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1.
C. K. Deepa Syed G. Dastager Ashok Pandey 《World journal of microbiology & biotechnology》2010,26(12):2277-2283
A Gram-positive rod-shaped bacterium isolated on nutrient agar plates incubated at 28 ± 2°C. The identity of the bacterium
was confirmed by sequencing of the 16S rRNA gene and it reveals that it shares highest similarity with Bacillus thioparus CECT 7196T (99.08%). It was capable of growing at temperatures ranging from 4 to 40°C, but optimum growth was observed at 28 ± 2°C.
Strain NII-0902 is endowed with multiple plant growth promotion attributes such as phosphate solubilization, Indole acetic
acid (IAA), siderophore and HCN production, which were expressed differentially at sub-optimal temperatures (5–40°C). It was
able to solubilize phosphate (17.7 μg ml−1), and produce IAA (139.7 μg ml−1) at 28 ± 2°C. Qualitative detection of siderophore production and HCN were also observed. At 5°C it was found to express
all the plant growth promotion attributes except HCN production. The ability to colonize roots is a sine qua non condition
for a rhizobacteria to be considered a true plant growth-promoting rhizobacteria (PGPR). Bacillus sp. NII-0902 has a potential ability to colonize roots visualized by transparency, bacterial growth (turbid, milky and narrow
zone) along and around roots and truly supported by scanning electron micrograph. Hence, it is proposed that, Bacillus thioparus sp. NII-0902 could be deployed as an inoculant to attain the desired results of bacterization. 相似文献
2.
S Ramadasappa AK Rai RS Jaat A Singh R Rai 《World journal of microbiology & biotechnology》2012,28(4):1681-1690
Tomato (Lycopersicon esculentum) is important widely grown vegetable in India and its productivity is affected by bacterial wilt disease infection caused
by Ralstonia solanacearum. To prevent this disease infection a study was conducted to isolate and screen effective plant growth promoting rhizobacteria
(PGPR) antagonistic to R. solanacearum. A total 297 antagonistic bacteria were isolated through dual culture inoculation technique, out of which forty-two antagonistic
bacteria were found positive for phlD gene by PCR amplification using two primer sets Phl2a:Phl2b and B2BF:BPR4. The genetic diversity of phlD
+ bacteria was studied by amplified 16S rDNA restriction analysis and demonstrated eleven groups at 65% similarity level. Out
of these 42 phlD
+ antagonistic isolates, twenty exhibited significantly fair plant growth promoting activities like phosphate solubilization
(0.92–5.33%), 25 produced indole acetic acid (1.63–7.78 μg ml−1) and few strains show production of antifungal metabolites (HCN and siderophore). The screening of PGPR (phlD
+) for suppression of bacterial wilt disease in glass house conditions was showed ten isolated phlD
+ bacteria were able to suppress infection of bacterial wilt disease in tomato plant (var. Arka vikas) in the presence R. solanacearum. The PGPR (phlD
+) isolates s188, s215 and s288 was observed to be effective plant growth promoter as it shows highest dry weight per plant
(3.86, 3.85 and 3.69 g plant−1 respectively). The complete absence of wilt disease symptoms in tomato crop plants was observed by these treatments compared
to negative control. Therefore inoculation of tomato plant with phlD
+ isolate s188 and other similar biocontrol agents may prove to be a positive strategy for checking wilt disease and thus improving
plant vigor. 相似文献
3.
A Gram positive, rod-shaped potential strain was selected from the pool of bacterial isolates obtained from the Western Ghats
forest (India) on the basis of zone of P-solubilization activity. Identification based on 16S rRNA gene sequence revealed
that the strain is of Bacillus species, sharing highest sequence similarity to Bacillus tequilensis NRRL B-41771T (99.5%). Strain NII-0943 was able to produce good amount of indole acetic acid (IAA) and was positive for siderophore production.
In addition to IAA and siderophore attributes, strain NII-0943 also possessed the characteristics like Ca3(PO4)2 solubilization and growth in nitrogen-free medium. Seed inoculation with the strain NII-0943 resulted in significantly higher
root initiation in black pepper cuttings grown under pots. The contents of nitrogen and phosphorus in both soil and plant
were also enhanced significantly in treatments inoculated with these bacterial inocula. Hence, based on this evidence it is
proposed that strain NII-0943 could be deployed as a plant growth-promoting inoculant to attain the desired results of bacterization. 相似文献
4.
