The TIFY family, known as a novel group of transcription factors unique to the plant, plays a number of roles and has been functionally characterized in numerous plant species. However, TIFY proteins remain unexplored in litchi. Here, we identified 14 TIFY genes in litchi, which were unevenly located on 8 of 15 chromosomes. All of the LcTIFY proteins were predicted to be nuclear-localized and were phylogenetically categorized into four subfamilies (TIFY, PPD, ZML, and JAZ). Duplication analysis detected no tandem duplications but identified one segmental duplication event with LcTIFY genes, suggesting that segmental duplication served as the primary driving force for the expansion of LcTIFY genes. Comparative collinear analysis revealed 12, 5, and 27 collinear gene pairs between litchi and Arabidopsis, rice, and apple, respectively, providing valuable clues for understanding the evolution of the LcTIFY genes. RNA-Seq and qRT-PCR analyses indicated tissue-preferential expression patterns among LcTIFY genes. Notably, LcPPD1 and LcJAZ5 expressions were negatively correlated with anthocyanin accumulation in the ‘Feizixiao’ variety, except that LcJAZ5 displayed a positive correlation under CPPU treatment. In contrast, LcJAZ7 expression showed a positive correlation across all treatments, implicating these genes in the regulation of pericarp pigmentation. Collectively, these findings lay the groundwork for future investigations into the functional roles of TIFY genes in litchi and offer valuable genetic resources for elucidating the mechanisms underlying litchi pigmentation, thereby providing fresh perspectives for subsequent research into the molecular mechanisms of color formation in plants.
Tang et al. (Mon,) studied this question.