High Amount Of Indole Acetic Acid Research Articles

Overproduction of Some Plant Growth Promoters by Rhizospheric Microorganisms on Natural Medium

Considering the nutritional values of Mentha viridis. L and Aloe veraplants, these plants can be utilized for the production of alternative cultivation media. The cost of artificial culture media is very high, and some components may be unavailable. Use of the plant-based culture media would drastically reduce the expense of the synthetic media. Fifteen bacterial isolates were isolated from Aloe vera rhizosphere, nine bacterial and nine actinomycetes isolates were isolated from Mentha viridis rhizosphere both cultivated in Sirs EL- Layan, El-Menoufia governorate, Egypt. In-vitroscreening was done for the production of indole acetic acid (IAA) and phosphorus solubilization. Results revealed that bacterial isolate No. MB4 produced a high amount of IAA(36.51 μg/ml) on the Mentha-based culture medium, No. A6 showed maximum IAA production (16.25μg/ml) on the Aloe vera-based culture medium and isolate No. MA6 was efficient in phosphorus solubilization (867.85μg/ml) that was isolated from the Mentha viridis. L rhizosphere.16s rRNA analysis of these isolates revealed they are (Pseudomonas monteilii strain CIP 104883, Streptomyces rochei strain DW3 and Kosakonia radicincitans strain DSM 16656 respectively.

Root priming with Bacillus spp. against bacterial wilt disease of tomato caused by Ralstonia solanacearum

Bacillus spp. have long been used as biological control organisms against plant bacterial diseases but the mechanisms by which the bacteria confer protection against the pathogens are not properly understood. Among nine strains of Bacillus spp. three of them, viz. NBAII 63 (B. megaterium), NBAII 71 (B. cereus) and NBAII 65 (B. megaterium) were found highly inhibitory against R. solanacearum. These strains of Bacillus spp. produced indole acetic acid (IAA) and siderophore and solubilized the phosphorous. High amount of IAA (174.2 μg/ml) and siderophore (1.32μg/ml) production followed by the highest phosphorous solubilization (53.3 μg/ml) by the strain NBAII 63 were found. These three potential Bacillus strains showed the increased activity of defense related enzymes, viz. peroxidase (PO), polyphenoloxidase (PPO), phenylalanine ammonia-lyase (PAL) and total phenols in pre treated tomato plants challenged with R. solanacearum. Significant activities of PO, PPO, PAL were observed at 8 days after the treatment of antagonist and declined gradually afterwards. The maximum phenol content (185 μg/g of plant tissue) was observed in the tomato plants whose roots were treated with Bacillus strain 63 at 8 days after inoculation treatment. These Bacillus strains could be used as potential biocontrol agent for the management of bacterial wilt disease of tomato.

Exploitation of Rhizobacteria for Functional Traits in Mungbean

The enrichment of plant rhizosphere with beneficial bacteria is a strategy that favours the production of more vigorous seedlings, which is essential for the success of legume cultivation. The aim of this study was to select rhizobacteria that are able to act as plant growth-promoting rhizobacteria (PGPR). A total of 17 rhizobacteria belonging to genera Bacillus (8), Pseudomonas (5) and Azotobacter (4) from mungbean rhizosphere were selected on the basis of their ability to solubilize phosphate. These selected rhizobacteria were further characterized for Plant Growth Promoting (PGP) traits for quantitative phosphate solubilisation, Indole Acetic Acid (IAA), organic acid production and Intrinsic antibiotic spectra (IAR), control of phytopathogen via siderophore and cellulase production and stress tolerant management by 1-aminocyclopropane-1-carboxylate (ACC) deaminase activity. Significantly high phosphate was solubilized by strain of Bacillus sp. B2 (9.77 mg ml−100) followed by strain of Pseudomonas sp. P10 (9.14 mg ml−100) and strain of Azotobacter sp. A3 (8.98 mg ml−100). In the presence of L-trptophan P10, A3 and B2 were also able to produce significant high amount of IAA i.e. 55.6 μg ml−1, 52.6 μg ml−1 and 50.3 μg ml−1 respectively and they also produced organic acid, siderophore and cellulase. Of 17 rhizobacterial isolates, 11 were found compatible with Rhizobium sp. vigna (LSMR1) in-vitro. IAR pattern revealed 52.9% of rhizobacteria resistant to ampicillin (10 μg disc−1) and chloramphenicol (25 μg disc−1). ACC deaminase activity was measured by their growth in DF medium supplemented with ACC (OD 600 ranged from 0.117 to 0.432) as nitrogen (N) source. In the present investigation, rhizobacterial isolates viz, B2, P10 and A3 were found most promising for multiple activities (PGP traits, biocontrol and stress tolerant activities) and can be evaluated in-vivo for their possible role in mungbean growth and development.

Content of indoleacetic acid and its metabolism in root nodules ofMelilotus alba

The root nodules ofMelilotus alba, a leguminous fodder herb, contain a high amount of indoleacetic acid (IAA). The tryptophan pool present in the nodule might serve as a source for the IAA production. Metabolism of IAA in the nodules was evidenced by the presence of IAA-metabolizing enzymes, IAA oxidase and peroxidase. A high amount of IAA was produced by the symbiont isolated from the nodules in culture, when supplemented with tryptophan. For IAA production, the bacteria preferred thel-isomer over thedl- ord-isomer of tryptophan. The possible role of nodular IAA production on the legume-Rhizobium symbiosis is discussed.

Studies on Root Nodules of Leguminous Trees II. The Bioproduction of Different Phytohormones in Root Nodules of Samanea saman (JACQ.) MERRIL and by Its Rhizobial Microsymbiont

Summary The mature nodules of Samanea saman contained higher levels of indole acetic acid (IAA), gibberellic acid-like substances (GA), cytokinin-like substances (CK) and abscisic acid-like substances (ABA) than its roots. Tryptophan level was also higher in root nodule. The metabolism of IAA was evidenced by the presence of IAA oxidising enzymes in the root nodules and roots. Rhizobium sp. from the nodules produced high amount of IAA in culture when supplemented with tryptophan. The Rhizobium sp. preferred L-isomer over DL- or D-isomer of tryptophan for IAA production.