The effects of herbicide application on two soil phosphate solubilizing bacteria: Pantoea agglomerans and Serratia rubidaea.

The application of synthetic pesticides is one of the fastest acting tools at farmers' disposal to prevent and mitigate the threats posed by plant pests in agriculture. However, the effects of these above-ground applications of pesticides are known to be detrimental to some belowground, non-target soil biota. At present, the effects many pesticides have on key functional microbial groups associated with phosphate (P) solubilization in the soil are still largely unknown. The purpose of this study was to compare the effects of two herbicides, glyphosate, and paraquat, on phosphate solubilizing bacteria (PSB) with and without pH adjustment (after herbicide addition) since pH is a major indicator of P solubilization. In our assay, two PSB strains (Pantoea agglomerans and Serratia rubidaea) were chosen to assess their ability to solubilize tricalcium phosphate (TCP) by using the vanadate-molybdate method (to measure the amount of P solubilized) in the presence of glyphosate (5.4 g/L and 10.8 g/L) or paraquat (2 g/L and 4 g/L) separately. To assess the effect of PSB treated by the herbicides, a growth experiment using PSB inoculated wheat seedlings was performed under greenhouse conditions (25 °C, light 16 h/8 h dark). After four weeks, wheat above-ground growth parameters were measured. Our results showed that even under recommended doses of glyphosate (5.4 g/L) and paraquat (2 g/L), a decrease in P solubilization activity was observed in P. agglomerans and S. rubidaea. Whilst paraquat affected TCP solubilization more than glyphosate with and without pH adjustment, there was a significant decrease (p < 0.05) in TCP solubilization, up to 39% and 93% in the presence of glyphosate and paraquat, respectively, for S. rubidaea, and up to 45% and 95% in the presence of glyphosate and paraquat, respectively, for P. agglomerans. The effect of the herbicides on the PSB had the same results as in the greenhouse test on wheat seedling growth, confirming that these herbicides have both above and belowground negative effects, despite being used at recommended doses.

Phosphate-Solubilizing Bacteria Isolated from Phosphate Solid Sludge and Their Ability to Solubilize Three Inorganic Phosphate Forms: Calcium, Iron, and Aluminum Phosphates.

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.

Chemical profile of Tetraclinis articulata (Vahl) Masters, and Juglans regia L. and Olea europaea L. var. Sylvestris used against oral diseases: in vitro analysis between polyphenolic content and aqueous extraction optimization.

OBJECTIVE: Optimization of aqueous extraction to extract the maximum amount of polyphenolic compounds that are used to treat oral disorders. METHODS: Using revelation tests for phytochemical screening, Folin-Ciocalteu reagent for total phenols, catechin standard for total flavonoids, acidified vanillin for total condensed tannins, and PCA analysis to detect different correlations between plants and between employed extractions. RESULTS: The highest (p < 0.0001); total flavonoides (195,80 ± 2,91 mg CE/g d.e) was obtained from decocted extract of Olea europaea L. subsp. europaea var. sylvestris, total phenolic (167,71 ± 12,52 mg GAE/g d.e) and total condensed tannins (250,44 ± 10,18 mg CE/g d.e) was obtained respectively from soxhlet extract and infused extract of Tetraclinis articulata L. whereas; The correlation analysis using Principal Component Analysis (PCA) was positive between infusion and decoction, between total flavonoids and total phenols which is not correlated with total condensed tannins. CONCLUSION: Juglans regia L. bark contain a higher level of polyphenolic constituents than leaves, Decoction extraction of Olea europaea L. var. sylvestris leaf recommended to increase the yield of polychenolic extracts, condensed tannins of Tetraclinis articulata L. are degradable in high temperature.

Oral disorders and ethnobotanical treatments: A field study in the central Middle Atlas (Morocco).