Basharat Ali Anjum Nasim Sabri Shahida Hasnain 《World journal of microbiology & biotechnology》2010,26(8):1379-1384
Potential of non-symbiotic plant growth promoting rhizobacteria (PGPR) to influence the endogenous indole-3-acetic acid (IAA)
content and growth of Vigna radiata (L.) was evaluated. The bacterial strains used belonged to Pseudomonas, Escherichia, Micrococcus and Staphylococcus genera. All strains were able to produce IAA (1.16–8.22 μg ml−1) in the presence of 1,000 μg ml−1 of l-tryptophan as revealed by gas chromatography and mass spectrometric (GC–MS) analysis. However, strains exhibited variable
results for other growth promoting traits such as phosphate solubilization and siderophore or hydrogen cyanide production.
Bacterial IAA production showed significant positive correlation with endogenous IAA content of roots (r = 0.969; P = 0.01) and leaves (r = 0.905; P = 0.01) under axenic conditions. Bacterization of V. radiata seeds significantly enhanced shoot length (up to 48.10%) and shoot fresh biomass (up to 43.80%) under fully axenic conditions.
Bacterial strains applied under wire-house conditions also improved shoot length, number of pods, and grain weight up to 58,
65, and 17.15% respectively, over control. Hence, free living (non-symbiotic) PGPR have the ability to influence endogenous
IAA content and growth of leguminous plants. 相似文献
5.
G. Selvakumar S. Kundu Piyush Joshi Sehar Nazim A. D. Gupta H. S. Gupta 《Indian journal of microbiology》2010,50(1):50-56
Exiguobacterium acetylicum strain 1P (MTCC 8707) is a gram-positive, rod-shaped, yellow pigmented bacterium isolated from soil on nutrient agar plates
at 4°C. The identity of the bacterium was arrived on the basis of the biochemical characterization, BIOLOG sugar utilization
pattern and sequencing of the 16S rRNA gene. It grew at temperatures ranging from 4 to 42°C, with temperature optima at 30°C.
It expressed multiple plant growth promotion attributes such as phosphate solubilization, indole acetic acid (IAA), siderophore
and hydrogen cyanide (HCN) production, differentially at suboptimal growth temperatures (15 and 4°C). At 15°C it solubilized
phosphate (21.1 μg of P ml−1 day−1), and produced IAA (14.9 μg ml−1 day−1) in tryptophan amended media. Qualitative detection of siderophore production and HCN were possible at 15°C. At 4°C it retained
all the plant growth promotion attributes. Seed bacterization with the isolate, positively influenced the growth and nutrient
uptake parameters of wheat seedlings in glass house studies at suboptimal cold growing temperatures. 相似文献
6.
This study was undertaken to explore the role of Trichoderma sp. in phosphate (P) solubilization and antagonism against fungal phytopathogens. All fungal isolates (SE6, KT6, KT28, and BRT11) and a standard culture of T. harzianum (Th-std) were able to antagonize two fungal phytopathogens (Sclerotium rolfsii and Rhizoctonia solani) of chickpea (Cicer arietinum L.) wilt complex. Transmission electron microscopic studies (TEM) further confirmed ultra-cytological changes in the sclerotia
of S. rolfsii parasitized by Trichoderma sp. All fungal cultures exhibited production of NH3 and siderophore, but only BRT11, SE6, and Th-std could produce HCN. Among all the cultures tested, isolate KT6 was found to be most effective for solubilization of ferric phosphate releasing 398.4 μg ml−1 phosphate while isolates BRT11 and SE6 showed more potential for tricalcium phosphate (TCP) solubilization releasing 449.05 and 412.64 μg ml−1 phosphate, respectively, in their culture filtrates. Part of this study focused on the influence of abiotic stress conditions
such as pH, temperature, and heavy metal (cadmium) on phosphate (TCP) solubilizing efficiency. Two selected cultures KT6 and T. harzianum retained their P solubilizing potential at varying concentrations of cadmium (0–1000 μg ml−1). Isolate KT6 and standard culture of T. harzianum released 278.4 and 287.6 μg ml−1 phosphate, respectively, at 1000 μg ml−1cadmium. Maximum solubilization of TCP was obtained at alkaline pH and at 28°C temperature. Isolate BRT11 was found most alkalo-tolerant releasing 448.0 μg ml−1 phosphate at pH 9. 相似文献
7.
