Javid A. Parray

Current Perspectives on Plant Growth-Promoting Rhizobacteria

The rhizosphere of plant species is an inimitable ecosystem that harbors an extensive range of microbes. Research in the wide areas of rhizosphere biotechnology highlighting new bioinoculants has received ample attention during recent past, and suitable expertises have been developed. However, the global recognition of such technologies by farmers is still overwhelmed with doubts owing to limited shelf-life and efficiency of the products which demonstrate discrepancies. This review illustrates plant growth-promoting rhizobacteria with detailed emphasis on nutrient acquisition and potential roles in conferring tolerance against abiotic stresses. The review demonstrates the recent research in the field of genomic and proteomic analysis, where systematic characterization of potentially effective rhizobacteria is being carried out by screening the extensive bacterial gene pool based on modern molecular tools. The review concludes by emphasizing the efforts made in the proteomics field which could compensate for understanding of prompt evolution in microbe-derived and plant-derived protein and metabolite substitute that activates vulnerability or resistance.

Antibacterial and antioxidant activity of methanol extracts of Crocus sativus L. c.v. Kashmirianus

In this study, we investigated the antibacterial and antioxidant activities of Crocus sativus L. Kashmirianus c.v. extracts (callus and stigmas). Profuse callus was obtained on MS medium enriched with BAP (20 μ M)+NAA (15 μ M) under in vitro conditions from corm slices. Four pathogenic bacterial strains (Staphylococcus aureus CD0001, Escherichia coli CD0006, Pseudomonas aeruginosa CD0023 and Shigella flexneri CD0033) were used for determining the antibacterial activity of extracts. The antioxidant activity was determined by DPPH assay, DNA protection assay, FTC method, TBA assay and lipid peroxidation assay. The methanol stigma extract of saffron was found to be more effective in inhibiting all the pathogenic strains. The stigma extract also showed significant radical scavenging or chelation capacities in four of the methods; however, callus extract exhibited maximum inhibition of peroxy- radicals in lipid peroxidation assay. The protocol for callus production is described. It was concluded that as well as the specific parts of plants displaying diverse pharmacological activities, callus produced under in vitro conditions will assist in enhancing the production of secondary metabolites, which will reduce the pressure on natural saffron.

In vitro cormlet production of saffron (Crocus sativus L. Kashmirianus) and their flowering response under greenhouse

A complete protocol for the saffron cormlet production under in vitro conditions and subsequent flowering under greenhouse conditions is described. Highest number of cormlets (70.0 ± 0.30) per corm slice (explant) could be regenerated on Murashige and Skoog (MS) half strength medium supplemented with thidiazuron (TDZ) (20 µM), Indole acetic acid (IAA) (10 µM), and sucrose (40 g/l). Maximum germination (90%) of these cormlets could be achieved on MS medium containing 6-benzyl amino purine (BAP) (20 µM) and α-naphthalene acetic acid (NAA) (15 µM). In order to increase the size of the in vitro raised cormlets, these were cultured on MS medium containing TDZ (15 µM) and IAA in the range of 1.5-30 µM. Maximum increase in cormlet size could be attained on TDZ (15 µM) + IAA (12.5 µM) + sucrose (30 g/l), and the average size of cormlets was 2.5g. In another experiment, apical vegetative buds of actively growing corms were cultured for cormlet development, and corms of size 2.5g could be developed on MS medium with NAA (15 µM), BAP (20 µM), and sucrose (30 g/l). The in vitro developed cormlets were dried under shade at 25 ± 2°C for 7 d. These were then planted in small cups containing clay loam soil and kept in green house at 20 ± 2°C. In vitro developed cormlets with mean weight 2.5 g showed maximum flowering (25%) as well as vegetative growth (55%), while only 19% cormlets of 2.0 g flowered. To our knowledge this is the first report on successful flowering from in vitro raised cormlets under greenhouse.

Phytoremediation: A Green Technology

Phytoremediation is a lucrative plant-based advancement to remediation that takes lead in its knack to degrade environmental contaminants and to metabolize diverse pollutants. Heavy metals and organic pollutants are the central candidates for phytoremediation. To eliminate contaminants from soil, sediment, and/or water, plants can degrade organic pollutants or restrain and alleviate metal pollutants by substituting as filters or traps. Plants are exclusive organisms fitted with significant metabolic and absorption competence, plus transport systems that translocate nutrients or pollutants exclusively from the growth milieu, soil, or water. An in-depth perceptive of the physiological and molecular process of phytoremediation emerged as an efficient biological and engineering stratagem intended to optimize and enhance the prospective of phytoremediation process. Besides, various field experiments established the viability of using plants for cleaner environment. Metal-contaminated waters and soils are a main ecological crisis, and the majority of conventional remediation methods do not present adequate exposition. Utilization of genetically tailored plants is particularly selected for more efficient phytoremediation. In this chapter, we will illustrate numerous biological processes of heavy metal uptake, translocation, and resistance plus approaches for enhancing phytoremediation potential. Commercialization of bioremediation via genetically engineered microbes is contorted by debate over the expertise; transgenic plants may take center stage for environmental cleanup.

