Gene Expression in Delphinidin-Based Anthocyanin Level in Wild Chicory (Cichorium intybus) Flowers

Background/Objectives: Wild chicory (Cichorium intybus L.) is a widespread species that produces blue flowers, helping to add colour to meadows in both natural and human-altered environments, while plants with white flowers are rare in nature. This species plays a significant ecological role and has given rise to cultivated horticultural varieties, while retaining culinary and medicinal value in its wild form. From a biochemical perspective, the synthesis and accumulation of anthocyanins are significant characteristics; however, there is a lack of published data on the genes involved in these processes within the vegetative and floral organs of wild chicory. The study aims to identify candidate structural genes and regulatory factors that may be involved in a white-flower phenotype and to determine whether alterations in the expression of genes associated with anthocyanin biosynthesis contribute to the absence of floral pigmentation. Methods: In this study, a set of genes encoding biosynthetic enzymes and regulatory factors was isolated. Their sequences and transcription levels were evaluated, with particular attention paid to the corollas of flowers from both the common blue and the rare white-flowered forms. Morphological analyses of the floral organs were conducted to identify differences between these forms, while a genetic analysis was performed to clarify the inheritance of the colourless flower trait. Results: Plants with white flowers lack anthocyanins in both their floral and vegetative tissues. The results revealed a distinct gene expression profile between the two morphotypes. In white flowers, expression levels of the Anthocyanidin synthase (ANS) and Flavonoid 3′,5′-hydroxylase (F3′5′H) genes were markedly reduced, along with a significant decrease in the activity of the bHLH-like regulatory gene. The colourless flower trait was consistent with monogenic recessive inheritance. Conclusions: In wild chicory, the white-flowered mutant may be attributable to a putative transcriptional dysregulation of the anthocyanin biosynthetic pathway. However, it will be necessary to analyse the regulatory regions and promoters of differentially expressed genes. Genome-wide transcriptomic approaches will be useful for identifying and reconstructing the complete gene network involved in anthocyanin biosynthesis.