A phosphate solubilizing and antagonistic bacterial strain, isolated from a Western Ghat forest soil in Kerala province, India
(designated as NII-0906), showed cold tolerance and grew from 10 to 37°C (optimum temperature 30°C). It was a Gram-positive,
rod shaped, 0.8–1.6 μm in size, and exhibited tolerance to a wide pH range (5–12; optimum 7.0) and salt concentration up to
7% (w/v). The isolate showed maximum similarity with Exiguobacterium marinum TF-80T based on 16S rRNA analysis. It solubilized tricalcium phosphate under in vitro conditions. The phosphate solubilization was
estimated along a temperature range (5–40°C), and maximum activity (84.7 μg mL−1 day−1) was recorded at 30°C after 10 days of incubation. The phosphate solubilizing activity coincided with a concomitant decrease
in pH of the medium. The isolate also exhibited antifungal activity against phytopathogenic fungi in Petri dish assays and
produced siderophore and hydrogen cyanide. The strain’s plant growth promotion properties were demonstrated through a cowpea-based
bioassay under greenhouse conditions. The bacterial inoculation resulted in significant increment in plant root, stem and
as well as in plant biomass. Further, scanning electron microscopic study revealed the root colonization in cowpea. These
results could offer potential perspective for the strain to be used as plant growth-promoting rhizobacteria, which could be
used as an inoculant for regional crops. 相似文献
8.
This study was designed to identify rhizobial strains specific to greengram expressing higher tolerance against insecticides,
fipronil and pyriproxyfen, and synthesizing plant growth regulators even amid insecticide-stress. Of the 50 bradyrhizobial
isolates, the Bradyrhizobium sp. strain MRM6 showed tolerance up to 1,600 μg mL−1 against each of fipronil and pyriproxyfen. The tolerant Bradyrhizobium sp. (vigna) produced plant growth promoting substances in substantial amounts, both in the presence and absence of insecticides. The
strain MRM6 was further used to investigate its impact on greengram grown in soils treated with 200 (the recommended dose),
400 and 600 μg kg−1 soil of fipronil and 1,300 (the recommended dose), 2,600 and 3,900 μg kg−1 soil of pyriproxyfen. Fipronil at 600 μg kg−1 soils and pyriproxyfen at 3,900 μg kg−1 soils had greatest toxic effects and decreased plant biomass, symbiotic efficiency, nutrient uptake and seed yield of greengram
plants. The Bradyrhizobium sp. (vigna) inoculant when used with fipronil and pyriproxyfen significantly increased the measured parameters compared to the plants
grown in soils treated solely with the same concentration of each insecticide. This study inferred that the Bradyrhizobium sp. (vigna) strain MRM6 may be exploited as bio-inoculant to increase the productivity of greengram exposed to insecticide-stressed
soils. 相似文献
9.
Tarun Kumar Verinder Wahla Piyush Pandey R. C. Dubey D. K. Maheshwari 《World journal of microbiology & biotechnology》2009,25(2):277-285
Biological control of the cyst forming nematode Heterodera cajani was studied on sesame using plant growth promoting rhizobacteria (PGPR) Pseudomonas aeruginosa LPT3 and LPT5. Based on plant growth promoting attributes, two fluorescent pseudomonads, LPT3 and LPT5 were evaluated for
their efficacy against cyst forming nematode Heterodera cajani that parasitize Sesamum indicum. Pseudomonas aeruginosa LPT5 produced IAA, HCN, chitinase, glucanase and siderophore, and also solubilized inorganic phosphate in vitro. Moreover,
LPT5 resulted in mortality of second stage juveniles of H. cajani, which was 13% higher as compared to P. aeruginosa LPT3. Interestingly, when both strains were inoculated together for the management of H. cajani on Sesamum indicum the population of H. cajani was reduced significantly, in field trial. Approximately 60% reduction in cyst and juveniles population was recorded with
LPT5 coated seeds, while LPT3 resulted in 49% reduction in cyst and juvenile population as compared to control. Plants grown
with seeds bacterized with LPT5 and reduced doses of urea, diammonium phosphate (DAP), muriate of potash (K) and gypsum gave
maximum increase in yield, in comparison to that of plants raised under the influence of recommended or full doses of the
chemical fertilizers. Pseudomonas aeruginosa LPT5 also showed excellent root colonization. 相似文献
10.
