Molecular and physiological response of chives (Allium schoenoprasum) under different concentrations of selenium application by transcriptomic, metabolomic, and physiological approaches

Selenium (Se) is a vital trace element for human health, and its uneven distribution in soil triggers Se deficiencies in some regions. Se biofortification has been demonstrated to mitigate this issue by producing Se-enriched crops. Chives (Allium schoenoprasum cv. 'sijixiaoxiangcong'), a simple-to-cultivate and fast-growing vegetable, offers a promising Se-accumulation ability. However, the physiological and molecular mechanisms underlying Se responses in chives remain unclear. This study applied sodium selenite at various doses to chives via root irrigation, and integrated strategies including multi-omics were employed to unfold the response mechanism. (1) Physiological data reveal that sodium selenite irrigation adversely affects the height, shoot weight, chlorophyll, and soluble sugar content of chives' aerial parts. However, chives exhibit a remarkable ability to accumulate selenium, reaching up to 40.21 mg kg(-1) DW under high Se exposure (160 mg L-1); (2) Transcriptomic analysis revealed significant enrichment of the phenylpropanoid biosynthesis and plant hormone signal transduction pathways under Se treatment. Key DEGs, such as MAPKKK17_18, JAZs, and PCL, were identified as Se response candidates. Our findings show that selenomethionine is the primary form of Se accumulation, and DEGs linked to antioxidant defense and phenylpropanoid biosynthesis are crucial for mitigating Se stress; (3) Importantly, plant hormone signaling plays a central role by regulating phenylpropanoid metabolism and enhancing the antioxidant enzyme system, highlighting its significance in chives' Se tolerance. These results clarify the Se response mechanisms in chives and enable Se-enriched chive cultivation.