Bioremediation potential and lead removal capacity of heavy metal-tolerant yeasts isolated from Dayet Oum Ghellaz Lake water (northwest of Algeria).

Seven metal-resistant yeast strains were isolated and selected from Dayet Oum Ghellaz Lake water (northwest of Algeria) known as a highly polluted area by lead and cadmium. The yeast strains were screened on the basis of their resistance to seven heavy metals Hg, Cr, Cd, Pb, Cu, Zn, and Fe and characterized by molecular and phylogenetic analysis. The sequencing of the D1/D2 domain of the 26S rRNA genes revealed the affiliation of the seven yeast isolates to Rhodotorula mucilaginosa, Clavispora lusitaniae, and Wickerhamomyces anomalus species. All yeast strains were halotolerant as they were able to grow in 10-15% NaCl. The yeast isolates were highly resistant to the studied heavy metals and exhibited different tolerance according to the metal type. The highest minimum inhibitory concentrations (MIC) were observed in R. mucilaginosa RO7 and W. anomalus WO2 strains which were then selected for lead removal assays. The present study is the first to investigate the lead elimination by W. anomalus. The lead uptake was significantly affected by biomass concentration in a reverse relationship, with purification percentages estimated at 98.15 ± 0.9% and 97.046 ± 0.47% and removal efficiency of 12.68 ± 0.91 and 15.55 ± 0.72 mg/g for W. anomalus WO2 and R. mucilaginosa RO7, respectively. The investigated metal-tolerant yeast strains proved to be promising candidates for bioremediation processes of heavy metals. This work amends the metal-resistant yeast bank with new strains having interesting abilities to resist to relatively high concentrations of toxic heavy metals and which can be used in the near future as low-cost biosorbents.

Morphological characterization of mycorrhizae formed between three Terfezia species (desert truffles) and several Cistaceae and Aleppo pine.

Six Cistaceae species, Helianthemum ledifolium, Helianthemum lippii, Fumana procumbens, Cistus albidus, Cistus incanus, Cistus salvifolius, and Pinus halepensis (Aleppo pine) were inoculated with three mycorrhizal desert truffles, Terfezia leptoderma, Terfezia boudieri, and Terfezia claveryi under greenhouse conditions, on soil originating from desert truffle natural habitat in Algeria. The syntheses have led to the formation of typical endomycorrhizae in annual Cistaceae (H. ledifolium) and perennial ones (H. lippii and F. procumbens) and an ectomycorrhiza with a less developed sheath in Cistus species and Aleppo pine. These results demonstrate the plasticity of Terfezia species to form different mycorrhizal types. The formation of an endomycorrhiza with H. ledifolium and F. procumbens and a sheathing ectomycorrhiza with P. halepensis inoculated by T. leptoderma in in vivo culture conditions was obtained for the first time.

Bioclimatic Origin Shapes Phylogenetic Structure of Tirmania (Pezizaceae): New Species and New Record from North Africa.

The phylogenetic relationships among Tirmania were investigated using the internal transcribed spacer (ITS) and large subunit (LSU) regions of the nuclear-encoded ribosomal DNA (rDNA) and compared with morphological and bioclimatic data. The combined analyses of forty-one Tirmania samples from Algeria and Spain supported four lineages corresponding to four morphological species. Besides the two previously described taxa, Tirmania pinoyi and Tirmania nivea, here we describe and illustrate a new species, Tirmania sahariensis sp. nov., which differs from all other Tirmania by its distinct phylogenetic position and its specific combination of morphological features. We also present a first record of Tirmania honrubiae from North Africa (Algeria). Our findings suggest that restrictions imposed by the bioclimatic niche have played a key role in driving the speciation process of Tirmania along the Mediterranean and Middle East.

Growth promotion and mycorrhizal colonization of Argan (Argania spinosa (L.) Skeels) inoculated with the edible desert truffle Tirmania nivea (Desf.) Trappe.