Salinity adversely affects plant growth and development. Halotolerant plant-growth-promoting rhizobacteria (PGPR) alleviate
salt stress and help plants to maintain better growth. In the present study, six PGPR strains were analyzed for their involvement
in salt-stress tolerance in Arachis hypogaea. Different growth parameters, electrolyte leakage, water content, biochemical properties, and ion content were analyzed in
the PGPR-inoculated plants under 100 mM NaCl. Three bacterial strains, namely, Brachybacterium
saurashtrense (JG-06), Brevibacterium
casei (JG-08), and Haererohalobacter (JG-11), showed the best growth of A. hypogaea seedlings under salt stress. Plant length, shoot length, root length, shoot dry weight, root dry weight, and total biomass
were significantly higher in inoculated plants compared to uninoculated plants. The PGPR-inoculated plants were quite healthy
and hydrated, whereas the uninoculated plant leaves were desiccated in the presence of 100 mM NaCl. The percentage water content
(PWC) in the shoots and roots was also significantly higher in inoculated plants compared to uninoculated plants. Proline
content and soluble sugars were significantly low, whereas amino acids were higher than in uninoculated plants. The MDA content
was higher in uninoculated plants than in inoculated plants at 100 mM NaCl. The inoculated plants also had a higher K+/Na+ ratio and higher Ca2+, phosphorus, and nitrogen content. The auxin concentration was higher in both shoot and root explants in the inoculated plants.
Therefore, it could be predicted that all these parameters cumulatively improve plant growth under saline conditions in the
presence of PGPR. This study shows that PGPR play an important role in inducing salinity tolerance in plants and can be used
to grow salt-sensitive crops in saline areas. 相似文献
11.
Zaki A. Siddiqui G. Baghel M. S. Akhtar 《World journal of microbiology & biotechnology》2007,23(3):435-441
Biocontrol of the root-knot nematode Meloidogyne javanica was studied on lentil using plant growth-promoting rhizobacteria (PGPR) namely Pseudomonas putida, P. alcaligenes, Paenibacillus polymyxa and Bacillus pumilus and root nodule bacterium Rhizobium sp. Pseudomonas putida caused greater inhibitory effect on the hatching and penetration of M. javanica followed by P. alcaligenes, P. polymyxa and B. pumilus. Inoculation of any PGPR species alone or together with Rhizobium increased plant growth both in M. javanica-inoculated and -uninoculated plants. Inoculation of Rhizobum caused greater increase in plant growth than caused by any species of plant growth-promoting rhizobacteria in nematode-inoculated
plants. Among PGPR, P. putida caused greater increase in plant growth and higher reduction in galling and nematode multiplication followed by P. alcaligenes, P. polymyxa and B. pumilus. Combined use of Rhizobium with any species of PGPR caused higher reduction in galling and nematode multiplication than their individual inoculation.
Use of Rhizobium plus P. putida caused maximum reduction in galling and nematode multiplication followed by Rhizobium plus P. alcaligens. Pseudomonas putida caused greater root colonization and siderophore production followed by P. alcaligenes, P. polymyxa and B. pumilus. Analysis of the protein bands of these four species by SDS-PAGE revealed that P. putida had a different protein band profile compared to the protein profiles of P. alcaligenes, P. polymyxa and B. pumilus. However, the protein profiles of P. acaligenes, P. polymyxa and B. pumilus were similar. 相似文献
12.
