Eliciting transcriptomic and antioxidant defensive responses against Rhizoctonia root rot of sorghum using the endophyte Aspergillus oryzae YRA3.

Environmental pollution due to the improper use of the chemical fungicides represents a vital ecological problem, which affects human and animal health, as well as the microbial biodiversity and abundance in the soil. In this study, an endophytic fungus Aspergillus oryzae YRA3, isolated from the wild plant Atractylis carduus (Forssk.) C.Chr, was tested for its biocontrol activity against Rhizoctonia root rot of sorghum. The antagonistic potential of A. oryzae YRA3 was tested against Rhizoctonia solani in vitro. A full inhibition in the growth of R. solani was recorded indicating a strong antagonistic potential for this endophyte. To investigate the chemical composition of its metabolites, GC/MS analysis was used and thirty-two compounds in its culture filtrate were identified. Among these metabolites, some compounds with an antifungal background were detected including palmitic acid, 2-heptanone, and 2,3-butanediol. To these antifungal metabolites the antagonistic activity of A. oryzae YRA3 can be attributed. In the greenhouse experiment, treating of the infected sorghum plants with A. oryzae YRA3 significantly reduced severity of the Rhizoctonia root rot by 73.4%. An upregulation of the defensive genes (JERF3), (POD) and (CHI II) was recorded in sorghum roots when were inoculated with A. oryzae YRA3. In addition, an increment in the activity of peroxidase and polyphenol oxidase, as well as the total phenolic content in the sorghum roots was also recorded. Furthermore, the results obtained from the greenhouse experiment revealed a growth-promoting effect for inoculating the sorghum plants with A. oryzae YRA3. It can be concluded that A. oryzae YRA3 can be a probable biological agent to control this disease in sorghum. However, its evaluation under field conditions is highly needed in the future studies.

Wood-decay fungi associated with decaying of coarse woody debris in Hail Region, North of Saudi Arabia.

The present study was conducted in order to describe the assemblage of wood decay fungi and mycomycetes associated with the Hail region in the North of Saudi Arabia by using incubation chambers. There was a collection of coarse woody debris from the study area, AL baithe, which was brought to the laboratory and placed inside a series of incubation chambers in which water was added. Over a period of several weeks, fruiting bodies appeared in these chambers which were morphologically analysed via AmScope stereomicroscope and molecular identification was carried out via ITS-1F and ITS-4R DNA sequencing methods. The obtained sequences after successful identification via BLAST analysis were submitted to the Genebank NCBI database. During the course of the study, a total of 20 species of different 14 families of wood-decay fungi were identified of which mycelium has been generated in incubation chambers. Among the identified wood-decay fungi, Phanerochaetaceae (03 species), Bionectriaceae (02 species), Hypocreaceae (02 species) and Chaetomiaceae (02 species) being the most frequent. Hence, the present study was the first one to report on the diversity of wood-decay fungi of Saudi Arabia and was successful in using incubation chambers to describe the specimens of wood-decay fungi associated with coarse wood debris.

Epigenetic Modifiers Affect the Bioactive Compounds Secreted by an Endophyte of the Tropical Plant Piper longum.

Seven endophytic fungi were isolated from the tropical medicinal plant Piper longum L. After preliminary screening, Phomopsis heveicola was selected for the epigenetic activation treatments. The antibacterial, antifungal, and antioxidant potentials of crude extracts obtained from the treatments (with and without epigenetic modifiers) were analyzed in vitro. The extracts inhibited growth of the human pathogens Pseudomonas aeruginosa, Shigella sonnei, Streptococcus pyogenes, and Salmonella typhi, as well as the phytopathogens Puccinia recondita, Rhizoctonia solani, Phytophthora infestans, and Botrytis cinerea. Furthermore, DPPH-scavenging activity was higher in valproic acid treated extracts. Volatile chemicals with known biological activities (measured with GC-MS/MS), were released in the valproic acid treatment. The antimicrobial potentials of the extracts were confirmed using MRM/MS analysis. The experiments revealed a new promising endophytic fungus, P. heveicola, to be utilized in biological plant protection and in biomedical applications.