Different light qualities modify morphology and expression of CsLHY in in vitro plantlets of Camillia sinensis

Abstract

High yield is one of the core standards of elite tea cultivars. LHY, a key component of the circadian clock, controls various biomass metabolic and developmental processes; and light is a crucial environmental factor that regulates biomass metabolism and modulates plant development and growth. Therefore, in the present study, we evaluated the effect of different light qualities via light-emitting diode (LED) on the morphogenesis and expression of CsLHY by qRT-PCR in in vitro tea plantlets. The findings suggested that the red light had an effect on bud outgrowth, blue light stimulated the content of carotenoids and significantly higher expression level of CsLHY, and far-red light dramatically suppressed the expression of CsLHY and lead to the elongation of internode and small leaf areas. The tentative correlations between the phenotypic responses and expression of CsLHY under different light qualities were discussed, which involved multiple light signaling pathways including phytochrome or cryptochrome, and auxin signaling. Besides the novel discoveries on the connections between light quality and the growth of in vitro tea plantlets, the experimental approach in this study could serve as a practical tool for induced and directed growth of tea plantlets and other in-depth study of gene function upon such light treatment.