Fuhong Xie Yapeng Chao Zhiquan Xue Xiuqing Yang Guoqing Zhang Jiaji Shi Shijun Qian 《Journal of industrial microbiology & biotechnology》2009,36(5):739-746
In industry, fosfomycin is mainly prepared via chemical epoxidation of cis-propenylphosphonic acid (cPPA). The conversion yield of fosfomycin is less than 50% in the whole process and a large quantity
of waste is produced. Biotransformation by microorganisms is an alternative method of preparation. This kind of conversion
is more delicate, environmentally friendly, and the conversion yield of fosfomycin would be higher. In this work, an aerobic
bacterium capable of transforming cPPA to fosfomycin was isolated. The organism, designated as strain S101, was identified
as Bacillus simplex by morphological and physiological characteristics as well as by analysis of the gene encoding the 16S rRNA. Fosfomycin was
assayed by two means, bioassay and gas chromatography (GC). Glycerol was a good carbon source for growth and cPPA conversion
of strain S101. When cPPA was used as the sole carbon source, neither growth nor conversion to fosfomycin occurred. The optimum
cPPA concentration in the conversion medium was 2,000 μg ml−1. After 6 days of incubation, the concentration of fosfomycin reached its maximum level (1,838.2 μg ml−1), with a conversion ratio of 81.3%. Air was indispensable for the growth but not for the conversion to fosfomycin. Furthermore,
vanadium ions were found to be essential for the conversion. High concentrations of cPPA had fewer inhibitory effects on the
growth of strain S101. 相似文献
13.
Katarzyna Sykłowska-Baranek Agnieszka Pietrosiuk Anna Gawron Anna Kawiak Ewa Łojkowska Małgorzata Jeziorek Ioanna Chinou 《Plant Cell, Tissue and Organ Culture》2012,108(2):213-219
The effects of medium exchange and methyl jasmonate addition on growth and production of shikonin and its derivatives acetylshikonin
and isobutyrylshikonin in hairy root cultures of Lithospermum canescens were investigated. Responses varied depending on the transgenic line and stage of growth at which these lines were subjected
to treatment. Shikonin itself was not detected, irrespective of the transgenic line and culture treatment used. A eightfold
increase in acetylshikonin and isobutyrylshikonin accumulation was achieved when 32-day-old transgenic roots of Lc1D line
were transferred from LS to M9 medium for the subsequent 3 weeks of culture. Methyl jasmonate exerted a detrimental effect
on red naphthoquinones production. The extracts obtained from roots cultivated in M9 medium for 3 weeks were subjected to
a cytotoxicity assay and displayed cytotoxic activity against human promyelocytic leukemia cells (HL-60) at the dose of 4 μg ml−1. 相似文献
14.
Ping Su Anders Henriksson Christina Nilsson Hazel Mitchell 《World journal of microbiology & biotechnology》2008,24(9):1837-1842
The aim of this study was to assess the effect of a commercial green tea extract (TEAVIGO™) on the microbial growth of three
probiotic strains (Lactobacillus and Bifidobacterium), as well as three pathogenic bacteria. MIC and co-culture studies were performed. The MICs of the green tea extract against
Staphylococcus aureus and Streptococcus pyogenes (100 μg ml−1) were considerably lower than those against the probiotic strains tested (>800 μg ml−1) and Escherichia coli (800 μg ml−1). In co-culture studies, a synergistic effect of the probiotic strains and the green tea extract was observed against both
Staph. aureus and Strep. pyogenes. Green tea extract in combination with probiotics significantly reduced the viable count of both pathogens at 4 h and by
24 h had completely abolished the recovery of viable Staph. aureus and Strep. pyogenes. These reductions were more significant than the reductions induced by probiotics or green tea extracts used separately.
These results demonstrate the potential for combined therapy using the green tea extract plus probiotics on microbial infections
caused by Staph. aureus and Strep. pyogenes. As probiotics and the green tea extract are derived from natural products, treatment with these agents may represent important
adjuncts to, or alternatives to, conventional antibiotic therapy. 相似文献
15.
