Microbes of the phytomicrobiome are associated with every plant tissue and, in combination with the plant form the holobiont. Plants regulate the composition and activity of their associated bacterial community carefully. These microbes provide a wide range of services and benefits to the plant; in return, the plant provides the microbial community with reduced carbon and other metabolites. Soils are generally a moist environment, rich in reduced carbon which supports extensive soil microbial communities. The rhizomicrobiome is of great importance to agriculture owing to the rich diversity of root exudates and plant cell debris that attract diverse and unique patterns of microbial colonization. Microbes of the rhizomicrobiome play key roles in nutrient acquisition and assimilation, improved soil texture, secreting, and modulating extracellular molecules such as hormones, secondary metabolites, antibiotics, and various signal compounds, all leading to enhancement of plant growth. The microbes and compounds they secrete constitute valuable biostimulants and play pivotal roles in modulating plant stress responses. Research has demonstrated that inoculating plants with plant-growth promoting rhizobacteria (PGPR) or treating plants with microbe-to-plant signal compounds can be an effective strategy to stimulate crop growth. Furthermore, these strategies can improve crop tolerance for the abiotic stresses (e.g., drought, heat, and salinity) likely to become more frequent as climate change conditions continue to develop. This discovery has resulted in multifunctional PGPR-based formulations for commercial agriculture, to minimize the use of synthetic fertilizers and agrochemicals. This review is an update about the role of PGPR in agriculture, from their collection to commercialization as low-cost commercial agricultural inputs. First, we introduce the concept and role of the phytomicrobiome and the agricultural context underlying food security in the 21st century. Next, mechanisms of plant growth promotion by PGPR are discussed, including signal exchange between plant roots and PGPR and how these relationships modulate plant abiotic stress responses via induced systemic resistance. On the application side, strategies are discussed to improve rhizosphere colonization by PGPR inoculants. The final sections of the paper describe the applications of PGPR in 21st century agriculture and the roadmap to commercialization of a PGPR-based technology.

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Plant Growth-Promoting Rhizobacteria: Context, Mechanisms of Action, and Roadmap to Commercialization of Biostimulants for Sustainable Agriculture.

Plant beneficial endophytic bacteria: Mechanisms, diversity, host range and genetic determinants

Lawsonia inermis L. (henna): ethnobotanical, phytochemical and pharmacological aspects.

Skin diseases have been of major concern recently due to their association with the Human Immunodeficiency Virus and Acquired Immunity Deficiency Syndrome (HIV/AIDS). The study area (northern Maputaland) has the highest HIV infection rate in South Africa, which made them more prone to a wide range of skin conditions. Fungal infections due to the hot climate and overcrowding households are common in this area, as well as burn accidents due to the use of wood as the major fuel for cooking. It is known that the lay people in this area depend on medicinal plants for their primary health care. However no survey has been done in northern Maputaland to document the medicinal plants used to treat various skin disorder. Interviews were undertaken at 80 homesteads, using structured questionnaires. The focus was on plants used for dermatological conditions and information regarding vernacular plant names, plant parts used, preparation (independently and in various combinations) and application was collected. A total of 87 lay people, both male (22%) and female (78%) were interviewed on their knowledge of medicinal plants used to treat disorders of the skin. Forty-seven plant species from 35 families were recorded in the present survey for the treatment of 11 different skin disorders including abscesses, acne, burns, boils, incisions, ringworm, rashes, shingles, sores, wounds and warts. When searching the most frequently used scientific databases (ScienceDirect, Scopus and Pubmed), nine plant species (Acacia burkei, Brachylaena discolor, Ozoroa engleri, Parinari capensis, subsp. capensis, Portulacaria afra, Sida pseudocordifolia, Solanum rigescens, Strychnos madagascariensis and Drimia delagoensis) were found to be recorded for the first time globally as a treatment for skin disorders. Fourteen plant combinations were used. Surprisingly, the application of enema’s was frequently mentioned. The preference of traditional medicine over allopathic medicine by most of the interviewees strengthens previous studies on the importance that traditional medicine can have in the primary health care system in this rural community. Studies to validate the potential of these plants independently and in their various combinations is underway to provide insight into the anti-infective role of each plant.

