Unconventional Secretion of Nigerolysins A from Aspergillus Species

Author: mycolabadmin
2020-12-11
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Summary

This research investigated how certain fungi secrete defensive proteins that help protect them against predatory insects. The study focused on special proteins called nigerolysins in Aspergillus fungi, revealing they are released through an unusual secretion process and are found throughout the fungal cells. This knowledge helps us understand how fungi defend themselves in nature. Impacts on everyday life: • Helps develop better natural pesticides for crop protection • Improves our understanding of fungal defense mechanisms in nature • Could lead to new applications in biotechnology and protein production • Contributes to safer and more sustainable agricultural practices • Advances our knowledge of beneficial and harmful fungi that affect daily life

Background

Aegerolysins are small lipid-binding proteins particularly abundant in fungi. Previous research showed that aegerolysins from oyster mushrooms can interact with insect-specific membrane lipids and form pesticidal pore-forming complexes. Similar interaction was recently demonstrated for nigerolysin A2 from Aspergillus niger. In Aspergillus species, aegerolysins are frequently found as secreted proteins, suggesting a role in fungal defense.

Objective

To investigate the subcellular localization and secretion mechanisms of nigerolysins A in A. niger using immunocytochemistry and live-cell imaging, while examining their secretion through prediction tools and Western blotting. Additionally, to conduct detailed bioinformatics analysis of Aspergillus aegerolysins to understand their distribution and potential functions across species.

Results

The study confirmed that both nigerolysins A are leaderless proteins that reach the cell exterior through unconventional protein secretion. NigA proteins were found to be evenly distributed in the cytoplasm of fungal hyphae. Bioinformatics analysis revealed that similar function occurs only in a limited number of aegerolysins. The same or similar pesticidal protein functions were predicted in species of the subgenus Circumdati, section Nigri, series Nigri, and some other species with adjacent pairs of putative pesticidal proteins.

Conclusion

The research demonstrated that nigerolysins A are secreted through unconventional pathways and are distributed throughout fungal cytoplasm rather than just at hyphal tips. The study suggests these proteins may be released when cells are broken by predator feeding or through autolysis. The findings indicate that aegerolysin orthologues found in certain Aspergillus species likely serve similar pesticidal functions as those found in oyster mushrooms, particularly against invertebrate predators.

Published in:Microorganisms,
Study Type:Laboratory Research,
Source: 10.3390/microorganisms8121973