Jalal Soltani

Fungal Endophyte Diversity and Bioactivity in the Mediterranean Cypress Cupressus sempervirens

Fungal endophytes were isolated from the Mediterranean cypress Cupressus sempervirens. Eleven taxa of fungi, all within the Ascomycota, were identified based on PCR amplification and sequencing of the internal transcribed spacer sequences of nuclear ribosomal DNA (ITS rDNA) with taxonomic identity assigned using the NCBI nucleotide megablast search tool. The endophytic fungi included Alternaria multiformis, Didymella sp., Phoma sp., Phoma herbarum, Pyrenochaeta sp. (Dothideomycetes), Penicillium brevicompactum, Talaromyces sp. (Eurotiomycetes), Ascorhizoctonia sp. (Pezizomycetes), Thielavia microspora, and Thielavia spp. (Sordariomycetes). Considering the former findings in US, this indicates that similar ascomycetous classes of fungi, all from Pezizomycotina, associate with the healthy Cupressaceous trees in Iran. The recovered endophytes produced antifungal and antiproliferative metabolites which may contribute to the protection and survival of the host. We speculate that endophyte-infected C. sempervirens may benefit from their fungal associates by their influence on the ecology and biotic stress tolerance of the host plant. Moreover, a novel niche for the identified fungal species is being introduced.

Antiproliferative, Antifungal, and Antibacterial Activities of Endophytic Alternaria Species from Cupressaceae

Abstract Recent research has shown the bioprospecting of endophytic fungi from Cupressaceae. Here, we further uncover that the healthy cypress plants such as Cupressus arizonica, Cupressus sempervirens var. cereiformis, and Thuja orientalis host highly bioactive endophytic Alternaria fungal species. Indeed, endophytic Alternaria alternata, Alternaria pellucida, and Alternaria tangelonis were recovered from healthy Cupressaceous trees. Biodiversity and bioactivity of recovered endophytic Alternaria species were a matter of biogeography and host identity. We further extracted such Alternaria’s metabolites and highlighted their significant antiproliferative, growth inhibitory, and antibacterial activities against the model target fungus Pyricularia oryzae and the model pathogenic bacteria Bacillus sp., Erwinia amylovora, and Pseudomonas syringae. In vitro assays also indicated that endophytic Alternaria species significantly inhibited the growth of cypress fungal phytopathogens Diplodia seriata, Phaeobotryon cupressi, and Spencermartinsia viticola. In conclusion, since the recovered Alternaria species were originally reported as pathogenic and allergenic fungi, our findings suggest a possible ecological niche for them inside the foliar tissues of Cupressaceous trees. Moreover, in this study, the significant bioactivities of endophytic Alternaria species in association with Cupressaceae plant family are reported.

Bioactivity of endophytic Trichoderma fungal species from the plant family Cupressaceae

Trichoderma fungal species are universal soil residents that are also isolated from decaying wood, vegetables, infected mushroom and immunocompromised patients. Trichoderma species usually biosynthesize a plethora of secondary metabolites. In an attempt to explore endophytic fungi from healthy foliar tissues of the plant family Cuppressaceae, we explored Cupressus arizonica, C. sempervirens var. cereiformis, C. sempervirens var. fastigiata, C. sempervirens var. horizontalis, Juniperus excelsa, Juniperus sp. and Thuja orientalis plants and recovered several endophytic Trichoderma fungal strains from Trichoderma atroviride and Trichoderma koningii species. We found that the host plant species and biogeographical location of sampling affected the biodiversity and bioactivity of endophytic Trichoderma species. Furthermore, the bioactivity of Trichoderma isolates and the methanol extracts of their intra- and extra-cellular metabolites were assessed against a panel of pathogenic fungi and bacteria. Fungal growth inhibition, conidial cytotoxicity, minimum inhibitory concentration and minimum bactericidal concentration were evaluated and analyzed by statistical methods. Our data showed that both intra- and extracellular secondary metabolites from all endophytic isolates had significant cytotoxic and antifungal effects against the model target fungus Pyricularia oryzae and the cypress fungal phytopathogens Diplodia seriata, Phaeobotryon cupressi and Spencermartinsia viticola. Further research indicated their significant antimicrobial bioactivity against the model phytopathogenic bacteria Pseudomonas syringae, Erwinia amylovora and Bacillus sp., as well. Altogether, the above findings show for the first time the presence of T. atroviride and T. koningii as endophytic fungi in Cupressaceae plants and more importantly, the Trichoderma isolates demonstrate significant bioactivity that could be used in future for agrochemical/drug discovery and pathogen biocontrol.

Diverse and bioactive endophytic Aspergilli inhabit Cupressaceae plant family

Aspergilli are filamentous, cosmopolitan and ubiquitous fungi which have significant impact on human, animal and plant welfare worldwide. Due to their extraordinary metabolic diversity, Aspergillus species are used in biotechnology for the production of a vast array of biomolecules. However, little is known about Aspergillus species that are able to adapt an endophytic lifestyle in Cupressaceae plant family and are capable of producing cytotoxic, antifungal and antibacterial metabolites. In this work, we report a possible ecological niche for pathogenic fungi such as Aspergillus fumigatus and Aspergillus flavus. Indeed, our findings indicate that A. fumigatus, A. flavus, Aspergillus niger var. niger and A. niger var. awamori adapt an endophytic lifestyle inside the Cupressaceous plants including Cupressus arizonica, Cupressus sempervirens var. fastigiata, Cupressus semipervirens var. cereiformis, and Thuja orientalis. In addition, we found that extracts of endophytic Aspergilli showed significant growth inhibition and cytotoxicity against the model fungus Pyricularia oryzae and bacteria such as Bacillus sp., Erwinia amylovora and Pseudomonas syringae. These endophytic Aspergilli also showed in vitro antifungal effects on the cypress fungal phytopathogens including Diplodia seriata, Phaeobotryon cupressi and Spencermartinsia viticola. In conclusion, our findings clearly support the endophytic association of Aspergilli with Cupressaceae plants and their possible role in protection of host plants against biotic stresses. Observed bioactivities of such endophytic Aspergilli may represent a significant potential for bioindustry and biocontrol applications.