The present study was conducted in the Moroccan central Middle Atlas in order to inventory the plants used in the treatment of oral diseases, as well as to document possible risks of intoxication. Thus, 58 herbalists in the region were surveyed to gather ethnomedical information about the plants used in natural remedies preparation. The expression of the data obtained was achieved through the calculation of different quantitative indices, such as: use value (UV), family use value (FUV), relative frequency of citation (RFC), fidelity level (FL), informant consensus factor (ICF) and plant part value (PPV). 29 plants were inventoried, among which, Ruta montana L. has the highest use value (UV) and fidelity level (FL) for the treatment of gingivitis, respectively, 0.431 and 43.10. Marrubium vulgare L. has the highest citation frequency (RFC = 0.448). Whereas, Ammi visnaga (L.) Lam. had the highest value of the informant consensus factor (ICF = 0.846) as the most used species for the treatment of high number of oral pathologies and dental abscesses. Furthermore, the leaves generally prepared by decoction and administered by gargle constitute the most used part of the plant (PPV = 54.05). But, several plants recommended for the treatment of oral diseases are dangerous; in fact, Marrubium vulgare L., Atractylis gummifera L., Anacyclus pyrethrum L., Ruta montana L. and Peganum harmala L. were reported to be toxic by all the respondents. So, in spite of the virtues of medicinal plants, the toxic potential of some of them requires great vigilance in their therapeutic use.

Ruta chalepensis L. Essential Oil Has a Biological Potential for a Natural Fight against the Pest of Stored Foodstuffs: Tribolium castaneum Herbst.

Chemical pesticides used against insect pests of stored food have adverse effects on both health and the environment. So, the present study aims to evaluate the insect repulsive and insecticidal power of Ruta chalepensis L. essential oil (EO) from the region of Oulmes (Central plateau of Morocco); the ultimate objective is to develop a biological and ecological control strategy against pests. Thus, the EO obtained by hydrodistillation from the aerial parts of Ruta chalepensis L. was identified by GC-MS; its repellent and fumigant toxicity effects on adults of Tribolium castaneum Herbst were, respectively, investigated by the preferential area method on a filter paper and the inhalation test. The insecticide power was estimated by determining the percentage of mortality as a function of the duration of exposure and concentration of the EO. The essential oil obtained is characterized by the dominance of 2-undecanone (64.35%), piperonyl piperazine (11.9%), 2-decanaone (5.12%), 2-dodecanone (4.52%), decipidone (3.9%,) and 2-tridecanone (2.36%). This EO is endowed with a very repulsive power belonging to class V, which is strongly due to its majority compound 2-undecanone. The dose 0.038 µl/ml gave a repellent power of 100% after 15 min. The tests also revealed a considerable insecticidal effect, which reached 100% after 48 hours at a dose of 0.62 µl/ml. The calculation of the lethal dose causing 50% mortality (LD50) and the lethal times after which there is 50% mortality (LT50) allowed deducing that the insecticidal effect of Ruta chalepensis L. is time- and dose-dependent. Hence, the effectiveness of Ruta chalepensis L. EO attests that it can constitute a healthy alternative to fight against Tribolium castaneum Herbst.

The complete genome sequence of Ensifer meliloti strain CCMM B554 (FSM-MA), a highly effective nitrogen-fixing microsymbiont of Medicago truncatula Gaertn.

Strain CCMM B554, also known as FSM-MA, is a soil dwelling and nodule forming, nitrogen-fixing bacterium isolated from the nodules of the legume Medicago arborea L. in the Maamora Forest, Morocco. The strain forms effective nitrogen fixing nodules on species of the Medicago, Melilotus and Trigonella genera and is exceptional because it is a highly effective symbiotic partner of the two most widely used accessions, A17 and R108, of the model legume Medicago truncatula Gaertn. Based on 16S rRNA gene sequence, multilocus sequence and average nucleotide identity analyses, FSM-MA is identified as a new Ensifer meliloti strain. The genome is 6,70 Mbp and is comprised of the chromosome (3,64 Mbp) harboring 3574 predicted genes and two megaplasmids, pSymA (1,42 Mbp) and pSymB (1,64 Mbp) with respectively 1481 and 1595 predicted genes. The average GC content of the genome is 61.93%. The FSM-MA genome structure is highly similar and co-linear to other E. meliloti strains in the chromosome and the pSymB megaplasmid while, in contrast, it shows high variability in the pSymA plasmid. The large number of strain-specific sequences in pSymA as well as strain-specific genes on pSymB involved in the biosynthesis of the lipopolysaccharide and capsular polysaccharide surface polysaccharides may encode novel symbiotic functions explaining the high symbiotic performance of FSM-MA.

Specific Host-Responsive Associations Between Medicago truncatula Accessions and Sinorhizobium Strains.

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.

Thermophilic bacteria in Moroccan hot springs, salt marshes and desert soils.

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.

Thermophilic bacteria in Moroccan hot springs, salt marshes and desert soils

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.