Plant growth promoting rhizobacteria: Beneficial effects for healthy and sustainable agriculture

It is unanimously admitted that the chemical fertilizers and pesticides used in modern agriculture create a real environmental and public health problems. One of the promising solutions to substitute these agrochemicals products is the use of bio-resources, including plant growth promoting rhizobacteria (PGPR). The PGPR focused more and more scientific attention in recent decades. These rhizospheric bacteria colonize actively the root system of plants and improve their growth and yield. The PGPR use different mechanisms of action to promote plant growth. These mechanisms were grouped into three clusters according to the PGPR effects on plant physiology. These groups are as follow: (i) biofertilization including biological fixation of atmospheric nitrogen, phosphate solubilization, siderophores production and exopolysaccharides production; (ii) phytostimulation including production of indole acetic acid, gibberellins, cytokinins and ethylene; and (ii) biocontrol including induction of systemic resistance, competition for iron, nutrient and space, production of antibiotics, lytic enzymes, hydrogen cyanide and volatile compounds. In view of the latest advances in PGPR biotechnology, this paper proposes to do the review on PGPR in rhizosphere and describes the different mechanisms used by PGPR to promote the plants growth and health. In prospect to a healthy and sustainable agriculture, respectful of environment, the PGPR approach revealed as one of the best alternatives.Keywords: Rhizosphere, plant growth promoting rhizobacteria (PGPR), root colonization, biofertilization, biocontrol, biostimulation, interaction plant-microorganisms, sustainable agricultur

PHYTOCHEMISTRY AND BIOLOGICAL ACTIVITIES OF CRATEVA ADANSONII EXTRACTS

Objective: This study aims to search the secondary metabolites of Crateva adansonii (leaves and bark) and evaluate some biological activities (antimicrobial, antioxidant and cytotoxicity's property) of these extracts.Methods: The phytochemical screening was made with standard method. Agar diffusion method was used for antibacterial activity coupled with Minimum Inhibitory Concentration (MIC) and Bactericidal (MBC) determination. The antifungal test was performed by the mycelial development reduction method. DPPH method was used to evaluate the extracts antioxidant activity. Artemia salina larvae were use as support to evaluate the toxicity of the extracts.Results: The results of the phytochemical screening reveal the presence of polyphenols, triterpenoids, and glycosides in the both organs (leaves and bark) of C. adansonii. All the extracts have low activity on the reference strains with a larger diameter of 17±00 mm (S. oralis). Only the ethanolic and hydroethanolic leaf's extracts inhibited respectively 20% and 10%, of the clinical strain S. aureus. The ethyl acetate leaf's extract shows the best antifungal activity (89,19%) with A. clavatus. All extracts present dose-dependent antiradical properties and are non-toxic for the cells of Artemia salina. C. adansonii bark extracts had the best reducing power (23,80±0, 137 mmol/g EqAA EAA) of the DPPH radical.Conclusion: C. adansonii is therefore an active principle source for the development of drugs to antimicrobial and antioxidant activitie

Phytochemical Screening and Biological Activities of Combretum adenogonium Leaves Extracts

Combretum adenogonium is beniniens pharmacopoeia medicinal plant used for the treatment of various diseases. This work aims to study the phytochemical and assess some biological activities of C. adenogonium leaves extracts. The phytochemical analysis (qualitative et quantitative) was conducted by standard analytical chemistry method. Antioxydant activity was evaluated by the DPPH method. Antibacterial activity was evaluated in vitro with 10 references strains , 10 Staphylococcus strains isolated from European Scientific Journal October 2017 edition Vol.13, No.30 ISSN: 1857 – 7881 (Print) e - ISSN 1857- 7431 359 meat products and 10 clinical Staphylococcus aureus strains isolated from Buruli ulcer lesions and pus. The Minimum Inhibitory Concentration (MIC) and Bactericidal (CMB) were determined by macrodilution method. The extracts cytotoxic effect was evaluated with Artemia salina larvae. The phytochemical screening revealed the presence of flavonoids, tannins, anthocyanins, saponin and triterpenoids. The methanolique extract present the higest content (450.66 ± 0.004 µg EAG/mg) of total polyphenolic compound. The results showed the good antioxidant activity. The inhibitory diameter zone vary (p < 0.001) according to the strains. The largest medium inhibitory diameter (21.85 ± 0.17 mm) was obtained with the ethanolic extract, while the lowest (6.00 ±0.00 mm) were recorded with water-ethanol extract. The variation between CMI and CMB is not significant (p > 0.05). The higher LD50 (27.66 mg/ml) was recorded with methanol extract. The results of this study confirm some use of C. Adenogonium extracts. But; these extracts must be use with moderatio

State of the Art and Contribution to the Documentation on Fishing, Aquaculture and on the Microbiological Profile of Clarias gariepinus and Oreochromis niloticus Two Species of Fish Reared in the Whedos of the Upper Ouémé Delta in the Republic of Benin

