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Interactions between microorganisms and host plants determine the growth and development as well as the health of the host plant. Various microbial groups inhabit the rhizosphere, each with its peculiar function. The survival of each microbial group depends to a large extent on its ability to colonize the plant root and outcompete the native organisms. The role of the rhizospheric microbiome in enhancing plant growth has not been fully maximized. An understanding of the complexities of microbial interactions and factors affecting their assembly in the community is necessary to benefit maximally from the cooperations of various microbial communities for sustainable crop production. In this review, we outline the various organisms associated with the plant rhizosphere with emphasis on their interactions and mechanisms used in plant growth promotion.

Purpose Phyto-active components of Zanthoxylum zanthoxyloides and Gongronema latifolium was investigated against microbial contaminants in water for possible novel antimicrobial usage in water treatment. Method Crude ethyl acetate and chloroform fractions of Zanthoxylum zanthoxyloides and Gongronema latifolium were prepared and screened for antimicrobial and phytochemical profiles using standard methods. Results Crude extracts of the different plant examined selectively comprised saponins, tannins, reducing sugars, anthraquinones, flavonoids, terpenoids, phlobatanins and alkaloids. All plant extracts showed broad spectrum antibiosis against E. coli, P. aeruginosa, Klebsiella sp, S. pneumoniae and B. cereus, as well as A. niger, A. flavus, Trichoderma sp and Candida sp. Chloroform extracts compared well than ethyl acetate extracts. Conclusion This work represents the first report to direct the possible application of Zanthoxylum zanthoxyloides and Gongronema latifolium to potential application in water. Overall results revealed that antimicrobial activities are dose and plant dependent. Noteworthy is the comparatively greater antimicrobial activity of crude extracts over commercial antibiotics used at the concentration of extracts tested. These plants can therefore serve as a potent source of natural water disinfectant.

Phytochemical screening and antimicrobial analysis of Moringa oleifera leaf collected from Ogbomoso, Nigeria were carried out. The secondary metabolites in M. oleifera leaf were extracted by macera...

Background: The present study was designed to evaluate the phytochemicals of Terminalia glaucescens stem extracts and test their antimicrobial potency against water microbial contaminants reported to be multidrug resistant. Method: Dry stem powder was extracted with ethanol, ethyl acetate and chloroform. These fractions were then examined for antimicrobial activity by using disc diffusion assay against typical clinical bacteria and fungal isolates which have been reported as water contaminants. The microbial strains were exposed to five different concentrations of extracts: 500 mg/ml, 250 mg/ml, 100 mg/ml, 50 mg/ml and 25 mg/ml. Result: It was observed in this study that increase in the concentration of extracts correlated with microbial growth inhibition. In-vitro phytochemical screening of plant extracts revealed the presence of alkaloid, flavonoid, saponin, terpenoid, steroid and anthraquinones. Ethanolic extract performs better than ethyl acetate and chloroform extracts, as it recorded the highest zone of inhibition of 20.5 mm against Streptococcus pneumoniae while ethyl acetate and chloroform recorded 17.50 mm each against Streptococcus pneumoniae and Bacillus cereus, respectively. Ethanolic extract also showed the highest antifungal activity against Trichoderma sp. and Aspergillus niger. The antibacterial and antifungal activities of active extracts were observed in the increasing order Ethanol>Chloroform≥ethyl acetate with respect to the maximum zone of inhibition. Activity of crude extract from ethanol, when further compared with commercial antibiotics (Gentamicin, Streptomycin and Nystatin), was significantly higher. Conclusion: This plant crude extracts could therefore serve as potential source of new biocides with application in water research and other biotechnological fields.

The persistent and undiscriminating application of chemicals as means to improve crop growth, development and yields for several years has become problematic to agricultural sustainability because of the adverse effects these chemicals have on the produce, consumers and beneficial microbes in the ecosystem. Therefore, for agricultural productivity to be sustained there are needs for better and suitable preferences which would be friendly to the ecosystem. The use of microbial metabolites has become an attractive and more feasible preference because they are versatile, degradable and ecofriendly, unlike chemicals. In order to achieve this aim, it is then imperative to explore microbes that are very close to the root of a plant, especially where they are more concentrated and have efficient activities called the rhizosphere. Extensive varieties of bacteria, archaea, fungi and other microbes are found inhabiting the rhizosphere with various interactions with the plant host. Therefore, this review explores various beneficial microbes such as bacteria, fungi and archaea and their roles in the environment in terms of acquisition of nutrients for plants for the purposes of plant growth and health. It also discusses the effect of root exudate on the rhizosphere microbiome and compares the three domains at molecular levels.