Sumac as a novel adjunctive treatment in hypertension: a randomized, double-blind, placebo-controlled clinical trial

Background: Sumac (Rhus coriaria L., Anacardiaceae) is a medicinal plant traditionally used for the treatment of cardiovascular disorders. This study was designed to evaluate the effects of Sumac fruits in hypertensive patients. Material and Methods: a randomized, double-blind, placebo-controlled clinical trial was conducted on 80 hypertensive patients who were receiving captopril (25 mg day−1). The patients were randomly divided into 2 groups: the first group received R. coriaria fruit capsules (500 mg twice a day) and captopril (25 mg once a day), and the second one received placebo capsules (500 mg starch twice a day) and captopril (25 mg once a day), for 8 weeks. Blood pressure (BP) and body weight index (BMI) in all patients were determined every week. Phytochemical analysis of R. coriaria fruits was performed by using HPLC-DAD/QTOF-MS for analysing its phenolic compounds. Results: data indicated that hypertension was decreased significantly in R. coriaria group compared to baseline and placebo groups after 8 weeks, but BMI did not demonstrate a marked change in comparison with baseline and placebo groups. Moreover, the most abundant phenolic compounds identified in R. coriaria fruits were luteolin, apigenin, and quercetin flavonoids. Discussion: this finding suggests that R. coriaria fruits could be used as an effective natural remedy for management of hypertension. Since flavonoids were the main chemical constituents of this plant, its antihypertensive activity could be attributed to such compounds.

Light, temperature, and aging dependent vegetative growth and sporulation of Colletotrichum gloeosporioides on different culture media

The fungal organism Colletotrichum gloeosporioides is the causative agent of anthracnose disease of Citrus fruits. It is recently introduced as a potential producer of anticancer metabolite paclitaxel. Here, we introduce the optimal conditions for growth and sporulation of C. gloeosporioides. We have considered four fungal culture media, that is potato dextrose agar (PDA), carnation leaf agar (CLA), potato carrot agar (PCA) and water agar (WA), based on which sporulation inducers like Watman or Fabriano filter papers could be added, and evaluated both for vegetative growth and sporulation. Three light regimens, i.e. continuous light, 16/8 hrs light/darkness, and continuous darkness were applied in combination with the culture media. All experiments were tracked on 7th, 15th, 21st, and 30th day after incubation. At 28°C, PDA and PCA culture media, under continuous light, provided the best condition for C. gloeosporioides maximal growth. Decreasing light periods decreased the fungal growth. Furthermore, fungal sporulation showed a high dependence on light, temperature and culture medium in use. Under 16/8 h light/darkness interval at the same temperature C. gloeosporioides sporulation was at its maximum on Fabriano paper placed on PDA medium. At a lower temperature, that is 22°C, C. gloeosporioides sporulation on the same culture media was highly defected. Furthermore, aging generally increased the fungal sporulation. Key words: Colletotrichum gloeosporioides, citrus, growth, conidiation, development.

Antibacterial Effects of Several Plant Extracts and Essential Oils on Xanthomonas arboricola pv. juglandis in vitro

Abstract Walnut bacterial blight, caused by Xanthomonas arboricola pv. juglandis, is the most destructive bacterial disease of the genus Juglans worldwide. X. a. pv. juglandis bacterium has shown resistance to copper bactericides. Here with the aim of exploring some sources of natural bactericides for biocontrol of this bacterium, antibacterial activities of essential oils and aqueous extracts from 24 higher medicinal plant species were investigated, in vitro, on X. a. pv. juglandis. In diffusion assays, the majority of tested plant extracts and essential oils showed antibacterial activities against this bacterium. Significant antibacterial activities were observed for aqueous extracts of Allium sativum, Daturea stramonium, Rosmarinus officinalis, Peganum harmala, Ricinus communis, and Mentha piperita. Essential oils of Ziziphora persicae, Mentha piperita, Mentha spicata, and Achillea vermiculatus showed the highest antibacterial effects on X. a. pv. juglandis.

Endophytism in Cupressoideae (Coniferae): A Model in Endophyte Biology and Biotechnology

Plants live in a close association with microorganisms in below ground soil and above ground air. Versatile endophytic communities of microorganisms often shape symbiotic relationships with host plants, enter the foliar and root tissues, and promote host’s health. Evidence suggests that Cupressoideae subfamily of Cupressaceae (Coniferae) harbors beneficial distinct fungal and bacterial endophytic communities. Besides, the fungal endophytic community in Cupressoideae harbors endohyphal bacteria which indirectly enhance the host plant’s health through interaction with their endophytic fungal hosts. Moreover, data from different experiments suggest that the endophytic communities of Cupressoideae could find applications in agroforestry for plant protection against biotic and abiotic stresses. The endophytic microorganisms isolated from the cupressaceous plants are also being regarded as a novel source of biomolecules with immediate significance in medicine and agroforestry. Thus, Cupressoideae, as an underexplored niche, exhibits great promises for endophyte biology and chemistry, as well as evolutionary studies, with potential uses in pharmaceutical, agricultural and biotechnological industries.