Biofertilizers are a key component of organic agriculture. Bacterial biofertilizers enhance plant growth through a variety of mechanisms, including soil compound mobilization and phosphate solubilizing bacteria (PSB), which convert insoluble phosphorus to plant-available forms. This specificity of PSB allows them to be used as biofertilizers in order to increase P availability, which is an immobile element in the soil. The objective of our study is to assess the capacity of PSB strains isolated from phosphate solid sludge to solubilize three forms of inorganic phosphates: tricalcium phosphate (Ca₃(PO₄)₂), aluminum phosphate (AlPO₄), and iron phosphate (FePO₄), in order to select efficient solubilization strains and use them as biofertilizers in any type of soil, either acidic or calcareous soil. Nine strains were selected and they were evaluated for their ability to dissolve phosphate in the National Botanical Research Institute’s Phosphate (NBRIP) medium with each form of phosphate (Ca₃(PO₄)₂, AlPO₄, and FePO₄) as the sole source of phosphorus. The phosphate solubilizing activity was assessed by the vanadate-molybdate method. All the strains tested showed significantly (p ≤ 0.05) the ability to solubilize the three different forms of phosphates, with a variation between strains, and all strains solubilized Ca₃(PO₄)₂ more than FePO₄ and AlPO₄.

The diversity of thermophilic bacteria was investigated in four hot springs, three salt marshes and 12 desert sites in Morocco. Two hundred and forty (240) thermophilic bacteria were recovered, identified and characterized. All isolates were Gram positive, rod-shaped, spore forming and halotolerant. Based on BOXA1R-PCR and 16S rRNA gene sequencing, the recovered isolates were dominated by the genus Bacillus (97.5%) represented by B. licheniformis (119), B. aerius (44), B. sonorensis (33), B. subtilis (subsp. spizizenii (2) and subsp. inaquosurum (6)), B. amyloliquefaciens (subsp. amyloliquefaciens (4) and subsp. plantarum (4)), B. tequilensis (3), B. pumilus (3) and Bacillus sp. (19). Only six isolates (2.5%) belonged to the genus Aeribacillus represented by A. pallidus (4) and Aeribacillus sp. (2). In this study, B. aerius and B. tequilensis are described for the first time as thermophilic bacteria. Moreover, 71.25%, 50.41% and 5.41% of total strains exhibited high amylolytic, proteolytic or cellulolytic activity respectively.

Legume plants interact with rhizobia to form nitrogen-fixing root nodules. Legume-rhizobium interactions are specific and only compatible rhizobia and plant species will lead to nodule formation. Even within compatible interactions, the genotype of both the plant and the bacterial symbiont will impact on the efficiency of nodule functioning and nitrogen-fixation activity. The model legume Medicago truncatula forms nodules with several species of the Sinorhizobium genus. However, the efficiency of these bacterial strains is highly variable. In this study, we compared the symbiotic efficiency of Sinorhizobium meliloti strains Sm1021, 102F34, and FSM-MA, and Sinorhizobium medicae strain WSM419 on the two widely used M. truncatula accessions A17 and R108. The efficiency of the interactions was determined by multiple parameters. We found a high effectiveness of the FSM-MA strain with both M. truncatula accessions. In contrast, specific highly efficient interactions were obtained for the A17-WSM419 and R108-102F34 combinations. Remarkably, the widely used Sm1021 strain performed weakly on both hosts. We showed that Sm1021 efficiently induced nodule organogenesis but cannot fully activate the differentiation of the symbiotic nodule cells, explaining its weaker performance. These results will be informative for the selection of appropriate rhizobium strains in functional studies on symbiosis using these M. truncatula accessions, particularly for research focusing on late stages of the nodulation process.

