The Effects of the Light Spectral Composition on the Development of Olive Tree Varieties Mediated by Photoreceptors

Plants have the ability to perceive a wide range of light spectra, from which they derive not only the energy required for photosynthesis but also a variety of environmental cues and signals mediated by specific photoreceptors that trigger a cascade of biochemical reactions essential for their development. The olive tree (Olea europaea L.) is a woody species for which, despite its agronomic and economic relevance, the influence of light on its development remains poorly understood. The present study, a combined approach was employed, involving the phenotyping of 10 different cultivars exposed exclusively to red light (RL) and blue light (BL) for a period of two months, in addition to the monitoring of expression profiles of 10 photoreceptor-encoding genes in two of the cultivars that exhibited the most contrasting responses to the different light conditions. Our results revealed a correlation between the expression of specific genes and the differential response to exclusive exposure to the two light spectra, highlighting a generally enhanced photosynthetic activity of nearly all cultivars to blue light (BL) and, conversely, a negative response to red light (RL). Taken together, our data, by elucidating the response of the olive to specific light spectra and the underlying molecular mechanisms, pave the way for further studies on these traits, which could be useful for the improvement of this species.