Multifarious Plant Growth-Promoting Rhizobacterium Enterobacter sp. CM94-Mediated Systemic Tolerance and Growth Promotion of Chickpea (Cicer arietinum L.) under Salinity Stress

BACKGROUND

Chickpea is one of the most important leguminous crops and its productivity is significantly affected by salinity stress. The use of ecofriendly, salt-tolerant, plant growth-promoting rhizobacteria (PGPR) as a bioinoculant can be very effective in mitigating salinity stress in crop plants. In the present study, we explored, characterized, and evaluated a potential PGPR isolate for improving chickpea growth under salt stress.

METHODS

A potential PGPR was isolated from rhizospheric soils of chickpea plants grown in the salt-affected area of eastern Uttar Pradesh, India. The isolate was screened for salt tolerance and characterized for its metabolic potential and different plant growth-promoting attributes. Further, the potential of the isolate to promote chickpea growth under different salt concentrations was determined by a greenhouse experiment.

RESULTS

A rhizobacteria isolate, CM94, which could tolerate a NaCl concentration of up to 8% was selected for this study. Based on the BIOLOG carbon source utilization, isolate CM94 was metabolically versatile and able to produce multiple plant growth-promoting attributes, such as indole acetic acid, 1-aminocyclopropane-1-carboxylic acid (ACC) deaminase, siderophore, hydrogen cyanide (HCN), and ammonia as well as solubilized phosphate. A polyphasic approach involving the analysis of fatty acid methyl ester (FAME) and 16S rRNA gene sequencing confirmed the identity of the isolate as Enterobacter sp. The results of greenhouse experiments revealed that isolate CM94 inoculation significantly enhanced the shoot length, root length, and fresh and dry weight of chickpea plants, under variable salinity stress. In addition, inoculation improved the chlorophyll, proline, sugar, and protein content in the tissues of the plant, while lowering lipid peroxidation. Furthermore, isolate CM94 reduced oxidative stress by enhancing the enzymatic activities of superoxide dismutase, catalase, and peroxidase compared to in the respective uninoculated plants.

CONCLUSIONS

Overall, the results suggested that using Enterobacter sp. CM94 could significantly mitigate salinity stress and enhance chickpea growth under saline conditions. Such studies will be helpful in identifying efficient microorganisms to alleviate salinity stress, which in turn will help, to devise ecofriendly microbial technologies.

Phytochemical investigation of natural and in vitro raised Vṛddhadāruka plants

Background:

Argyreia nervosa commonly known as elephant creeper (English) and Vṛddhadāruka (Sanskrit) is a woody climber that belongs to the family Convolvulaceae. Seeds of this plant contain hallucinogens including ergot alkaloids and a naturally occurring lysergic acid amide. Traditionally the plant is used in the treatment of gonorrhea, strangury, chronic ulcers, diabetes, anemia and cerebral disorders. The plant is also used as appetitiser, brain tonic, cardiotonic, aphrodisiac. It possesses anti-inflammatory, immunomodulatory, antibacterial, antiviral and antifungal activities.

Objective:

To give an account of information on in vitro regeneration and phytochemical analysis of the plant.

Materials and Methods:

Nodal explants were selected for in vitro regeneration. Different aerial parts viz., seeds, natural and in vitro leaf, stem and callus were dried and extracted with different solvents and were subjected to various phytochemical analyses.

Results:

Different concentrations of 6-benzylaminopurine showed shoot and root initiation. The study of phytochemical screening of different extracts showed the presence of bioactive substances like flavonoids, alkaloids, terpenoids, etc.

Conclusion:

The study will provide an efficient in vitro protocol for micropropagation as an alternative method to conserve the plant and shows the presence of some important secondary metabolites in the nature grown and in vitro raised plants which can be useful for treatment of various diseases.

Recent patents on flavonoids

Flavonoids are substances which are widely distributed in the plant kingdom. They occur in considerable quantities in common food products, spices and beverages. Interest of researchers has been greatly enhanced towards therapeutic potential of flavonoids in last some years. This review summarizes important patents pertaining to recent biotechnological techniques applied for the production, analysis of biosynthetic pathways, effects and applications of different flavonoids. For systematic studies investigations which have been published in the form of patents, are classified in different sectors like biosynthesis, medical application, antimicrobial activity, alteration of flower color, industrial application, cosmetics, food and plant tissue culture. A number of activities have been observed in each sector with vast area of research on flavonoids.

Induction of somatic embryogenesis in endangered butterfly ginger Hedychium coronarium J. Koenig

An efficient protocol has been developed for regeneration of complete plants through somatic embryogenesis in H. coronarium. Creamish white, pale yellow and brown calli were obtained on MS medium supplemented with different concentrations of auxins [2, 4-Dichlorophenoxy acetic acid (2, 4-D), Indole-3 acetic acid (IAA) and 1-Naphthylacetic acid (NAA)] after 4 weeks. Creamy white calli developed on 0.5 mg L(-1) 2, 4-D turned embryogenic when subcultured on basal medium and produced small globular somatic embryos after 6 weeks. Further growth of somatic embryos required their transfer to medium containing 6-benzylaminopurine (BAP) or kinetin (KN). BAP was more effective than KN in promoting shoot proliferation. Maximum shoot length was obtained with 0.5 mg L(-1) BAP whereas maximum shoot number was obtained with 1.0 mg L(-1) BAP. The plantlets thus formed were successfully hardened, and transferred to sand-soil and farm yard manure (1:1:1) with 95% survival.

Rapid, simple and sensitive high-performance liquid chromatographic method for detection and determination of acyclovir in human plasma and its use in bioavailability studies

A rapid, simple and sensitive reversed-phase high-performance liquid chromatographic (HPLC) method has been developed for the measurement of acyclovir concentrations in human plasma and its use in bioavailability studies is evaluated. Unchanged acyclovir has been quantified without the introduction of an internal standard using the present method. Human plasma proteins were selectively precipitated by the addition of 7% perchloric acid to spiked plasma samples or to the plasma samples obtained after acyclovir administration to human volunteers and the mixture was spun at 1000 g for 10 min. The supernatant was directly injected into a Novaflex C18 column and detected at 254 nm. The mobile phase consisted of octane sulfonic acid buffer (pH 2.5) and methanol (92:08). The limit of quantitation for acyclovir in plasma was 20 ng/ml, which enabled the determination of the area under the curve (AUC) more precisely, that is, it is much closer to its extrapolated value. The present method has been successfully applied to samples from bioavailability studies.