Transcriptome analysis of an albino mutant in Haworthia cooperi var. pilifera

Photosynthetic organisms appear green due to the accumulation of chlorophyll (Chl) pigments in their chloroplasts. Although the genes encoding key enzymes related to Chl biosynthesis have been well characterized in herbaceous plants, such as rice, Arabidopsis and maize, white leaf mutants have not yet been fully studied in succulent plants. In this work, we explored the molecular mechanism of leaf color formation in an albino mutant (HUA) of Haworthia cooperi var. pilifera. We investigated the differentially expressed genes (DEGs) between HUA and control plants (wild type, LV) by transcriptome sequencing. Approximately 2,586 genes (1,996 downregulated and 590 upregulated) were found to be differentially expressed in HUA compared with LV using a threshold of ratio change [≥] 2 and false discovery rate (FDR) [≤]0.05. GO analysis predicted that these DEGs participate in 12 cellular component, 20 biological process and 13 molecular function terms. Among the DEGs were well-recognized genes associated with chloroplast division and the biosynthesis of plant pigments, including chlorophyll, carotenoids and anthocyanin, as well as various transcription factor families. Overall, these results can help confirm the molecular regulatory mechanisms controlling leaf pigmentation and provide a comprehensive resource for breeding colorful leaf phenotypes in succulent plants.