BBX Genes of Cymbidium ensifolium Exhibited Intense Response to Blue Light in Meristem Induction through Artificial Control

Abstract

Cymbidium ensifolium, a prominent orchid species, is both highly valued for its ornamental qualities and commercially cultivated. However, the species has a considerable challenge in its breeding efforts due to the lengthy period of 7–8 years required for it to transition from seed germination to flowering. BBXs are multifunctional proteins that modulate the actions of critical regulators including HY5 and COP1 in response to blue light, ultimately impacting photomorphogenic processes. In this study, BBX proteins, known for their essential roles in regulating developmental processes under various light conditions, were chosen as the main subject of investigation. The outcome reveals the presence of 19 BBX genes in their genome. The genes are classified into four separate clades and dispersed among 12 out of the 20 chromosomes. Located in the nuclear, physicochemical properties of proteins, analysis of the promoter region reveals the existence of almost 800 cis-acting elements, highlighting the complex regulatory mechanisms that control the expression of the CeBBXs in various organs, as well as their response to light and hormone inputs. Moreover, the examination of differential expression under blue light therapy reveals their involvement in photomorphogenic reactions. The expression of CeBBXs exhibits substantial alterations as the duration of exposure to blue light increases. These findings contribute to a deeper understanding of the roles that BBX genes serve in C. ensifolium, providing a basis for future studies on the functions and regulatory mechanisms of BBX members in the context of floral initiation and development within this species.