Effect of non-thermal plasma (NTP) on common sunflower (Helianthus annus L.) seed growth via upregulation of antioxidant activity and energy metabolism-related gene expression

Abstract

In recent years, non-thermal plasma (NTP) technology has been extensively applied in medical, environmental, biological, and agricultural fields. The sunflower (Helianthus annus L.) is valued by farmers as a relatively common, economically valuable agricultural crop. In this study, our purpose was to use NTP technology to identify suitable conditions to promote sunflower seed germination and seedling growth, and to elucidate the mechanism of action. Our research found that 16.8 kV treatment for 15 s had the greatest effect on seed germination and growth in Chinese sunflower seeds. Interestingly, American sunflower seeds were not sensitive to this treatment. NTP treatment increased the concentration of solubilized protein, antioxidant enzyme activity and expression, and adenosine triphosphate (ATP) production. It also upregulated ATPa2, ATPb1-3, the target of rapamycin (TOR), and growth-regulating factors (GRF) 1-3 and 6, while it downregulated ATPMI25 mRNA expression in 14-day-old sunflower leaves. These results indicate that argon NTP promoted sunflower seed germination and growth by regulating superoxide dismutase 2 (SOD2), catalase (CAT), ATP, TOR, and GRFs. Transcriptome analysis showed that various key genes are involved in starch and sucrose metabolism, pentose and glucoronate interconversions, DNA replication, and plant hormone signal transduction. Our analysis provides comprehensive gene expression information at the transcriptional level, which lays the foundation for further analysis of the function of candidate genes required for the development and growth of sunflower, and contributes to the understanding of the molecular mechanism of sunflower growth.