Byung Kwon Jung Abdur Rahim Khan Sung-Jun Hong Gun-Seok Park Yeong-Jun Park Ho-Jin Kim Hwang-Ju Jeon Muhammad Aaqil Khan Muhammad Waqas In-Jung Lee Sung-Eun Lee Jae-Ho Shin 《Annals of microbiology》2017,67(9):623-632
Plant growth-promoting rhizobacteria (PGPR) affect plant growth through various mechanisms, such as indole-3-acetic acid (IAA) production, 1-aminocyclopropane-1-carboxylic acid (ACC) deaminase activity, and biofilm formation. The aim of the study reported here was to isolate and characterize rhizobacteria that produce quorum-sensing signal molecules and other PGPR-related molecules. A biofilm-forming bacterium, GS2, was isolated from the rhizosphere of a sesame plant and subsequently found to produce two quorum-sensing signal molecules that were identified as N-hexanoyl-L-homoserine lactone (m/z 200) and N-octanoyl-L-homoserine lactone (m/z 228) by liquid chromatography–tandem mass spectrometry analysis. The strain was also found to produce IAA (17.2 μg mL?1), gibberellins (113.7 μg mL?1), and ACC deaminase (9.7 μM α-ketobutyrate mg?1 protein h?1). The strain was identified as Serratia glossinae based on a comparison of 16S rRNA gene sequences. Inoculation of the strain promoted growth of a gibberellin-deficient rice dwarf mutant (Waito-C). Different growth attributes, including shoot and root elongation, chlorophyll content, and plant weight could be attributed to the PGPR characteristics of strain GS2. These results suggest that S. glossinae strain GS2 can serve as a microbial agent that improves plant growth. 相似文献
16.
Abhishek Tripathi Neeta Sharma Vinay Sharma 《World journal of microbiology & biotechnology》2009,25(3):503-512
Hyptis
suaveolens L. (Poit.) essential oil was tested in vitro on the growth and morphogenesis of Fusarium oxysporum f.sp. gladioli (Massey) Snyder & Hansen, which causes Fusarium corm rot and yellows in various susceptible cultivars of gladiolus. The fungitoxicity of the oil was measured by percentage radial growth inhibition using the poisoned food technique (PF)
and volatile activity assay (VA). The mycelial growth of the test fungus was completely inhibited at 0.998 and 0.748 μg ml−1 concentration of oil in PF and VA, respectively. Essential oil was found to be fungicidal in nature at 1.247 and 0.998 μg ml−1 concentration of oil in PF and VA, respectively. Determination of conidial germination in the presence of oil was also carried
out and it was found that the oil exhibited 100% inhibition of conidial germination at 0.450 μg ml−1 concentration. The effect of essential oil on the yield of mycelial weight was observed and it was found that at 0.873 μg ml−1 concentration no mycelium was recorded and 100% inhibition was observed. The fungitoxicity of oil did not change even on
exposure to 100°C temperature or to autoclaving, and the oil also retained its fungicidal nature even after storage of 24 months.
The main changes observed under light microscopy after oil treatment were a decrease and loss of conidiation and anomalies
in the hyphae such as a decrease in the diameter of hyphae and granulation of cytoplasm. The treatment of the oil also showed
highly reduced cytoplasm in the hyphae, showing clear retraction of the cytoplasm from the hyphae and ultimately in some areas
hyphae without cytoplasm were also found. GC-MS studies of the essential oil revealed that the oil consisted of 24 compounds
with 1,8-cineole as major component accounting for 44.4% of the total constituents. 相似文献
17.
DC Sabaté MJ Gonzaléz MP Porrini MJ Eguaras MC Audisio JM Marioli 《World journal of microbiology & biotechnology》2012,28(4):1415-1422
The aim of this work was to determine the in vitro effect of the mixture between the lipopeptide surfactin, synthesized by
Bacillus subtilis C4 (strain isolated from honey) and the most active vegetal extract from Achyrocline satureioides, a traditional medicinal plant, on local strains of Paenibacillus larvae, the agent of American Foulbrood in honeybees. Five P. larvae strains isolated in Córdoba, Argentina, were phenotypically characterized. These and 12 other P. larvae strains from different regions of Argentina were analysed. The antimicrobial activities of the essential oil, hexane (HE)
and benzene extracts from A. satureioides were assessed against P. larvae and the HE showed the highest anti-P. larvae activity. A combination of the biosurfactant surfactin, produced by B. subtilis C4, and the HE of A. satureioides revealed a synergistic action on P. larvae. The effective surfactin concentration in the mixture decreased from 32 to 1 μg ml−1 and the HE concentration from 32 to 4 μg ml−1, values similar or equal to minimal inhibitory concentrations observed for oxytetracycline. The fractional inhibitory concentration
index confirmed synergism in 4 strains and partial synergism in one strain. The combination of surfactin synthesized by B. subtilis C4 and the HE from A. satureioides could be a natural alternative to help beekeepers to combat the American foulbrood agent P. larvae. 相似文献
18.