Approaches to Heavy Metal Tolerance in Plants

Phytoremediation is a lucrative plant-based advancement to remediation that takes lead in its knack to degrade environmental contaminants and to metabolize diverse pollutants. Heavy metals and organic pollutants are the central candidates for phytoremediation. To eliminate contaminants from soil, sediment, and/or water, plants can degrade organic pollutants or restrain and alleviate metal pollutants by substituting as fi lters or traps. Plants are exclusive organisms fi tted with signifi cant metabolic and absorption competence, plus transport systems that translocate nutrients or pollutants exclusively from the growth milieu, soil, or water. An in-depth perceptive of the physiological and molecular process of phytoremediation emerged as an effi cient biological and engineering stratagem intended to optimize and enhance the prospective of phytoremediation process. Besides, various fi eld

Differential response of terpenes and anthraquinones derivatives in Rumex dentatus and Lavandula officinalis to harsh winters across north-western Himalaya

Herbs adapted to diverse climates exhibit distinct variability to fluctuating temperatures and demonstrate various metabolic and physiological adaptations to harsh environments. In this research, Rumex dentatus L. and Lavandula officinalis L. were collected before snowfall in September–November to evaluate variability in major phytoconstituents to diverse seasonal regime. LC-MS was used for simultaneous determination of eight anthraquinone derivatives in R. dentatus, i.e. emodin, physcion, chrysophanol, physcion glucoside, endocrocin, emodin glucoside, chrysophanol glucoside and chromone derivatives and monoterpenes in L. officinalis i.e. (Z)-β-ocimene, (E)-β-ocimene, terpene alcohol, terpin-4-ol, acetate ester-linalyl acetate and bicyclic sesquiterpene (E)-caryophyllene. The correlation analysis confirmed significant variation in anthraquinone glucoside and terpene content within Rumex and Lavender, respectively, and altitude was established as the determinant factor in secondary metabolism of both herbs. The study concludes the propagation of herbs in bioclimatic belts which favour accumulation of major constituents and validate their greater pharmacological activity.

Variation in adaptation mechanisms of medicinal herbs to the extreme winter conditions across the North Western Himalaya

The North Western Himalaya region is characterized by extreme seasonal variability and local changes in microclimate. Plants adapted to this region demonstrate marked variability to the extreme winter conditions. This region, designated as a biodiversity hotspot, is rich in medicinal herbs, which exhibit diverse growth and adaptation mechanisms to the harsh environment. In the present study, physiological mechanisms of adaptation to the winter season conditions were compared in five medicinal herbs. Components of the photosynthetic machinery, and osmoregulation which are of importance for secondary metabolism is not well known in these alpine herbs and was studied. The medicinal herbs Rumex dentatus, Atropa accuminata, Lupinus polyphyllus, Hyoscyamus niger, and Lavandula officinalis were collected before snowfall in September–November to evaluate variability in metabolic and physiological responses to the varied seasonal regimes. Plants were followed over a period of 8 weeks (summer to early winter) in th...

Screening of beneficial properties of rhizobacteria isolated from Saffron (Crocus sativus L) rhizosphere

Plant growth promoting rhizobacterias (PGPRs) are free living soil bacteria that colonize root surfaces and have the capacity to enhance plant growth directly or indirectly. A total of 23 bacterial strains were isolated from saffron rhizoshere soil during the flowering stage of corms. All these isolates were screened for their plant growth promoting traits like production of IAA, phosphate solubilisation activity and siderophore production. The maximum percentage of the bacterial isolates was of Gram negative rod shaped type. A total of six isolates were capable of showing one or more than one of the activities like IAA production, Siderphore production and phosphate solubilisation activity. The Bacillus subtilis showed highest IAA production of 360 µg/ml while as Pseudomonas ssp., was found to be highly efficient in terms of phosphate solubilisation production (460 µg/ml) and siderophore production (62%). It was concluded from the results that these rhizobacterial strains isolated could be a promising source for plant growth promoting agent in increasing the growth of cormlets vis a vis enhancing the yield of saffron.

Aquatic bacterial diversity: Magnitude, dynamics, and controlling factors

The primary aspiration in the microbial observatory is to advance the understanding of freshwater bacterioplankton, whose diversity and population dynamics are currently the least understood off all freshwater planktonic organisms. Through identification and characterization of bacterial populations in a suite of fresh water bodies, we are able to gain significant new insight into the ecological niches of bacteria in diverse freshwater ecosystems. Given the facts that lakes and other inland freshwaters play a more critical role in the global carbon budget and that lakes have been described as early indicators of both regional and global environmental change, the role of microbes in these processes is of renewed interest. In this review, general overview will be given highlighting the characteristic features of bacterial species thriving in different water bodies. In the following sections, different cultural approaches vis a vis the controlling factors of bacterial diversity have been elaborated. In the concluding sections, the prospects of aquatic microbial diversity are well mentioned.

Emergence of multi drug resistance among soil bacteria exposing to insecticides.

Impacts of pesticide exposure on the soil microbial flora and cross resistance to antibiotics have not been well documented. Development of antibiotic resistance is a common issue among soil bacteria which are exposing to pesticides continuously at sub-lethal concentration. The present study was focused to evaluate the correlation between pesticide exposures and evolution of multi drug resistance among isolates collected from soil applied with insecticides. Twenty five insecticide (Monochrotophos) degrading bacteria were isolated from contaminated agricultural soil. The bacterial isolates Bacillus Sps, Bacillus cereus, Bacillus firmus and Bacillus thuringiensis were found to be resistant against chloramphenical, monochrotophos, ampicillin, cefotaxime, streptomycin and tetracycline antibiotics used. Involvement of plasmid in drug as well as insecticide resistant was confirmed through plasmid curing among selected bacterial strains. Bacillus Sps (MK-07), Bacillus cereus (MK-11), Bacillus firmus (MK-13) and Bacillus thuringiensis (MK-24) lost their resistant against insecticides and antibiotics once after removal of plasmid by exposing to 2% sodium dodecyl sulphate. The plasmid was transformed back to bacteria which produced similar derivatives when cultured in Minimal Salt medium (pH 7.0) supplemented with 0.4% of insecticide. Homology modeling was used to prove that organophosphorus hydrolase and able to metabolize all the antibiotics showed positive interaction with high docking score. The present study revealed that persistent of insecticides in the agricultural soil may lead to increasing development of multidrug resistance among soil bacteria.