Location: Food Quality LaboratoryTitle: Blistering1 modulates Penicillium expansum virulence via vesicle-mediated protein secretion
|PENG, HUI - Guangxi Normal University|
|PETER, KARI - Pennsylvania State University|
|LU, YINGJIAN - University Of Maryland|
Submitted to: Molecular and Cellular Proteomics
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 12/23/2019
Publication Date: 12/23/2019
Citation: Jurick II, W.M., Peng, H., Beard, H.S., Garrett, W.M., Macarisin, O., Peter, K., Gaskins, V.L., Yang, T., Lu, Y., Mowery, J.D., Bauchan, G.R., Cooper, B. 2019. Blistering1 modulates Penicillium expansum virulence via vesicle-mediated protein secretion. Molecular and Cellular Proteomics. https://doi.org/10.1074/mcp.RA119.001831.
Interpretive Summary: Penicillium expansum is a fungus that causes blue mold of stored apple and pear fruit. It also produces patulin, a toxin that reduces the quality and safety of processed apple foods and juices. In this study, we have identified a gene called Blistering1 that influences apple rot and patulin production. Specifically, we made a mutant in the Blistering1 gene and found that it has an impaired aggressiveness on apple fruit. It also produced 30 times less patulin toxin. Our results can be utilized by researchers to develop blue mold specific controls that will be beneficial to growers and processors of apple and pear fruit.
Technical Abstract: The blue mold fungus, Penicillium expansum, is a postharvest pathogen of apple that reduces fruit quality, produces harmful mycotoxins (patulin), and significantly contributes to food waste. To identify genes controlling fundamental mechanisms of P. expansum virulence, a random T-DNA insertional library was created from wild-type strain R19. A mutant was identified with reduced lesion development and a blistered hyphal phenotype, and the T-DNA was located within a single gene, reducing its RNA transcription in vitro and during apple infection. The gene, Blistering1, encodes a protein with a DnaJ domain, but otherwise has little resemblance to genes from fungi outside the Aspergillaceae. Because protein secretion is fundamental to this family of fungi that produces antibiotics, mycotoxins, and cheese, the secretion of proteins into liquid growth medium was monitored by mass spectrometry. The mutant failed to secrete specific enzymes needed to degrade plant cell wall carbohydrates and to catalyze the final three biosynthetic steps of patulin outside of the cell. Consequently, the sterilized culture broth had reduced capacity to degrade apple tissue, and it contained 30 times less patulin. Quantitative mass spectrometry of 3,282 mycelia proteins revealed that the mutant had altered cellular networks controlling protein processing in the endoplasmic reticulum, protein export, vesicle mediated transport, and endocytocis. The mutant also had decreased amounts of proteins controlling mRNA surveillance and RNA processing. Transmission electron microscopy of hyphal cross sections confirmed that the blistering1 defect led to the formation of abnormally enlarged endosomes or vacuoles. These data reveal that Blistering1 affects cell-wide aspects of internal and external protein processing involving vesicle-mediated transport in a family of fungi with medical, commercial, and agricultural importance.