The ability to synthesize Indole-3-acetic acid (IAA) is widely associated with the plant growth promoting rhizobacteria (PGPR). The present work deals with isolation and characterization of such ...bacteria from the rhizosphere of medicinal plant Stevia rebaudiana and optimization of IAA production from its isolates. The optimization of IAA production was carried out at different pH and temperature with varied carbon and nitrogen sources of culture media. Out of different isolates obtained, three of them were screened as efficient PGPRs on the basis of different plant growth promoting attributes. Isolates CA1001 and CA2004 showed better production of IAA at pH 9 (91.7 µg ml−1) and at temperature 37 °C (81.7 µg ml−1). Dextrose (1%) was found to be the best carbon source for isolate CA1001 with 104 µg ml−1 IAA production. Isolate CA 2004 showed best production of IAA 36 µg ml−1 and 34 µg ml−1 at 1.5% and 1% Beef extract as nitrogen source respectively. Isolate CA 1001 showed 32 µg ml−1 IAA production at 0.5% nicotinic acid concentration. From the current study, CA1001 and CA2004 emerged as noble alternatives for IAA production further which also resulted in root and shoot biomass generation in crop plants, hence can be further used as bio-inoculants for plant growth promotion.
Phytoremediation is considered as a novel environmental friendly technology, which uses plants to remove or immobilize heavy metals. The use of metal-resistant plant growth-promoting bacteria (PGPB) ...constitutes an important technology for enhancing biomass production as well as tolerance of the plants to heavy metals. In this study, we isolated twenty seven (NF1-NF27) chromium resistant bacteria. The bacteria were tested for heavy metals (Cr, Zn, Cu, Ni, Pb and Co) resistance, Cr(VI) reduction and PGPB characters (phosphate solubilization, production of IAA and siderophores). The results showed that the bacterial isolates resist to heavy metals and reduce Cr(VI), with varying capabilities. 37.14% of the isolates have the capacity of solubilizing phosphate, 28.57% are able to produce siderophores and all isolates have the ability to produce IAA. Isolate NF2 that showed high heavy metal resistance and plant growth promotion characteristics was identified by 16S rDNA sequence analysis as a strain of Cellulosimicrobium sp.. Pot culture experiments conducted under greenhouse conditions showed that this strain was able to promote plant growth of alfalfa in control and in heavy metals (Cr, Zn and Cu) spiked soils and increased metal uptake by the plants. Thus, the potential of Cellulosimicrobium sp. for both bioremediation and plant growth promotion has significance in the management of environmental pollution.
•Phytomolecules act as reducing and stabilizing molecules for metal nanoparticles.•Various instrumental techniques to characterize nanoparticles were discussed.•Factors influencing bioreduction ...potential were highlighted.•Application of biosynthesized nanoparticles in different fields was discussed.
Nanoparticles exhibit unique properties that enable them to find potential applications in various fields. Accordingly, significant research attention is being given to the development of novel strategies for the synthesis of nanoparticles. Among these, biological route of nanoparticle synthesis has been portrayed as an efficient, low-cost and environmental friendly technique. Biological materials such as bacteria, fungi, yeast, algae and plant have been reported to possess high bioreduction ability to synthesize various size and shape of metallic nanoparticles. Of these biomaterials, this review focuses on plant-mediated biosynthesis of metallic nanoparticles. The biomolecules present in the plants such as terpenoids, flavones, ketones, aldehydes, proteins, amino acids, vitamins, alkaloids, tannins, phenolics, saponins, and polysaccharides play a vital role in reduction of metals. A systematic comparison of literature, based on the bioreduction capacity of various plant biomass/extract towards various metals under different experimental conditions, is also provided. Various instrumental techniques utilized to characterize nanoparticles are also discussed. Finally, this review also highlights the application of biosynthesized nanoparticles in different fields such as medicine, agriculture, catalytic, cosmetic and food. Thus, this article reviews the achievements and current status of plant-mediated biosynthesis, and hopes to provide insights into this exciting research frontier.
