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.

Mycorrhizae are symbiotic associations between fungi and host plants, which confer several advantages, including good mineral nutrition. Arbuscular mycorrhizal fungi (AMF) then present an effective alternative in order to develop a sustainable agriculture that is less dependent on mineral fertilizers. The objective of this study was to assess the impact of organic fertilizers based on native arbuscular mycorrhizal fungi on increasing maize productivity and improving soil health in North Benin. For this study, three mycorrhizal fungi strains (Glomeraceae sp., Acaulosporaceae sp. and Diversisporaceae sp.) were used with or without mineral fertilizers. The corn variety 2000 SYN EE-W was used. The experimental design is a randomized complete block of nine treatments with three replicates. After 65 days, the endomycorrhizal infection was evaluated. The results showed that mycorhizal fungi had a positive impact on the different plant growth parameters (height, leaf area, and yield). At the height level, Acaulospora + ½ dose of N 15 P 15 K 15 recommended + urea produced good results compared to the control, an increase of 24.9%. The same observations were made for leaf area and yield, an increase of 70.4 and 39.04%, respectively. However, the results show that the rate of endomycorrhizal infection is high with Diversisporaceae sp. + 50% of recommended N 15 P 15 K 15 + urea followed by Glomeraceae sp. + 50% of recommended N 15 P 15 K 15 + urea and Acaulosporeacea sp.+ 50% of recommended N 15 P 15 K 15 + urea. In terms of spore number, the treatment Glomeraceae sp. gave the best result.

Crabs play an important economic and bio-ecological role in most aquatic ecosystems and occupy an important place in the variety of trophic niches. Callinectes amnicola Rochebrune and Cardisoma armatum Herklots are two edible species widely exploited in Benin. The present work aims to i) evaluate the socioeconomic and cultural importance of those two crab species, ii) analyze the dynamics of the value chain, and iii) monitor the flow of their resources. Surveys were carried out during February 2018 to September 2019 among target groups in Ouémé, Atlantic and Littoral administrative Departments of Benin through structured and semi-structured interview methods as well as free interview. Results indicate that fishermen/catchers (12.76%), wholesalers/collectors (25.53%) and retailers (61.70%) are the actors involved in the crab value chain. Between 40 and 50% of fishery products are exported to markets in Togo and Ghana. Not all of the exoskeletons resulting from post-capture losses and those resulting from treatments for consumption, in particular C. amnicola (74.46%) and C. armatum (76.59%) are used, which poses an environmental management problem. The gains made in the sector vary from 8.000±2.828 Financial Community African Franc (FCAF) (C. amnicola) to 20.000±21.213 FCAF (C. armatum). The study found that crabs (C. armatum and C. amnicola) have remarkable socioeconomic importance in Southern Benin, Africa.