How does ionizing radiation affect amyloidogenesis in plants?

Abstract

Purpose

Ionizing radiation is a harsh environmental factor that could induce plant senescence. We hypothesized that radiation-related senescence remodels proteome, particularly by triggering the accumulation of prion-like proteins in plant tissues. The object of this study, pea (Pisum sativum L.), is an agriculturally important legume. Research on the functional importance of amyloidogenic proteins was never performed on this species.

Materials and methods

Pea seeds were irradiated in the dose range 5–50 Gy of X-rays. Afterward, Fourier-transform infrared spectroscopy (FTIR) was used to investigate changes in the secondary structure of proteins in germinated 3-day-old seedlings. Specifically, we evaluated the ratio between the amide I and II peaks. Next, we performed protein staining with Congo red to compare the presence of amyloids in the samples. In parallel, we profiled the detergent-resistant proteome fraction by ultrahigh-performance liquid chromatography coupled with tandem mass spectrometry (UHPLC-MS). Differentially accumulated proteins were functionally analyzed in MapMan software, and the PLAAC tool was used to predict putative prion-like proteins.

Results

We showed a reduced germination rate but higher plant height and faster appearance of reproductive organs in the irradiated at dose of 50 Gy group compared with the control; furthermore, we demonstrated more β-sheets and amyloid aggregates in the roots of stressed plants. We detected 531 proteins in detergent-resistant fraction extracted from roots, and 45 were annotated as putative prion-like proteins. Notably, 29 proteins were significantly differentially abundant between the irradiated and the control groups. These proteins belong to several functional categories: amino acid metabolism, carbohydrate metabolism, cytoskeleton organization, regulatory processes, protein biosynthesis, and RNA processing. Thus, the discovery proteomics provided deep data on novel aspects of plant stress biology.

Conclusion

Our data hinted that protein accumulation stimulated seedlings’ growth as well as accelerated ontogenesis and, eventually, senescence, primarily through translation and RNA processing. The increased abundance of primary metabolism-related proteins indicates more intensive metabolic processes triggered in germinating pea seeds upon X-ray exposure. The functional role of detected putative amyloidogenic proteins should be validated in overexpression or knockout follow-up studies.

Graphical Abstract

Keywords:

• Abiotic stress
• prion-like proteins
• amyloid aggregates
• FTIR
• pisum sativum
• proteome

Disclosure statement

No potential conflict of interest was reported by the author(s).

Data availability statement

The mass spectrometry proteomics data were deposited to the ProteomeXchange Consortium via the PRIDE partner repository (Perez-Riverol et al. 2022) with dataset identifier PXD044798 and doi: 10.6019/PXD044798.

Additional information

Funding

This work was supported by the National Research Foundation of Ukraine grant number 2020.02/0316, the project of the EU NextGenerationEU through the Recovery and Resilience Plan for Slovakia 09I03-03-V01-00142, and the fellowship of the National Scholarship Program of the Slovak Republic 34147.

Notes on contributors

Maryna Kryvokhyzha

Kryvokhyzha Maryna is a postdoctoral researcher in Nitra, Slovakia. She is a plant molecular biologist interested in genetics, proteomics, and biotechnology. Specifically, Maryna contributed to understanding the impact of different modes of ionizing radiation exposure on gene expression and proteome.

Sergii Litvinov

Sergii Litvinov is a research associate in Kyiv, Ukraine. He is a plant and molecular biologist currently studying the effects of stress factors on the production of prion-like proteins in plants. His research is also related to radiation-induced genomic instability, DNA repair and transcriptional response to DNA damage.

Maksym Danchenko

Maksym Danchenko is a Principal Investigator in Nitra, Slovakia. Currently, he is focusing on sensitivity to chronic ionizing radiation of aquatic plants, leaf development in carnivorous plants, and unique germination of parasitic plants.

Lidiia Khudolieieva

Lidiia Khudolieieva is a Junior Scientist in Kyiv, Ukraine. She is a biotechnologist with scientific interests in plant tissue culture, fast-growing trees, and the influence of stress factors on plants, particularly exploring the phenomenon of accumulation of prion-like proteins.

Nataliia Kutsokon

Nataliia Kutsokon is a senior scientist in Kyiv, Ukraine. She is a plant biologist currently studying the effects of stress factors on the production of prion-like proteins in plants. Her research is also related to the biotechnology of fast-growing trees.

Peter Baráth

Peter Baráth is Head of the Department and Manager of Proteomic Core at Bratislava, Slovakia. He is a trained biochemist interested in qualitative and quantitative analysis of diverse proteomes and regulatory roles of protein post-translational modifications.

Namik Rashydov

Namik Rashydov is Head of Laboratory and a Principal Investigator in Kyiv, Ukraine. He is a radiobiologist currently studying the effects of stress factors on plants. His research also deals with radioecology, the Chornobyl Zone, environmental ecotoxicology, and the biotechnology of fast-growing plants.