Cloning and functional analysis of transcription factor AaCMB1 on carotenoid accumulation in spathe of Anthurium andraeanum.

Abstract

Anthurium andraeanum Linden, a flowering foliage plant belonging to the Araceae family, exhibits colorful spathes but lacks deep yellow cultivars. The carotenoid metabolic pathway is crucial for the accumulation of yellow pigments (e.g. lutein) in plant cells, with transcriptional regulation playing a key role in this process. Among these regulators, the MADS-box family represents one of the major transcription factor families involved in this regulatory network. To investigate the regulatory role of MADS-box family transcription factors in carotenoid metabolism in Anthurium spathes, a MADS-box gene from the light yellow spathe cultivar 'Vanilla' was cloned and designated as AaCMB1. Subcellular localization analysis revealed that AaCMB1 is localized in the nucleus. Transient overexpression of AaCMB1 increased carotenoid accumulation in Anthurium spathes, and quantitative real-time polymerase chain reaction (qRT-PCR) analysis showed that overexpression of AaCMB1 upregulated the expression of key structural genes in the carotenoid biosynthetic pathway. Yeast two-hybrid and bimolecular fluorescence complementation (BiFC) assays demonstrated that AaCMB1 interacts with AaNAC1574. Yeast one-hybrid and dual-luciferase reporter assays further indicated that AaCMB1 can activate the AaLCYB promoter. These findings suggest that AaCMB1 and AaNAC1574 may form a heterodimer to regulate the expression of AaLCYB, thereby modulating carotenoid accumulation in Anthurium spathes.