Limited selenium (Se) accumulation in agricultural products contributes to widespread dietary Se deficiency, posing a global nutritional threat. Efficient agronomic strategies to enhance Se biofortification in crops are still lacking. Here, we reveal the synergistic effects of shading and Se nanoparticles application on Se biofortification in tea leaves. Field experiments demonstrate that shading enhances Se accumulation in tea leaves under sufficient Se supply, through activating Se metabolism pathway. We identify CsAPR1 functions at the early stage of Se assimilation, catalyzing the reduction of Se (VI). The transcription of CsAPR1 is activated by CsMYB7-like and is further promoted by shading through interaction with CsbHLH70. Under sunlight, CsHY5 competes with CsbHLH70 for binding to CsMYB7-like, thereby attenuating CsMYB7-like-mediated transcription of CsAPR1 and suppressing Se accumulation in tea plants. Our findings reveal the molecular mechanisms underlying shade-induced enhancement of Se biofortification, offering insights and strategies for Se-enriched crop production.

To elucidate the chemical basis underlying bitterness and astringency modulation in jasmine tea, four green tea bases and their corresponding jasmine teas were analyzed using weighted gene co-expression network analysis (WGCNA) combined with spiking validation experiments. WGCNA revealed that catechin, gallocatechin gallate, aspartic acid (Asp), glutamic acid (Glu), arginine (Arg), and alanine (Ala) were positively associated with sweetness and umami but negatively associated with bitterness and astringency. Spiking experiments showed that taste modulation was both concentration- and matrix-dependent. Glu and Asp effectively reduced bitterness at suitable concentrations, whereas the effects of theanine and Arg varied among tea matrices. Bitterness and astringency of jasmine tea infusion are modulated by the combined effects of the chemical matrix of tea base, providing a theoretical basis for tea-base selection and jasmine tea flavor optimization.