19.
Basharat Ali Anjum Nasim Sabri Karin Ljung Shahida Hasnain 《World journal of microbiology & biotechnology》2009,25(3):519-526
Sixteen Bacillus strains isolated from rhizosphere, histoplane and phyllosphere of different plant species were identified by 16S rDNA gene
sequencing and evaluated for in vitro auxin production as well as growth stimulation of Vigna radiata (L.) Wilczek. Auxin production by Bacillus spp. in L-broth medium supplemented with 1,000 μg ml−1
L-tryptophan ranges from 0.60 to 3.0 μg IAA ml−1 as revealed by gas chromatography and mass spectrometric (GC–MS) analysis. Rhizospheric isolates exhibit relatively more
IAA synthesis than histoplane and phyllosphere isolates. Plant microbe interaction experiments conducted under gnotobiotic
conditions recorded 55.55, 46.46 and 46.20% increase in shoot length with Bacillus megaterium MiR-4, B. pumilus NpR-1 and B. subtilis TpP-1, respectively, over control. Bacillus inoculations also increased shoot fresh weight with B. megaterium MiR-4 (60.94%) and B. pumilus NpR-1 (37.76%). Highly significant positive correlation between auxin production analyzed by GC–MS and shoot length (r = 0.687**, P = 0.01) and shoot fresh weight (r = 0.703**, P = 0.01) was noted under gnotobiotic conditions. Similarly, significant correlation was also found between auxin production
by Bacillus spp. (GC–MS analysis) and different growth parameters such as shoot length (r = 0.495*, P = 0.05), number of pods (r = 0.498*, P = 0.05) and grain weight (r = 0.537*, P = 0.05) at full maturity under natural wire house conditions. Results showed that auxin production potential of plant associated
Bacillus spp. can be effectively exploited to enhance the growth and yield of V. radiata. 相似文献
20.
F. D. Espasandin M. M. Collavino C. V. Luna R. C. Paz J. R. Tarragó O. A. Ruiz L. A. Mroginski P. A. Sansberro 《Plant Cell, Tissue and Organ Culture》2010,102(2):181-189
A protocol for the production of transgenic plants was developed for Lotus tenuis via Agrobacterium-mediated transformation of leaf segments. The explants were co-cultivated (for 3 days) with an A. tumefaciens strain harbouring either the binary vector pBi RD29A:oat arginine decarboxylase (ADC) or pBi RD29A:glucuronidase (GUS), which
carries the neomycin phosphotransferase II (nptII) gene in the T-DNA region. Following co-cultivation, the explants were cultured in Murashige and Skoog medium supplemented
with naphthalenacetic acid (NAA) and benzyladenine (BA) and containing kanamycin (30 μg ml−1) and cefotaxime (400 μg ml−1) for 45 days. The explants were subcultured several times (at 2-week intervals) to maintain the selection pressure during
the entire period. About 40% of the explants inoculated with the pBiRD29:ADC strain produced eight to ten adventitious shoots
per responsive explant through a direct system of regeneration, whereas 69% of the explants inoculated with the pBi RD29A:GUS
strain produced 13–15 adventitious shoots per responsive explant. The selected transgenic lines were identified by PCR and
Southern blot analysis. Three ADC transgenic lines were obtained from 30 infected explants, whereas 29 GUS transgenic lines
were obtained from 160 explants, corresponding to a transformation efficiency of 10 and 18.1%, respectively. More than 90%
of the in vitro plantlets were successfully transferred to the soil. The increase in the activity of arginine decarboxylase
from stressed ADC- Lt19 lines was accompanied by a significant rise in the putrescine level. The GUS transgenic line driven by the RD29A promoter
showed strong signals of osmotic stress in the leaves and stem tissues. All of the transgenic plants obtained exhibited the
same phenotype as the untransformed controls under non-stress conditions, and the stability of the gene introduced into the
cloned materials was established. 相似文献