For a long time, the people of Saudi Arabia have been using medicinal plants (MPs) as conventional medicine to heal diverse human and livestock diseases. The present work is the first study on ethnobotanical uses of 124 MPs species used by the local tribal communities of Jazan province in the Southwest of Saudi Arabia. Ethnobotanical data were collected by interviewing 174 local informants using semistructured interviews. Informants of different ages, from several settlements belonging to several tribal communities, were interviewed. It is worth noticing that the age of informants and their knowledge of MPs were positively correlated, whereas the educational level and MP knowledge of participants were negatively correlated. To find out if there was agreement in the use of certain plants in the treatment of given ailments, we used Informant Consensus Factor (ICF). To determine the most frequently used plant species for treating a particular ailment category by local people we used the fidelity level (FL%). The Relative Frequency of Citation (RFC) was used to indicate the local importance of a species and the relative importance (RI) level was used to check the therapeutic potentials of the cited plants. A total of 124 MPs belonging to 103 genera and 48 families were collected and identified. The majority of these plants were shrubs (45%), perennial herbs (21%), annual herbs (19%), or trees (18%). The Asteraceae (10.48%), Fabaceae (7.25%), and Apocynaceae (7.25%) families were the most represented. Leaves, fruits, and whole plant (24%, 18%, and 16%, respectively) were the most used plant parts in formulating traditional medicines.Ziziphus spina-christiandCalotropis procerawith the highest RI level (2.0) were found to have the highest range of therapeutic uses. They were followed byDatura stramonium(1.86),Withania somnifera,andAloe vera(1.81). The ICF ranged from 0.02 to 0.42 covering 12 disease categories with a prevalence of disease categories related to skin and hair problems (ICF=0.42) having 75 species cited, while 73 species were cited for gastrointestinal tract (GIT) disorders (ICF = 0.40).Senna alexandrina(67%),Tribulus terrestris(64%),Pulicaria undulata(60%),Leptadenia pyrotechnica(55%), andRumex nervosus(55%) had the highest FL which indicates their good healing potential against specific diseases. The high-FL species are the most promising candidate plants for in-depth pharmacological screening and merit further consideration. Accordingly, Jazan flora has good ethnobotanical potential. Unfortunately, many MP species are endangered by drought, overgrazing, and overexploitation. Some protection measures should be undertaken to prevent these species from becoming extinct. Natural reserves and wild nurseries are typical settings to retain medically important plants in their natural habitats, while botanic gardens and seed banks are important paradigms forex situconservation.

Nine isolates fromArgyrolobium uniflorum,Lotus creticus,Medicago sativa(Tunisia) andLotus arabicus(Senegal) were analysed by multilocus sequence analysis (MLSA) of five housekeeping genes (recA,atpD,glnA,gltAandthrC), the 16S rRNA gene and the nodulation genenodA. Analysis of the individual and concatenated gene sequences demonstrated that the nine new strains constituted three stable, well-supported (bootstrap and gene sequence similarity values) monophyletic clusters, A, B and C, all belonging to the branch of the genusEnsifer, regardless of the phylogenetic reconstruction method used (maximum likelihood, maximum-parsimony, neighbour-joining). The three groups were further characterized by API 100 auxanographic tests, host specificity andnodAgene sequence analysis. On the basis of these data, clusters A and C are suggested as representing two novel species within the genusEnsifer, for which the namesEnsifer numidicussp. nov. (type strain ORS 1407^T=LMG 24690^T=CIP 109850^T) andEnsifer garamanticussp. nov. (type strain ORS 1400^T=LMG 24692^T=CIP 109916^T) are proposed. The cluster B strains were assigned toEnsifer adhaerensgenomovar A.

Mycorrhizal symbioses are considered indicators of ecosystem biodiversity. However, their diversity and relevance in arid and semi-arid ecosystems are poorly understood. This study addressed this subject, the main objective being to evaluate arbuscular mycorrhizal fungi (AMF) diversity and heterogeneity in a semi-arid region. Samples of bulk and rhizosphere soil and fine roots ofMedicago truncatulawere collected at four different sites with the same aridity index (6.1), in Bou-Hedma National Park, Tunisia, a semi-arid ecosystem. AMF taxa were assessed by 454- pyrosequencing and identified by BLAST matching of operational taxonomic units (OTUs) against the MaarjAMdatabase, targeting AMF SSUrRNAgene diversity. Roots were the hotspots of AMF diversity (107 OTUs out of a total of 138). Of the 138 OTUs, 113 found correspondence in the MaarjAMdatabase, with 32 AMF virtual taxa (VTX),19 Site-exclusive (SE) and 13 common to at least two sites (Non-site exclusive, NSE); the remaining 25 OTUs grouped in 16 putative new AMF taxa (pNTX), each one consisting of OTUs sharing pairwise distances not higher than 3%. We found a high diversity and heterogeneity of AMF across the four sites, which showed, in a regression analysis, significant relation to six out of the eight environmental parameters evaluated: grazing activity and soil texture, electrical conductivity, organic matter, total phosphorus and total nitrogen. AMF colonization of plants also presented significant differences among the four sites, as well as spore density, microbial biomass and several enzymatic activities (dehydrogenase, β-glucosidase and phosphatase) evaluated in rhizosphere soils. The four sites clustered in two groups in a hierarchical clustering evaluation based on their AMF diversity (total numbers of OTU, VTX and pNTX) and the parameters referred above. The crucial role of abiotic factors, other than aridity index, on AMF community composition, was evidenced by the high heterogeneity found between AMF communities across sites under identical aridity conditions.