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Medicinal plants used for the treatment of various skin disorders by a rural community in northern Maputaland, South Africa

Plants harbor diverse bacterial communities, which play crucial roles in plant health and growth, in their rhizosphere, phyllosphere and endosphere. Tomato is an important model for studying plant-microbe interactions, but comparison of its associated bacterial community is still lacking. In this study, using Illumina sequencing of 16S rRNA amplicons, we characterized and compared the bacterial size and community from rootzone soil as well as the rhizosphere, phyllosphere and endosphere of roots, stems, leaves, fruits and seeds of tomato plants that were grown in greenhouse conditions. Habitat (soil, phyllospheric, and endophytic) structured the community. The bacterial communities from the soil-type samples (rootzone soil and rhizosphere) showed the highest richness and diversity. The lowest bacterial diversity occurred in the phyllospheric samples, while the lowest richness occurred in the endosphere. Among the endophytic samples, both bacterial diversity and richness varied in different tissues, with the highest values in roots. The most abundant phyla in the tomato-associated community was Proteobacteria, with the exception of the seeds and jelly, where both Proteobacteria and Firmicutes were dominant. At the genus level, the sequences of Pseudomonas and Acinetobacter were prevalent in the rhizosphere, and in the phyllosphere, more than 97% of the sequences were assigned to Acinetobacter. For the endophytes, Acinetobacter, Enterobacter, and Pseudomonas were the abundant genera in the roots, stems and leaves. In the fruits, the bacterial endophytes varied in different compartments, with Enterobacter being enriched in the pericarp and seeds, Acinetobacter in the placenta, and Weissella in the jelly. The present data provide a comprehensive description of the tomato-associated bacterial community and will be useful for better understanding plant-microbe interactions and selecting suitable bacterial taxa for tomato production.

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Bacterial communities in the rhizosphere, phyllosphere and endosphere of tomato plants.

Dodonaea viscosa, a wild and perennial shrub that can tolerate harsh environmental conditions, was used for the isolation of its endophytic bacteria and their potential was explored for the promotion of Canola growth. The bacteria identified through 16S rRNA gene sequencing, belonged to ten different genera namely Inquilinus, Xanthomonas, Pseudomonas, Rhizobium, Brevundimonas, Microbacterium, Bacillus, Streptomyces, Agrococcus and Stenotrophomonas. All the strains produced small amount of IAA (indole acetic acid) in the absence of tryptophan and comparatively more in the presence of tryptophan. All the bacterial strains were positive for ammonia production, cellulase and pectinase activity, but few of them showed phosphate solubilization, siderophore and hydrogen cyanide production. Only three strains showed ACC (1-aminocyclopropane-1-carboxylate) deaminase activity when tested using in-vitro enzyme assay. Members of genera Bacillus, Pseudomonas and Streptomyces showed positive chitinase, protease and antifungal activity against two phytopathogenic fungi Aspergillus niger and Fusarium oxysoprum, while members of Xanthomonas, Pseudomonas and Bacillus showed significant root elongation of Canola which could be related with their positive plant-growth-promoting (PGP) traits. Among the three plant growth promoting Bacillus strains, B. idriensis is never reported before for its PGP activities. These results showed the potential of Dodonaea viscosa endophytic bacteria as PGPBs, which in future can be further explored for their host range/molecular mechanisms.

Plant growth-promoting potential of endophytic bacteria isolated from roots of wild Dodonaea viscosa L.

The aim of this study was to conduct an ethnobotanical survey of North Western Punjab to identify medicinal plants traditionally used to treat skin infections and to determine their antimicrobial potential against skin-infecting pathogens. Methanolic extracts of selected plants were screened against Staphylococcus aureus, Escherichia coli, Pseudomonas aeruginosa and Candida albicans using the well diffusion method. Some plants are traditionally used in combination with other plants and chemicals like vinegar and olive oil. Therefore, antimicrobial screening was also done for these combinations in different proportions. Results showed that out of 12 studied plants, six showed inhibitory effect against Staphylococcus aureus and Candida albicans. Azadirachta indica and Mentha arvensis showed high antibacterial activity against Staphylococcus aureus with similar minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) values of 2.5 and 5mg/ml, respectively. Azadirachta indica, Cassia angustifolia, Phoenix dactylifera and Lawsonia inermis were found to be effective against the fungus Candida albicans, with MIC values of 0.625, 1.25, 0.625, 0.625 mg/ml and MBC values of 1.25, 2.5, 1.25 and 1.25 mg/ml, respectively. None of the plants showed antimicrobial activity against Escherichia coli and Pseudomonas aeruginosa. The results of the combination experiment demonstrated that antimicrobial activity exhibited by combinations of plant extracts and chemicals was imparted by chemicals like vinegar.

