Mechanism of sugarbeet seed germination enhanced by hydrogen peroxide

Authors: Chu, Chenggen; Poore Fonseka, Rachael; Bolton, Melvin; Fugate, Karen

Submitted to: Frontiers in Plant Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 3/28/2022
Publication Date: 4/25/2022
Citation: Chu, C.N., Poore, R.C., Bolton, M.D., Fugate, K.K. 2022. Mechanism of sugarbeet seed germination enhanced by hydrogen peroxide. Frontiers in Plant Science. 13. Article e888519. https://doi.org/10.3389/fpls.2022.888519.
DOI: https://doi.org/10.3389/fpls.2022.888519

Interpretive Summary: Seed germination is a critical first stage of plant development but can be arrested by factors including dormancy and environmental conditions. Strategies to enhance germination are of interest to plant breeders to ensure the ability to utilize the genetic potential residing inside a dormant seed. In this study, we developed a germination protocol using hydrogen peroxide (H2O2) to significantly improve the germination percentage of sugarbeet seeds. Gene expression analysis indicated that H2O2 quickly transits seeds from dormancy into germination by accelerating the degradation of expressed genes stored inside the seed and promoting the expression of genes involved in cellular activities toward cell growth and proliferation. The research provides new knowledge about the role of external added H2O2 acting as a signaling molecule for regulating gene activities during germination. Moreover, the germination protocol developed in this research will be useful for rescuing plant germplasms with poor germination.

Technical Abstract: Seed germination is a critical first stage of plant development but is often limited by dormancy and environmental conditions. Strategies to enhance germination are of interest to plant breeders to ensure the ability to utilize germplasms and successful generation advancement during breeding. In this study, germination of two sugarbeet (Beta vulgaris ssp. vulgaris L.) lines F1004 and F1015 through incubating seeds in hydrogen peroxide (H2O2) solution was improved over 70% relative to germinating seeds through water incubation. It was further found that low germination from water incubation was caused by physical dormancy in F1015 seeds that initial seed imbibition is blocked by seed pericarp, and physiological dormancy in F1004 seeds that germination is compromised due to physiological condition of embryo. To identify genes that are differentially expressed in response to cellular activities promoted by H2O2 during overcoming different type of dormancies, an RNA-Seq study was carried out and found H2O2 treatment during germination accelerated the degradation of seed stored mRNAs that were synthesized before or during seed storage to provide protections and maintain the dormant state. Comparison of transcripts in H2O2-treated seeds between two sugarbeet lines identified differentially expressed genes (DEGs) with higher levels in F1004 for alleviating physiological dormancy were known to relative to gene expression regulation. The research established that H2O2 overcomes both physical and physiological dormancies through quickly transition seeds from dormancy into germination. More DEGs relative to gene expression regulation involved in relieving physiological dormancy provides new knowledge about the role of exogenous H2O2 as a signaling molecule for regulating gene activities during germination. Moreover, the protocol using H2O2 to promote germination will be useful for rescuing plant germplasms with poor germination.