How do light environment and genotype modulate the physiological network involved in branching control?

Light environment and genotype

How do light environment and genotype modulate the physiological network involved in branching control?

Light plays a determining role in the acquisition of the aerial architecture of the plant. It acts in a complex way, both by its quantity and quality, and with immediate or non-immediate effects (role of the light history of the plant). Our goal is to understand the regulatory network by which light, in these different components, controls branching initiation at the plant scale (Schneider et al., 2019) and its interaction with genotype. We study the impact of light both locally at the axillary bud level and globally through its action on nutrient and hormone fluxes within the plant. We adopt an approach combining physiology, ecophysiology, and modeling.

So far, our research on the effect of light quantity has shown correlations between the effect of light intensity on bud break and the levels of sugars and cytokinins, two stimulators of bud break (Roman et al., 2016; Corot et al., 2017). We have experimentally demonstrated an effective role of cytokinins in this regulation. Local light in the vicinity of the bud stimulates cytokinin production in the stem, which allows bud break. On the other hand, the effective role of sugars has not yet been established because of the difficulty to manipulate them at the plant level. Our current research aims at using a model of sugar management by the plant and of the response of the bud to its local environment to understand the relative contribution of sugars and cytokinins. More recently, we have also undertaken to study the effect of light quality on branching in interaction with genotype. Initial results showed a strong genotype x light quality interaction, as previously demonstrated for other environmental factors, such as water supply (Crespel et al., 2014, 2020; Li-Marchetti et al. (2015). Year-specific QTLs (Quantitative Trait Loci) - co-localizing with BRC1 - have been identified (Li-Marchetti et al. 2017). They would be at the origin of the genotype x year interactions observed in rose.

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Modification date : 04 December 2023 | Publication date : 15 December 2020 | Redactor : stragene