7th Asia-Pacific Conference on Plasma Physics, 12-17 Nov, 2023 at Port Messe Nagoya

Impact of plasma irradiation on plant seeds metabolism

Takamasa Okumura1,2, Pankaj Attri2, Yushi Ishibashi3, Kazunori Koga1,2, and Masaharu Shiratani1,21Faculty of Information Science and Electrical Engineering, Kyushu University
2
Center of Plasma Nano-interface Engineering, Kyushu University
3
Faculty of Agriculture, Kyushu University
e-mail (speaker): t.okumura@plasma.ed.kyushu-u.ac.jp
Effects of plasma irradiation on seed response hasgarnered considerable attention [1], particularly for its
role in enhancing germination and overall growth stages[2-5]. Recently, molecular biological studies haverevealed plasma irradiation enhances germination andthese responses correlated with a decrease in abscisicacid (ABA) and an increase in gibberellin (GA) content[6, 7]. Additionally, plasma irradiation increases in GA
content and induces long-lasting effects on leaf gene
expression and stimulates the expression of proteinsprimarily involved in photosynthetic processes and theirregulation [8]. Thus, plasma irradiation to seeds affects
their metabolisms and induces phenotypes and omics
responses.
The gene-level studies of plasma irradiation to seeds
have shed light on some of the mechanisms underlying
such effects [1]. Plasma-irradiated seeds show
improvement of germination characteristics, anddownregulation of genes involved in ABA biosynthesis,
whereas upregulation of genes involved in ABA
catabolism and α-amylase biosynthesis [9]. Further,plasma irradiation caused significant hypermethylationof the NCED5 promoter and hypomethylation of Amy1C
and Amy3E promoters, which matched their expression
patterns. These results show that plasma irradiation toseeds allows us to regulate epigenetics, altering DNA
methylation (Fig. 1).
It is important to be conducted the quantitativeevaluation of the number of plasma-induced particles(Reactive oxygen and nitrogen species (RONS), photons,ions, etc.) supplied into the seeds to understand themechanism of plasma irradiation effects. Mass
spectrometry provided experimental evidence that nitrateion, NO3−, is introduced in seeds as RONS upon

irradiation with plasma [10]. NO3− in plant seeds is
responsible for inducing responses such as dormancy
break, gene expression regulation, signal transduction,and ABA metabolism resulting from NLP8 binding to theCYP707A2 promoter. In the future, we will quantitatively
investigate the biological responses based on thephysical quantities of factors that plasma irradiation
exerts on seeds.
In the presentation, we will discuss the research fromthe viewpoint of plant metabolism, including the latest
results.
Acknowledgements
This work was supported by JSPS-KAKENHI
JP20H01893, JP19K14700, JP22K03586, JP19H05462,
JP21H04451, JP20K14454, and A-STEP JPMJTR20RU,
JSPS Core-to-Core Program JPJSCCA2019002, Plasma
Bio Consortium, and Center for Low-Temperature
Plasma Sciences, Nagoya University.
References[1] P. Attri et al., Processes 8(8), 1002 (2020).
[2] S. Kitazaki et al. Curr. Appl. Physics. 14 (2014).
[3] K. Koga et al., Appl. Phys. Express. 9 (2015).
[4] K. Kazunori et al., Jpn. J. Appl. Phys. 59 SHHF01(2020).
[5] H. Hashizume et al., Plasma Process. Polym. 18, 1,2000181 (2021).
[6] Laima Degutyt ė -Fomins et al., 59, SH1001 (2020).
[7] P. Attri et al., Sci Rep 11, 2539 (2021).
[8] V. Mildaziene et al., Sci. Rep. 9 (2019).
[9] C. Suriyasak et al., ACS Agricultural Science &Technology, 1, 1, (2021).
[10] T. Okumura et al., Sci Rep 12 (2022).

Fig. 1. (a) Conceptual diagram of DNA methylation alteration in promotor of gemination-related genes of rice seeds byplasma irradiation and (b) recovery of degraded germination characteristics of heat-stressed seeds by plasma irradiation.