Le présent travail s’inscrit dans le cadre de la valorisation des ressources du Moyen Atlas central du Maroc en plantes médicinales et en savoir-faire traditionnel. Ainsi à l’aide de 280 fiches questionnaires, une enquête ethnobotanique a été menée pendant les mois de juin, juillet, août et septembre 2013 auprès des usagers ordinaires des plantes, dans les sept fractions tribales de la région d’Aguelmouss; 103 plantes furent inventoriées, réparties en 43 familles et 87 genres. L’analyse des résultats de l’enquête ethnobotanique montre que six familles sont à usage fréquent, avec une dominance des lamiacées. Quant aux espèces dominantes, il y a essentiellement Thymus willdenowii, Corrigiola telephiifolia, Caralluma europaea et Juniperus oxycedrus. Par ailleurs, La feuille est la partie la plus utilisée, la majorité des remèdes est préparée sous forme de décoction et les affections de l’appareil digestif figurent parmi les pathologies les plus traitées. The present study should be set in the framework of valorization of medical plants and traditional knowledge’s from central middle Atlas of Morocco. Using 280 survey forms, hethnobotanical study was conducted during the months of June, July, August and September 2013 on the therapeutic uses of spontaneous medical plants in the seven tribal fractions that compose Aguelmouss municipality; this phase revealed the occurrence of 103 medicinal species which are divided into 43 families and 87 genera. The analyses results showed that six families commonly used by the population with a clear dominance of Lamiaceae. Also, species with very high frequency of use are Thymus willdenowii, Corrigiola telephiifolia Caralluma europaea et Juniperus oxycedrus. Furthermore, leaves are the most used part and the majority of remedies are prepared as a decoction. In terms of the treated disease, disorders of the digestive system ranks first with a rate of 38.9%.

Summary: A pot experiment was conducted under glasshouse conditions to investigate the effect of inoculation with four arbuscular mycorrhizal (AM) fungi (Glomus clarum, G. etunicatum, G. manihotis, Gigaspora margarita), either individually or in a mixture, and withRhizobium leguminosarumbiovarphaseoli, on the growth, mineral nutrition, and contribution of biologically fixed N₂, to three nodulating bean (Phaseolus vulgaris) varieties (Carioca, Negro Argel and Rio Tibagi). The¹⁵N isotope dilution technique and three control crops (non‐nodulating bean,Panicum maximumand sorghum) were used to quantify the contribution of N₂fixation. There were significant differences between the capacity of the different AM fungi to infect and colonize the roots of the different bean varieties. Inoculation with AM fungi significantly increased production of dry matter by 8–23 % and the concentration of P in plants by 160–335%. A strongly positive correlation of % root colonization by AM fungi and plant P concentration and accumulation was observed which suggests that the observed inoculation responses were a result of improved P acquisition by the mycorrhizal roots. N derived from the atmosphere increased significantly with AM fungi inoculation, with Carioca showing the best response, followed by Negro Argel and Rio Tibagi, thereby showing the indirect and positive effect of AM fungi inoculation on the N₂‐fixing association betweenRhizobiumandPhaseolus vulgaris.

Phosphorus (P) is the most important macronutrient next to nitrogen for the growth and development of plants. But often unavailable for plants because of its high reactivity with many soil constituents. Thus, the use of phosphate solubilizing bacteria (PSBs) as biofertilizers seems to be an effective way to resolve the soluble phosphorus availability in soil. The present study was conducted to isolate and characterize rock PSB associated with the rhizosphere of wheat (Triticum aestivum L.) from fourteen different wheat-growing sites of Meknes region in Morocco. A total of one hundred ninety-eight (198) rock PSBs were isolated employing NBRIP medium amended with rock phosphate (RP), out of which five strains (A17, A81, B26, B106, and B107) were selected for their strong ability to dissolve RP and were tested in vitro for plant growth-promoting (PGP) traits including production of indole acetic acid (IAA), siderophores, hydrogen cyanide (HCN), and antifungal activity, as well as their response to the effect of extrinsic and intrinsic stress. The 16S rRNA gene sequencing and phylogenetic analysis identified these isolates belong to four genera, Pantoea, Pseudomonas, Serratia, and Enterobacter. The phosphate solubilization index (SI) of selected isolates ranged between 2.3 and 2.7, and the amount of solubilized phosphorus in the liquid medium varied from 59.1 to 90.2 µg mL⁻¹. HPLC analysis revealed that all the selected isolates produced multiple organic acids (oxalic, citric, gluconic succinic, and fumaric acids) from glucose under aerobic conditions. Except for the A81 strain, all selected isolates were able to produce IAA ranging between 2.9 and 21.2 µg mL⁻¹. The isolates A17, B26, and B107 showed the ability to produce siderophores ranging from 79.3 to 20.8% siderophore units. Only two strains (A17 and B26) were able to produce HCN. All selected isolates showed good resistance against different environmental stresses like 10–50 °C temperature, 0.5–2 g L⁻¹ salt concentration and 4.5–9 pH range, and against different antibiotics. The antagonistic effect showed that among the five selected strains, only two strains (B26 and A17) were able to suppress the growth of tested fungi. This study clearly indicates that our selected rock PSBs can be used as biofertilizers for grain crops after studying their interaction with the host crop and field evaluation.