LAUSR

BACKGROUND Selenium (Se) is an increasing concern for the investigators predominantly because of its consumption in the human body mainly from crops. As the fourth largest plant crop globally, alfalfa is one of the most important forages. Alfalfa was fertilized with selenite (Se IV) under field conditions to study the accumulation and assimilation of Se (IV) and to assess the impact of Se fertilization. RESULTS It was analyzed that the physio-biochemistry, Se speciations, combined with transcriptome after spraying Se (IV) at different times (0, 12, and 48 h). 9,402 and 12,607 differentially expressed genes (DEGs) were identified at 12 h (vs 0 h) and 48 h (vs 12 h). DEG functional enrichments proposed two time-specific biological processes: Se (IV) accumulation was the primary process at 0-12 h, and its assimilation mainly occurred during 12-48 h. This was further proved by the separation of various Se speciations at different times. It showed that Se-supplementation also affected the soluble protein, soluble sugar, pigment contents and antioxidant capacity. Se-biofortification could improve the stress resistance of alfalfa by enhancing antioxidant system to scavenge ROS (e.g., hydrogen peroxide) and boosting carbohydrate metabolism. CONCLUSION By integrating physio-biochemistry, Se-related metabolites, and transcriptome under Se (IV) treatment, this study provides data to guide further work on Se-fortification in alfalfa. This article is protected by copyright. All rights reserved.