Mengyao Nie

Ethylene (ET) influences the synthesis of anthocyanins, although its regulatory effects can differ significantly across various plant species. In apples (Malus domestica), ET promotes anthocyanin synthesis, whereas in Arabidopsis thaliana, it inhibits its accumulation. Our research showed that ethephon (Eth), an ET derivative, promotes anthocyanin synthesis in ‘Viviana’ lilies, which has great potential in the cut flower industry. The regulatory mechanism whereby ET influences anthocyanin synthesis in lilies remains unclear. In this study, we screened and characterized an ET-induced ET response factors (ERFs), LvERF113, with inhibitory function. Our analyses suggested that LvERF113 could inhibit the negative regulatory function of LvMYB1 at transcriptional and posttranslational levels, promoting anthocyanin synthesis in ‘Viviana’ lily tepals. In addition, LvERF113 is positively regulated by LvMYB5, forming the LvMYB5-LvERF113-LvMYB1 module controlling anthocyanin synthesis by ET in ‘Viviana’ lily. These findings offer new insights into the ET regulatory network of anthocyanin synthesis and provide a theoretical basis for the application of ET derivatives in the cut flower industry.

Lily (Lilium spp.), a horticultural crop serving both ornamental and edible functions, derives its coloration primarily from anthocyanins. However, limited studies have been conducted on the accumulation of anthocyanins within lilies. In this study, we cloned a light-induced transcription factor named as LvBBX24 in lilies. Through genetic and biochemical analysis, we determined that LvBBX24 could upregulate the transcription of LvMYB5 and facilitate anthocyanin synthesis. Moreover, we identified that darkness promoted the degradation of LvBBX24 protein. Through screening a yeast library, we identified LvbZIP44 acts as its interacting partner. Genetic testing confirmed that LvbZIP44 also plays a role in promoting lily anthocyanin synthesis. This indicates a potential synergistic regulatory effect between LvBBX24 and LvbZIP44. Our study indicates that LvBBX24 and LvbZIP44 cooperate to regulate anthocyanin accumulation in lily petals. These findings provide compelling evidence supporting the idea that LvBBX24 and LvbZIP44 may form a looped helix surrounding the LvMYB5 promoter region to regulate anthocyanin biosynthesis.