Fish is an important source of animal protein in Africa and is used in the composition of several national dishes. This literature review examines fishing, aquaculture and fish reared in the whèdos of the upper Ouémé delta in Benin. It addresses socio-economic aspects, nutritional importance and traditional fish preservation technology. The sources of information used are publications, books, reports of dissertations and theses and technical notes. It was found that Clarias gariepinus and Oreochromis niloticus, among others, are two species of fish most often raised in the whèdos of the Ouémé River in Benin.  These fish adapt to large variations of ecological factors of the aquatic environment found everywhere in Africa and reproduce easily in captivity, which favors their breeding in ponds. These species present multiple fish farming qualities: resistance to high densities, resistance to diseases and low oxygen levels, easy adaptation to artificial feeding and high growth. Microbiological contamination of fish flesh occurs only after capture and can be endogenous or exogenous contamination. Generally, several processes are used to overcome this problem of contamination of fish. Hot smoking and drying are very often used. The lack of hygiene in the traditional technology of smoking fish sometimes favor a considerable microbial contamination of the obtained products. Thus, contaminated fish can be the cause of foodborne diseases such as food poisoning. Most of the pathogenic strains responsible for these diseases are resistant to certain antibiotics

State of the Art and Contribution to the Documentation on Fishing, Aquaculture and on the Microbiological Profile of Clarias Gariepinus and Oreochromis Niloticus Two Species of Fish Reared in the Whedos of the Upper Ouémé Delta in the Republic of Benin

Fish is an important source of animal protein in Africa and is used in the composition of several national dishes. This literature review examines fishing, aquaculture and fish reared in the whèdos of the upper Ouémé delta in Benin. It addresses socio-economic aspects, nutritional importance and traditional fish preservation technology. The sources of information used are publications, books, reports of dissertations and theses and technical notes. It was found that Clarias gariepinus and Oreochromis niloticus, among others, are two species of fish most often raised in the whèdos of the Ouémé River in Benin. These fish adapt to large variations of ecological factors of the aquatic environment found everywhere in Africa and reproduce easily in captivity, which favors their breeding in ponds. These species present multiple fish farming qualities: resistance to high densities, resistance to diseases and low oxygen levels, easy adaptation to artificial feeding and high growth. Microbiological contamination of fish flesh occurs only after capture and can be endogenous or exogenous contamination. Generally, several processes are used to overcome this problem of contamination of fish. Hot smoking and drying are very often used. The lack of hygiene in the traditional technology of smoking fish sometimes favor a considerable microbial contamination of the obtained products. Thus, contaminated fish can be the cause of foodborne diseases such as food poisoning. Most of the pathogenic strains responsible for these diseases are resistant to certain antibiotics

State of the Art and Contribution to the Documentation on Fishing, Aquaculture and on the Microbiological Profile of Clarias gariepinus and Oreochromis niloticus Two Species of Fish Reared in the Whedos of the Upper Ouémé Delta in the Republic of Benin

Fish is an important source of animal protein in Africa and is used in the composition of several national dishes. This literature review examines fishing, aquaculture and fish reared in the whèdos of the upper Ouémé delta in Benin. It addresses socio-economic aspects, nutritional importance and traditional fish preservation technology. The sources of information used are publications, books, reports of dissertations and theses and technical notes. It was found that Clarias gariepinus and Oreochromis niloticus, among others, are two species of fish most often raised in the whèdos of the Ouémé River in Benin.  These fish adapt to large variations of ecological factors of the aquatic environment found everywhere in Africa and reproduce easily in captivity, which favors their breeding in ponds. These species present multiple fish farming qualities: resistance to high densities, resistance to diseases and low oxygen levels, easy adaptation to artificial feeding and high growth. Microbiological contamination of fish flesh occurs only after capture and can be endogenous or exogenous contamination. Generally, several processes are used to overcome this problem of contamination of fish. Hot smoking and drying are very often used. The lack of hygiene in the traditional technology of smoking fish sometimes favor a considerable microbial contamination of the obtained products. Thus, contaminated fish can be the cause of foodborne diseases such as food poisoning. Most of the pathogenic strains responsible for these diseases are resistant to certain antibiotics