Screening of indigenous knowledge of herbal remedies for skin diseases among local communities of north west punjab, pakistan

Endophytic bacteria can provide a useful alternative to synthetic fertilizers to improve plant growth. Wild plants are little investigated as a source of growth promoting endophytic bacteria for commercial application to crops. In present study, endophytic bacteria were isolated from Cannabis sativa L. (hemp) using two different methods to examine their ability to promote canola growth. Besides direct isolation from the roots, endophytic bacteria were also selectively isolated from the rhizosphere of C. sativa using canola. Under gnotobiotic conditions, six bacteria from the selective isolation significantly improved canola root growth, as compared to the two bacteria isolated from direct method. Overall, three isolates performed distinctly well, namely, Pantoea vagans MOSEL-t13, Pseudomonas geniculata MOSEL-tnc1, and Serratia marcescens MOSEL-w2. These bacteria tolerated high salt concentrations and promoted canola growth under salt stress. Further, the isolated bacteria possessed plant growth promoting traits like IAA production, phosphate solubilization, and siderophore production. Most isolates produced plant cell-wall degrading enzymes, cellulase and pectinase. Some isolates were also effective in hindering the growth of two phytopathogenic fungi in dual culture assay, and displayed chitinase and protease activity. Paenibacillus sp. MOSEL-w13 displayed the greatest antifungal activity among all the isolates. Present findings conclude that wild plants can be a good source for isolating beneficial microbes, and validates the employed selective isolation for improved isolation of plant-beneficial endophytic bacteria.

Selective isolation and characterization of agriculturally beneficial endophytic bacteria from wild hemp using canola.

Syndromic ichthyosis is rare inherited disorders of cornification with varied disease complications. This disorder appears in seventeen subtypes associated with severe systematic manifestations along with medical, cosmetic and social problems. Syndromic ichthyosis with prominent hair abnormalities covers five major subtypes: Netherton syndrome, trichothiodystrophy, ichthyosis hypotrichosis syndrome, ichthyosis hypotrichosis sclerosing cholangitis and ichthyosis follicularis atrichia photophobia syndrome. These syndromes mostly prevail in high consanguinity states, with distinctive clinical features. The known pathogenic molecules involved in ichthyosis syndromes with prominent hair abnormalities include SPINK5, ERCC2, ERCC3, GTF2H5, MPLKIP, ST14, CLDN1 and MBTPS2. Despite underlying genetic origin, most of the health professionals solely rely on phenotypic expression of these disorders that leads to improper management of patients, hence making these patients living an orphanage life. After dermal features, association of other systems such as nervous system, skeletal system, hair abnormalities or liver problems may sometimes give clues for diagnosis but still leaving place for molecular screening for efficient diagnosis. In this paper, we have presented a review of ichthyosis syndrome with prominent hair abnormalities, with special emphasis on their updated genetic consequences and disease management. Additionally, we aim to update health professionals about the practice of molecular screening in ichthyosis syndromes for appropriate diagnosis and treatment.

Updated strategies for the management, pathogenesis and molecular genetics of different forms of ichthyosis syndromes with prominent hair abnormalities.

Imran Afzal

Papers

Plant beneficial endophytic bacteria: Mechanisms, diversity, host range and genetic determinants

Plant growth-promoting potential of endophytic bacteria isolated from roots of wild Dodonaea viscosa L.

Screening of indigenous knowledge of herbal remedies for skin diseases among local communities of north west punjab, pakistan

Selective isolation and characterization of agriculturally beneficial endophytic bacteria from wild hemp using canola.

Updated strategies for the management, pathogenesis and molecular genetics of different forms of ichthyosis syndromes with prominent hair abnormalities.