumed that plant growth regulators produced by beneficial bacterial species could also influence plant growth. IAA is a major plant growth regulator responsible for stimulation of plant growth. There are several microorganisms which are naturally responsible for L- tryptophan metabolism. Methods: In total, 56 indigenous morphologically distinct isolates from rice roots were selected and subsequently characterized with biochemical tests, 16S rRNA sequencing and plant growth promoting activities. Pseudomonas fluorescens RE1 (GenBank: MF102882.1) and RE17 (GenBank: MF103672.1) endophytes resulted in better PGP activity against the other 54 isolates. Both endophytes were tested to screen indole-3-acetic acid production ability in pure culture conditions with L-tryptophan at 0, 50, 100, 200 and 500µg/ml concentrations. Results: P. fluorescens RE1 was recorded efficient for indole production in comparison to P. fluorescens RE17 at various L-tryptophan concentrations. P. fluorescens RE1 was shown to produce between 0.8 µg/ml and 11.5µg/ml of indole at various tryptophan concentrations, while RE17 produced between 1.2µg/ml and 10.2µg/ml. At 200 and 500µg/ml tryptophan concentration, P. fluorescens RE17 produced 7.4pmol/ml and 9.3pmol/ml IAA, respectively.  Conclusions: Inoculation of maize seed with P. fluorescens RE1 and RE17 showed a significantly higher level of IAA production in comparison to non-inoculated seeds. Current study outcomes proved that plant growth regulators produced by Pseudomonas species could also play a critical role in plant growth promotion.


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