Polyphenol Oxidases (PPOs) catalyze the conversion of phenolic substrates to quinones, leading to the formation of dark-colored precipitates in fruits and vegetables. This process, known as enzymatic ...browning, is the cause of undesirable changes in organoleptic properties and the loss of nutritional quality in plant-derived products. In potato (
L.), PPOs are encoded by a multi-gene family with different expression patterns. Here, we have studied the application of the CRISPR/Cas9 system to induce mutations in the
gene in the tetraploid cultivar Desiree. We hypothesized that the specific editing of this target gene would result in a lower PPO activity in the tuber with the consequent reduction of the enzymatic browning. Ribonucleoprotein complexes (RNPs), formed by two sgRNAs and Cas9 nuclease, were transfected to potato protoplasts. Up to 68% of regenerated plants contained mutations in at least one allele of the target gene, while 24% of edited lines carried mutations in all four alleles. No off-target mutations were identified in other analyzed
genes. Mutations induced in the four alleles of
gene, led to lines with a reduction of up to 69% in tuber PPO activity and a reduction of 73% in enzymatic browning, compared to the control. Our results demonstrate that the CRISPR/Cas9 system can be applied to develop potato varieties with reduced enzymatic browning in tubers, by the specific editing of a single member of the
gene family.
Products of genome editing as the most promising "New Plant Breeding Technology" (NPBT) have made the transition from the lab to the market in a short time. Globally, research activities employing ...genome editing are constantly expanding and more and more plants with market-oriented traits are being developed, and companies have already released the first genome edited crops to the market. Few countries, most of which are located in the Americas, have adapted legislations to these technologies or released guidelines supporting the use of genome editing. Other countries are debating the path to come either because there is no clarity on the legal classification or due consensus is hampered by a renewed GMO debate. In recent years (2017-2020), eight countries have introduced guidelines clarifying the legal status of genome edited products and many of those are actively committed to international harmonization of their policies. In this publication we give an overview on the current and potentially future international regulatory environment and an update on plants derived by genome editing with market-oriented traits.
Medicinal plants have historically proven their value as a source of molecules with therapeutic potential, and nowadays still represent an important pool for the identification of novel drug leads. ...In the past decades, pharmaceutical industry focused mainly on libraries of synthetic compounds as drug discovery source. They are comparably easy to produce and resupply, and demonstrate good compatibility with established high throughput screening (HTS) platforms. However, at the same time there has been a declining trend in the number of new drugs reaching the market, raising renewed scientific interest in drug discovery from natural sources, despite of its known challenges. In this survey, a brief outline of historical development is provided together with a comprehensive overview of used approaches and recent developments relevant to plant-derived natural product drug discovery. Associated challenges and major strengths of natural product-based drug discovery are critically discussed. A snapshot of the advanced plant-derived natural products that are currently in actively recruiting clinical trials is also presented. Importantly, the transition of a natural compound from a “screening hit” through a “drug lead” to a “marketed drug” is associated with increasingly challenging demands for compound amount, which often cannot be met by re-isolation from the respective plant sources. In this regard, existing alternatives for resupply are also discussed, including different biotechnology approaches and total organic synthesis.
While the intrinsic complexity of natural product-based drug discovery necessitates highly integrated interdisciplinary approaches, the reviewed scientific developments, recent technological advances, and research trends clearly indicate that natural products will be among the most important sources of new drugs also in the future.
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Halophytes contain many secondary metabolites that can facilitate the capping and stabilizing of nanoparticles. Synthesis and optimization of zinc oxide nanoparticles from Phragmites karka were ...performed for the first time in this study to assess the salinity resilience of tomato seedlings in 100 mM NaCl using biotechnological applications and growth analysis. Response surface methodology and central composite design data revealed that ZnO NPs were stable at a 2:1 ratio of plant and salt concentration (pH of 6.5 at 37.5 °C). The peak obtained at 331 nm from UV–Vis spectroscopy confirmed the synthesis of ZnO NPs and these NPs have multiple functional groups. The chemical bond formation of the prepared ZnO NPs (assessed using FTIR and XRD) confirmed the crystalline structure of ZnO NPs that were derived from halophyte P. karka. The SEM images revealed that ZnO NPs have a particle size of 23.5 nm and are spherical, while DLS revealed the size (32.6 nm) and zeta-potential (−6.43 mV) of nanoparticles. Plants treated with ZnO NPs increase the overall tomato growth parameters under salt stress, including shoot length (3-fold), especially at T20 (50 mgL −1 ZnO NPs + 100 mM NaCl) treatment among all growth weeks. The number of leaves increased at T16 (20 mgL −1 ZnO NPs + 100 mM NaCl). The numbers of nodes and internodes were increased at T20 (50 mgL −1 ZnO NPs + 100 mM NaCl) in both parameters. Halophytic nanoparticles could be beneficial sources of biostimulants to improve salt resilience of tomato plants undergoing salt stress.