This study presents the first evidence of the mycorrhizal compatibility between the edible desert truffle Tirmania nivea and the valuable fruit tree Argania spinosa. Seed germination trials demonstrated that soaking pre-treatment of argan seeds in hydrogen peroxide (9%) for five days combined with the application of a fungicide treatment on an inert sowing material maximized the seed germination of this tree species. The mycorrhizal synthesis was conducted under greenhouse conditions by inoculating, in vivo, the host plant seedlings with spores of T. nivea. The growth and mycorrhizal status of A. spinosa was assessed 15.5 months after inoculation. The desert truffle mycorrhization significantly promoted all the investigated morphological parameters of growth and improved the physiological performances of the host plant through enhancing plant water status and chlorophyll concentration. The mycorrhizal symbiosis led to the formation of typical desert truffle endomycorrhizae with intracellular coils. The resistance of A. spinosa to the harsh environmental conditions of desert habitats makes it a potential candidate for cultivation of desert truffles.

Mycochemical composition and insecticidal bioactivity of Algerian desert truffles extract against two stored-product insects: Sitophilus oryzae (L.) (Coleoptera: Curculionidae) and Rhyzopertha dominica (F.) (Coleoptera: Bostrychidae).

The present study aimed to highlight the insecticidal activity of the Algerian desert truffle Terfezia claveryi Chatin against two post-harvest pests of rice and other cereal products, the rice weevil Sitophilus oryzae (L.), and the lesser grain borer Rhyzopertha dominica (F.), using direct contact application method with the filter paper impregnation technique. Soxhlet apparatus was used for extraction with chloroform as solvent. The major compounds in chloroform extract of T. claveryi were identified using gas chromatography-mass spectrometry (GC-MS). The two-way ANOVA was used for statistical analysis to determine the exposure time and doses with the greatest insecticidal activity. Findings of this study revealed that the major compounds were fatty acids: linoleic acid, methyl ester (14.84%), 11,14-eicosadienoic acid, methyl ester (11.55%), oleic acid, methyl ester (7.1%), and palmitic acid (6.96%). However, chamazulene (0.88%) was found to be minor compound. Our results describe for the first time the presence of chamazulene in desert truffle. The result showed also that the most potent insecticidal activity of chloroform extract of T. claveryi was found towards S. oryzea with LD50 value of 162.11 µg/mL. For concentrations of 250 and 300 µg/mL, this extract was able to eradicate 96.65 ± 1.15% and 100.0 ± 0.0% of S. oryzea after 24 h of exposure. However, it caused only 47.24 ± 1.15% and 50.66 ± 1.15% of mortality of R. dominica, respectively, after 6 days. This work offers promising prospects for the use of desert truffles extracts as a potential insecticidal agent for improving quality and safety of stored foods against damage caused by stored-product pests.

Contrasted Genetic Diversity, Relevance of Climate and Host Plants, and Comments on the Taxonomic Problems of the Genus Picoa (Pyronemataceae, Pezizales).

The species concept within the genus Picoa Vittad. is here revisited in light of new molecular and ecological data obtained from samples collected throughout the Mediterranean basin. Two highly diverse widespread clades and four additional minor lineages were significantly supported by three genes dataset (ITS, 28s LSU and RPB2) inferences for 70 specimens. The two widespread clades occur in very different geographical and ecological areas associated with exclusive host plants in the genus Helianthemum. SEM study of spore surface morphology in these lineages revealed the existence of smooth ascospores in the majority of these clades. However the most frequent lineage in Europe and coastal North Africa displayed either smooth or verrucose spores. Hence this morphological criterion cannot be reliably used to discriminate between the different clades. In addition, SEM observations made on ascospores from several original collections of P. juniperi and P. lefebvrei supported the hypothesis that ornamentation depends on the degree of maturity in some of these lineages. Geographical and ecological, rather than morphological data are here suggested as the most useful characters to separate the different lineages in Picoa. Further studies focusing on these features are needed before the names P. juniperi and P. lefebvrei can be unambiguously linked with the genetic lineages observed.