This is an early access version, the complete PDF, HTML, and XML versions will be available soon.
Molecular Regulation of Phenylpropanoid and Flavonoid Biosynthesis Pathways Based on Transcriptomic and Metabolomic Analyses in Oat Seedlings Under Sodium Selenite Treatment
1
Key Laboratory of Tibetan Plateau Medicinal Plant and Animal Resources, School of Life Sciences, Qinghai Normal University, Xining 810008, China
2
Academy of Plateau Science and Sustainability, Qinghai Normal University, Xining 810008, China
3
Qinghai South of Qilian Mountain Forest Ecosystem Observation and Research Station, Huzhu 810500, China
4
National Forestry Grassland Qinghai Tibet Plateau Characteristic Forest and Grassland Germplasm Resources Protection and Utilization Engineering Technology Research Center, Xining 810008, China
5
Academy of Agricultural and Forestry Sciences, Qinghai University, Xining 810016, China
*
Author to whom correspondence should be addressed.
Biology 2025, 14(9), 1131; https://doi.org/10.3390/biology14091131
Submission received: 18 July 2025
/
Revised: 9 August 2025
/
Accepted: 20 August 2025
/
Published: 26 August 2025
Simple Summary
This study investigates the effects of varying concentrations of sodium selenite (Na2SeO3) on the growth of oat seedlings, as well as the biosynthesis pathways of phenylpropanoids and flavonoids, utilizing transcriptomics, metabolomics, and physiological and biochemical analyses. The results indicate that the T0.02 (0.02 g/kg Na2SeO3) treatment significantly promoted the growth of oat seedlings. As the concentration of Na2SeO3 increased, levels of proline and soluble sugars increased significantly, while pigment content, peroxidase activity, and the generation rate of superoxide anions decreased significantly. The selenium content in the roots and leaves of oat seedlings increased significantly under the T0.1 treatment (p < 0.05). Additionally, six differential metabolites and 29 differential genes related to the phenylpropanoid synthesis pathway were identified, along with 18 differential metabolites and 13 differential genes associated with the flavonoid synthesis pathway. By integrating transcriptomic and metabolomic analyses, nine key genes (including PAL1, PAL4, CHS2, PAL7, POD3, PAL6, CCR1, CCR4, POD4) regulating the metabolism of the phenylpropanoid and flavonoid biosynthesis pathways were screened. This study offers new insights and genetic resources for exploring the response mechanisms of oats to selenium treatment.
Abstract
Selenium can be absorbed and utilized by plants, influencing their growth by altering their physiological metabolism. In this study, based on plant physiology methods, compared to the CK treatment, the height and leaf length of oat seedlings under the T0.02 (0.02 g/kg Na2SeO3) treatment significantly increased by 18.36% and 15.81%, respectively (p < 0.05). Under the T0.1 (0.1 g/kg Na2SeO3) treatment, the levels of malondialdehyde (MDA), proline, soluble sugar content, and peroxidase (POD) activity significantly increased (p < 0.05). However, the seedling height and leaf length under the T0.1 treatment significantly decreased by 33.24% and 23.25%, respectively. Additionally, the contents of chlorophyll a, chlorophyll b, and carotenoids, as well as ascorbate peroxidase (APX) activity and the superoxide anion radical generation rate (O2−) significantly decreased (p < 0.05). The total selenium, organic selenium, and inorganic selenium contents, as measured by the atomic fluorescence spectroscopy method, were also increased in oat seedling roots and leaves under T0.1 treatment (p < 0.05). Selenium had a high coefficient of mobility from root to leaf of 6.01 under T0.02 and 4.65 under T0.1 treatment, and from soil to leaf of 4.98 under T0.02 and 4.55 under T0.1 treatment. Through untargeted metabolomics, six differential phenylpropanoid compounds and 18 differential flavonoid compounds were found in oat seedlings. Based on transcriptomic analysis of oat seedlings, 29 DEGs associated with phenylpropanoid metabolism and 13 DEGs related to flavonoid biosynthesis were identified. Over 60% of the genes (25/42) in the phenylpropanoid and flavonoid biosynthesis pathway were associated with the accumulation of about 74% (20/27) of the compounds in oat leaves. Based on transcriptomic and metabolomics analysis, there were nine major genes (including PAL1, PAL4, CHS2, PAL7, POD3, PAL6, CCR1, CCR4, POD4) modulating the metabolism of phenylpropanoid and flavonoid biosynthesis pathway. This study offers novel insights and genetic resources for exploring the mechanisms underlying plant responses to selenium treatment, thereby further enhancing selenium tolerance in plants.