•Genome selection (GS) considers marker effects across the whole genome.•The use of high-density markers is one of the features of GS.•GS is based on two distinct and related groups: training and ...breeding populations.•Phenotyping is a key informant in GS to build up accuracy of statistical models.•GS may revolutionize plant and tree breeding practices.
Association analysis is used to measure relations between markers and quantitative trait loci (QTL). Their estimation ignores genes with small effects that trigger underpinning quantitative traits. By contrast, genome-wide selection estimates marker effects across the whole genome on the target population based on a prediction model developed in the training population (TP). Whole-genome prediction models estimate all marker effects in all loci and capture small QTL effects. Here, we review several genomic selection (GS) models with respect to both the prediction accuracy and genetic gain from selection. Phenotypic selection or marker-assisted breeding protocols can be replaced by selection, based on whole-genome predictions in which phenotyping updates the model to build up the prediction accuracy.
The present study was aimed at determining total phenolic and flavonoid contents and studying the antioxidant activity of ginger (Zingiber officinale Rosc.) rhizome and callus, 6-gingerol and ...6-shogaol and callus treated with elicitors. Petroleum ether (PE) and chloroform: methanol (1:1, v/v) (CM) extracts were prepared by maceration. Highest total phenolic content was obtained from the CM extract (60.34 ± 0.43 mg gallic acid/g) of rhizome while callus showed lower content detected in the CM extract (33.6 ± 0.07 mg gallic acid/g). Flavonoids were only detected in rhizome (CM extract 40.25 ± 0.21 mg quercetin/g). Both rhizome extracts exhibited good antioxidant activity with higher activity recorded in PE extract (IC50 value 8.29 ± 1.73 μg/mL). Callus extracts revealed lower antioxidant activity (IC50 value 1265.49 ± 59.9 μg/mL obtained from CM extract). 6-gingerol and 6-shogaol displayed high antioxidant activity in both assays with IC50 4.85 + 0.58DPPH and 5.35 ± 0.33ABTS μg/mL for the former and IC50 7.61 ± 0.81DPPH and IC50 7.05 ± 0.23ABTS μg/mL for the latter. Treatment of callus with elicitors showed significant (p < 0.05) effects in enhancing phenolic content and related antioxidant activity. The highest significant increase in phenolic content (37% and 34%) and antioxidant activity in DPPH assay (34% and 30%) was observed in callus treated with 100 mg/L yeast extract and 50 mg/L salicylic acid respectively. Therefore, studying the effect of the elicitation of ginger cultured tissues in phenolic accumulation would be of immense importance for pharmacological, cosmetic and agronomic industries.
ABSTRACTGene technologies, such as transgenesis and new breeding techniques (NBTs), expand the toolbox for plant breeding. Many countries in Africa, however, have long been seen as “slow adopters” of ...gene technologies for several reasons, one being the lack of, or overly restrictive, biosafety regulatory frameworks. This is sometimes attributed to the influence of the precautionary-oriented EU biosafety policies. This study analyses and compares the biosafety regulatory frameworks and their implementation in Kenya, Nigeria and Uganda, and in the EU member state Sweden. The focus is on (1) the structure of the biosafety regulatory frameworks including the scope of the legislation, (2) the duration and cost of regulatory authorization for field trials with genetically modified (GM) plants, and (3) the regulatory approach to NBT products, i.e. to what extent NBT products are subject to the provisions of the biosafety regulatory framework. The data was collected through studying relevant legal and policy documents as well as interviewing regulatory officers and researchers in the respective countries. We found that the regulatory procedures in the selected countries are relatively straightforward, while the costs and duration may present a challenge. The regulatory approach to NBT products differ between the selected African countries and Sweden, the latter which follows EU regulations. The results are discussed in terms of the impact the regulatory developments in these four jurisdictions may have on international R&D collaborations involving the use of gene technologies and we also weigh the results against the common conception that Europe exerts a heavy influence on African countries in this technology field.
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