Cymbopogon citratus is an aromatic plant of Gramineae family well-known as lemon grass. Cymbopogon is derived from Greek word “kymbe – pogon” which means boat-beard. The lemon-like scent could be ascribed to the existence of a cyclic monoterpene (citral). The herb is a perennial grass, native and distributed in Asia, Africa, South and North America. It contains considerable group of flavonoids, essential oils, phenolic compounds and other phytochemical constituents which possesses pharmacological activities such as anti-obesity, anti-bacterial, anti-fungal, anti-nociceptive, anti-oxidants anti-diarrheal, and anti-inflammatory properties which could enhance health. Owing to its volatility and lemon-like aroma, citronella oil is used as deodorants in cosmetics, toiletries, insecticides (bio-pesticide) and spent grass in agriculture, in pharmaceutical and chemical industries it is incorporated in the manufacture of perfumes, fragrances, soaps, detergents, aftershaves, cosmetics and as culinary flavor in food industries. This literature review was tailored to widely investigate the ethnobiological, phytochemical compounds and pharmacological assays in attempt to divulge other plausible therapeutic activities. Keywords: Phytochemical constituents, Citral, Essential oil, Pharmacological activities, Lemon grass

Soil is comprised of minerals, soil organic matter, water and air. The composition and proportion of these components greatly influence soil physical properties like structure and porosity. Soil bacteria and fungi play pivotal roles in various biogeochemical cycles and are responsible for the cycling of organic compounds. The view on the microbiological safety of drinking water is changing. The demand for the total absence of any pathogenic organism is no longer significant in light of the new pathogens, some of which are capable of growing in drinking water systems. This is mainly due to many pollutants that are present at much higher concentrations in groundwater than they are in most contaminated surface supplies. In order to determine the microbes, soil and water samples were collected from petrochemical industry, Eleme, Port-Harcourt, Rivers State, Nigeria, for microbiological analysis. This was carried out by the isolation, assessment and characterization of the isolated organisms. The highest bacterial counts was determined in soil sample 1 (SS1) and water sample 4 (WS4) with microbial loads of 1.48 x 10^6 cfu/mL and 9.40 x 10^5 cfu/mL and the lowest count was found in soil sample 2 (SS2) and water sample 2 (WS2) with microbial load 2.90 x 105 cfu/mL and 3.67 x 10^4 cfu/mL. The highest fungal counts was determined in soil sample 2 (SS2) and water sample1 (WS1) with microbial loads of 1.76 x 10^6 cfu/mL and 2.17 x 10^6 cfu/mL and the least colonies was in soil sample 1 (SS1) and water sample 2 (WS2) with microbial counts of 1.75 x 10^5 cfu/mL and 4.30 x 10^4 cfu/mL. The results present that the presence of these microbes can be linked to the prehistory of the effects or contamination of surface and underground water in this region and could leads to water-borne diseases.

Senna alata (L.) Roxb. (Fabales: Fabaceae) is a medicinal plant basically used as antifungal and sometimes as antibacterial. Local people believe it is the amount of the plant consumed that constitutes to its potency, other believe it is the incantation thereby disregarding the bioactive components present in the leaf of S. alata. Therefore, there is a need to examine this claim by examining the bioactive components that are present in the plant. The methanolic and ethanolic extracts were obtained using soxhlet apparatus and the concentrated extracts were purified using column chromatography; the fractions were eluted and screened for their phytochemical and the mass spectroscopic analysis was performed using a mass spectrophotometer. The antimicrobial activity was carried out using agar disc diffusion method. The phytochemical analysis revealed the presence of important secondary metabolites such as anthraquinone, flavonoid and saponins while steroids was absent in the leaf extracts. The molecular ions of 250, 250, and 222 were obtained from the mass spectra. This showed the presence of methaqualone, cinnamic acid and isoquinoline. Ethanolic extracts showed a higher antimicrobial activity when compared with the methanolic extracts but less activity when compared with the standard used (amoxicillin). It could be concluded that the presence of these phytochemicals could be responsible for the observed antifungal and antibacterial activities on the susceptible organisms studied of the plant and also can be a natural source of antimicrobial substances of high importance.