Highly stable amyloid protein aggregates may help plant seeds last longer

July 23, 2020

Highly stable polymeric "amyloid" proteins, best known for their role in Alzheimer's disease, have been mostly studied in animals. But a new study on the garden pea publishing July 23, 2020 in the open-access journal PLOS Biology, by Anton Nizhnikov of All-Russia Research Institute for Agricultural Microbiology (ARRIAM) and colleagues, shows that they also occur in plants, and they may be an important adaptation for prolonging seed viability.

Amyloid is a type of protein conformation in which adjacent sheets of amino acids are bound together to form aggregates that are highly resistant to degradation. In animals, amyloids play roles in hormone storage and long-term memory formation, among other activities, but are best known from Alzheimer's disease, which is characterized by the formation of plaques of amyloid aggregates in the brain.

Direct evidence that plants form amyloids has been limited, but recent biochemical experiments have hinted at it, and a recent bioinformatic study led by Nizhnikov turned up a group of seed storage proteins with amino acid sequences that suggested they might be able to form amyloids.

In the new study, working in the garden pea, the researchers extracted the seed storage proteins, including one called vicilin, and analyzed both the full-length protein and two its domains called cupins that are rich in predicted amyloidogenic regions. When the genes were engineered into bacteria, all three proteins formed amyloid fibrils resistant to strong detergents; they also bound amyloid-specific dyes, and displayed unique spectral properties, all indicative of bona fide amyloid structure.

In vivo, in the pea seed, the authors used an amyloid-specific dye and an antibody to vicilin to show that the two co-localized--where there was vicilin, there was amyloid-specific dye. Vicilin amyloid aggregates built up in the storage vacuoles during seed maturation, and then rapidly disassembled during germination, suggesting their role is as a nutrient reservoir. They also found that vicilin amyloids survived intact in canned peas, resisted treatment with protein-digesting gastrointestinal enzymes, and were toxic to yeast and mammalian cells.

"Amyloids are highly stable protein structures that resist different treatments and can, in several cases, persist in the external environment for decades," Nizhnikov said. "Amyloid formation seems to be reasonable as evolutionary adaptation to provide for the long-term survival of plant seeds."
-end-
Peer reviewed; Experimental study; Plants

In your coverage please use this URL to provide access to the freely available article in PLOS Biology: https://journals.plos.org/plosbiology/article?id=10.1371/journal.pbio.3000564

Citation: Antonets KS, Belousov MV, Sulatskaya AI, Belousova ME, Kosolapova AO, Sulatsky MI, et al. (2020) Accumulation of storage proteins in plant seeds is mediated by amyloid formation. PLoS Biol 18(7): e3000564. https://doi.org/10.1371/journal.pbio.3000564

Funding: This work (study of amyloid formation by Vicilin and its domains in vivo and in vitro) was supported by the Russian Science Foundation, grant 17-16-01100. Part of this work performed by A.I. Sulatskaya (analysis of polymorphism of protein aggregates under various conditions) was awarded by RF President Fellowship SP-841.2018.4. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.

Competing Interests: The authors have declared that no competing interests exist.

PLOS

Related Science Articles from Brightsurf:

75 science societies urge the education department to base Title IX sexual harassment regulations on evidence and science
The American Educational Research Association (AERA) and the American Association for the Advancement of Science (AAAS) today led 75 scientific societies in submitting comments on the US Department of Education's proposed changes to Title IX regulations.

Science/Science Careers' survey ranks top biotech, biopharma, and pharma employers
The Science and Science Careers' 2018 annual Top Employers Survey polled employees in the biotechnology, biopharmaceutical, pharmaceutical, and related industries to determine the 20 best employers in these industries as well as their driving characteristics.

Science in the palm of your hand: How citizen science transforms passive learners
Citizen science projects can engage even children who previously were not interested in science.

Applied science may yield more translational research publications than basic science
While translational research can happen at any stage of the research process, a recent investigation of behavioral and social science research awards granted by the NIH between 2008 and 2014 revealed that applied science yielded a higher volume of translational research publications than basic science, according to a study published May 9, 2018 in the open-access journal PLOS ONE by Xueying Han from the Science and Technology Policy Institute, USA, and colleagues.

Prominent academics, including Salk's Thomas Albright, call for more science in forensic science
Six scientists who recently served on the National Commission on Forensic Science are calling on the scientific community at large to advocate for increased research and financial support of forensic science as well as the introduction of empirical testing requirements to ensure the validity of outcomes.

World Science Forum 2017 Jordan issues Science for Peace Declaration
On behalf of the coordinating organizations responsible for delivering the World Science Forum Jordan, the concluding Science for Peace Declaration issued at the Dead Sea represents a global call for action to science and society to build a future that promises greater equality, security and opportunity for all, and in which science plays an increasingly prominent role as an enabler of fair and sustainable development.

PETA science group promotes animal-free science at society of toxicology conference
The PETA International Science Consortium Ltd. is presenting two posters on animal-free methods for testing inhalation toxicity at the 56th annual Society of Toxicology (SOT) meeting March 12 to 16, 2017, in Baltimore, Maryland.

Citizen Science in the Digital Age: Rhetoric, Science and Public Engagement
James Wynn's timely investigation highlights scientific studies grounded in publicly gathered data and probes the rhetoric these studies employ.

Science/Science Careers' survey ranks top biotech, pharma, and biopharma employers
The Science and Science Careers' 2016 annual Top Employers Survey polled employees in the biotechnology, biopharmaceutical, pharmaceutical, and related industries to determine the 20 best employers in these industries as well as their driving characteristics.

Three natural science professors win TJ Park Science Fellowship
Professor Jung-Min Kee (Department of Chemistry, UNIST), Professor Kyudong Choi (Department of Mathematical Sciences, UNIST), and Professor Kwanpyo Kim (Department of Physics, UNIST) are the recipients of the Cheong-Am (TJ Park) Science Fellowship of the year 2016.

Read More: Science News and Science Current Events
Brightsurf.com is a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for sites to earn advertising fees by advertising and linking to Amazon.com.