Plasma-driven alteration of plant environmental memory*

Plants have difficulty moving after germination, so they have a high adaptive capacity for environmental change. When parental plants are exposed to temperatures of 30°C or higher during the rice-planting stage, harvested seeds exhibit high-temperature stress through DNA modification in the DNA promotor region of abscisic acid (ABA)-related and α-amilase-related genes, resulting in degraded germination characteristics and rice quality. We have found that several minutes of plasma irradiation improves the germination of the heat-stressed seeds [1]. We found that gene expression related to ABA and α-amylase [1] is changed by altering methylation in the DNA promotors region of ABA (OsABA8′OH3) and α-amylase (OsAmy1C and OsAmy3E) by plasma irradiation. These results show that plasma irradiation to seeds allows us to regulate epigenetics and helps plants adapt to changing environments. These phenomena can be explained by the amount of particles produced by plasmas transferred to the seeds. We found that nitrate ion is introduced in seeds as reactive oxygen and nitrogen species upon irradiation with plasma [2]. The nitrate ions in plant seeds induce responses such as dormancy break, gene expression regulation, signal transduction, and ABA metabolism resulting from NLP8 binding to the CYP707A2 promoter. This method helps to recover from the decline in food productivity caused by global warming and reduces fertilizer consumption.

[1] C. Suriyasak, K. Hatanaka, H. Tanaka, T. Okumura, D. Yamashita, P. Attri, K. Koga, M. Shiratani, N. Hamaoka, and Y. Ishibashi, ACS Agric. Sci. Technol. 1, 5 (2021).

[2] T. Okumura, P. Attri, K. Kamataki, N. Yamashita, Y. Tsukada, N. Itagaki, M. Shiratani, Y. Ishibashi, K. Kuchitsu, and K. Koga, Sci. Rep. 12, 12525 (2022).