ANTIMICROBIAL, ANTIOXIDANT, CYTOTOXIC ACTIVITIES AND PHYTOCHEMICAL ASSESSMENT OF COLA ACUMINATA USED IN BENIN

Objective: The aim of this study was to make a phytochemical screening and measure some biological activities of Cola acuminata's seeds and leaves extracts.Methods: The secondary metabolite was detected by the method based on coloring and precipitation differential reactions. The antibacterial and antifungal activities were assessed in vitro by the macrodillution and solid medium agar diffusion method. 2,2-diphényl-1-picrylhydrazyl (DPPH) and 2,2'-azinobis-(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) methods were used to evaluate the antioxidant activity of the tested extracts of which larval cytotoxicity was studied.Results: Our data revealed that the seeds contain more polyphenols than the leaves. The seeds extracts displayed a good antibacterial activity against both reference strains and food Staphylococcus strains. The inhibition diameters varied from 7±2.82 to 21.5±4.94 mm. The smallest Minimum Inhibitory Concentrations (MIC) on the food strains (0.08 mg/ml) is twice less than the reference strains one (0.15 mg/ml), this observation is contrary to the Minimum Bactericidal concentrations (MBC). Susceptibility of fungal strains varies according to the extracts (p = 0.0016). The seeds ethyl acetate extracts had the best antioxidant activity with DPPH and ABTS methods. The Lethal Doses (LD50) showed that no extract was toxic.Conclusion: Cola acuminata seeds are richer than the leaves in compounds with biological activities. These two organs have interesting antimicrobial, antifungal and antioxidant activity variables depending to the extracts. The seeds have better biological activity than the leaves.Â

Mold Occurrence in Fresh Chilli Pepper (Capsicum spp.) Harvested Directly in the Field in Benin Republic

Introduction: The chilli pepper (Capsicum spp.), ranked among the world's leading spices or food additives, is now Benin'ssecond most-important vegetable crop after tomatoes. Unfortunately, chilli peppers are likely to be contaminated with mold which produces dangerous mycotoxins due to cultural practices, transport, and post-harvest storage. Objective: The purpose of this study is to isolate and identify the molds that contaminate chilli pepper varieties in open fields according to the cultivation methods used in the Republic of Benin. Materials and Methods: A total of 240 samples of three varieties of chilli peppers were taken directly from six districts of Benin. The molds were isolated and purified on a PDA (Potato Dextrose Agar) medium for identification. The identification focused on the morphological and cultural characteristics of isolated strains. Results: Nine (9) fungal genera from different taxonomic groups were detected. The genera that have been represented are Aspergillus (34%), Fusarium (21%), Penicillium (16%), Alternaria (7%), Cladosporium (7%), Mucor (7%), Scytalidium (4%), Trichophyton (3%), and Rhizopus(1%). Conclusion: The present study shows that chilli pepper is being contaminated in Benin. The genera Aspergillus, Fusarium, Penicillium, and Alternaria are respectively the main toxinogenic molds that contaminate peppers in the field. The mold control in chilli pepper against pathogenic agents became urgently required to reduce a consumer disease caused by chilli pepper in Benin

Identification of Extended-Spectrum -Lactamases Escherichia coli Strains Isolated from Market Garden Products and Irrigation Water in Benin

The present study aimed at biochemical and molecular characterization of Escherichia coli strains isolated from horticultural products and irrigation water of Cotonou. The samples were collected from 12 market gardeners of 4 different sites. Rapid' E. coli medium was used for identification of E. coli strains and the antimicrobial susceptibility was performed by the agar disk diffusion method. The -lactamases production was sought by the liquid acidimetric method. The genes coding for -lactamases and toxins were identified by PCR method. The results revealed that about 34.95% of the analyzed samples were contaminated by E. coli. Cabbages were the most contaminated by E. coli (28.26%) in dry season. All isolated strains were resistant to amoxicillin. The penicillinase producing E. coli carried bla TEM (67.50%), bla SHV (10%), and bla CTX-M (22.50%) genes. The study revealed that the resistance genes such as SLTI (35.71%), SLTII (35.71%), ETEC (7.15%), and VTEC (21.43%) were carried. Openly to the found results and considering the importance of horticultural products in Beninese food habits, it is important to put several strategies aiming at a sanitary security by surveillance and sensitization of all the actors on the risks of some practices

Contamination of Cereals (Sorghum Bicolor L. Moench and Pennisetum Glaucum (L.) R. Br.) During Storage: Farmer’s Perception and Management of Mold’ Contamination Risks

This study aimed to report the traditional technics used in Benin to store sorghum and millet grains and assess the knowledge level of the farmers and sellers on the problematic of mold contamination during the grain storage. Entire sorghum and millet production areas were carried out. Face-to-face interview of 1,040 farmers and sellers of both cereals were conducted. The data were collected according to an adapted set of questions based on direct observation, group discussions, individual interviews and garret visits containing sorghum and millet. The results were analyzed using SAS software. The survey results provided by this approach showed that 93.24% of farmers were men and 100 % of sellers were women. 68.92% of farmers had over 50 years old while 64.29% of sellers had less than 35 years. Their education level was relatively low and marked by 70% of unlettered. Several storage technics are used. The most widely used is solar drying, but it has the lowest shelf life compared to the second widely used to apply the chemical pesticides to cereals product. According to them, this technic allows a long shelf life for the cereals. The most of interviewed farmers and sellers (69%) use moldy grains in animal feed while 11% used it in human consumption. 13 % of both cereals were destroyed and 7 % of them ignore that mold can have caused the sanitary risks. In view of the socio-economic importance of the cereals and their role in the nutritional needs of people it become necessary to trained the farmer and sellers in other drying and storage technics in order to prevent food-borne diseases