Project description:The conservation of the endangered Korean fir, Abies koreana, is of critical ecological importance. In our previous study, a yeast-like fungus identified as Aureobasidium pullulans AK10, was isolated and shown to enhance drought tolerance in A. koreana seedlings. In this study, the effectiveness of A. pullulans AK10 treatment in enhancing drought tolerance in A. koreana was confirmed. Furthermore, using transcriptome analysis, we compared A. koreana seedlings treated with A. pullulans AK10 to untreated controls under drought conditions to elucidate the molecular responses involved in increased drought tolerance.
Project description:Extracellular vesicles (EVs) are increasingly recognized as an important mechanism for cell-cell interactions. Their role in fungi is still poorly understood and they have been isolated from only a handful of species. Here, we isolated and characterized EVs from Aureobasidium pullulans, a biotechnologically important black yeast-like fungus that is increasingly used for biocontrol of phytopathogenic fungi and bacteria. After optimization of the isolation protocol, characterization of EVs from A. pullulans by transmission electron microscopy (TEM) revealed a typical cup-shaped morphology and different subpopulations of EVs. These results were confirmed by nanoparticle tracking analysis (NTA), which revealed that A. pullulans produced 6.1 × 10^8 nanoparticles per milliliter of culture medium. Proteomic analysis of EVs detected 642 proteins. A small fraction of them had signal peptides for secretion and transmembrane domains. Proteins characteristic of different synthesis pathways were found, suggesting that EVs are synthesized by multiple pathways in A. pullulans. Enrichment analysis using Gene Ontology showed that most of the proteins found in the EVs were associated with primary metabolism. When sequencing the small RNA fraction of A. pullulans EVs, we found two hypothetical novel mil-RNAs. Finally, we tested the biocontrol potential of EVs from A. pullulans. The EVs did not inhibit the germination of spores of three important phytopathogenic fungi – Botrytis cinerea, Colletotrichum acutatum, and Penicillium expansum. However, exposure of grown cultures of C. acutatum and P. expansum to A. pullulans EVs resulted in visible changes in morphology of colonies. These preliminary results suggest that EVs may be part of the antagonistic activity of A. pullulans, which is so far only partially understood. Thus, the first isolation and characterization of EVs from A. pullulans provides a starting point for further studies of EVs in the biotechnologically important traits of the biocontrol black fungus A. pullulans in particular and in the biological role of fungal EVs in general.
Project description:Aureobasidium pullulans is being studied with respect to its biotechnological applications in the degradation and modification of lignocellulose substrates or the production of the polysaccharide pullulan. In addition, the species is also used as a commercial plant protection agent against the bacterial pome fruit disease fireblight or against fungal postharvest diseases of fruits. The A. pullulans strain NBB 7.2.1 was originally isolated from a soil sample (from a Swiss orchard), but it was shown to be more competitive on apples than in soil (Gross et al., 2018). The antifungal activity of the isolate NBB 7.2.1 against fungal plant pathogens, and filamentous fungi in general, was assessed: Among 40 different yeasts, it belonged to the most strongly antifungal isolates (Hilber-Bodmer et al., 2017). The genome of A. pullulans NBB 7.2.1 was sequenced and de novo assembled by Agroscope using a combination of long reads from Pacific Biosciences Sequel technology and Illumina MiSeq short read data and subsequently annotated by JGI. The high quality genome sequence (comprising 12 chromosomes and one circular mitogenome) serves as the foundation for identifying the underlying molecular mechanisms that confer antifungal activity and to determine which factors may be targeted to improve the reliability and efficacy of A. pullulans as a plant protection agent in the field and under storage conditions.
This dataset contains raw reads for four replicates of three fungal culture supernatants
B1 Files: A_pul_F_ox: Interaction of A. pullulans and F. oxysporum in peptone buffer
B2 Files: Aureobasidium: Pure culture of A. pullulans in peptone buffer
B3 Files: Fusarium: Pure culture of F. oxysporum in peptone buffer