Biology subjects

Ince, Y.

Publications and source records attributed to Ince, Y..

2 recordsLinked to original sources

bioRxiv2026

Photosynthesis-derived carbon gates cell cycle activation to enable hormone-autonomous shoot regeneration

Shoot regeneration is a powerful model for cell fate reprogramming but how it occurs in nature remains poorly understood because studies in Arabidopsis thaliana conventionally rely on in vitro assays supplemented with exogenous hormones and sugars. In this study, we established the Hormone-autonomY Direct Regeneration Assay (HYDRA) in which removal of the shoot apical meristem (SAM) initiates shoot regeneration from the cotyledon-hypocotyl boundary domain without hormone or sugar supplementation. We show that photosynthesis-derived carbon and the boundary domain are two separable but convergent requirements for shoot regeneration in HYDRA. Carbon availability increases in the boundary domain where it activates cell cycle progression via the RETINOBLASTOMA-RELATED1 (RBR1) pathway. Carbon deprivation blocks regeneration despite induction of SAM marker genes, indicating that carbon-dependent cell cycle activation is a limiting factor for regeneration. In parallel, perturbation of the boundary domain or its regulators reduces regeneration despite sufficient carbon, indicating that boundary domain identity is independently required. Additionally, exogenous carbon supply overcomes the requirement for SAM removal to induce shoot formation, indicating that carbon availability also acts as an initiation cue. Together, this study reveals an inherent capacity for hormone-autonomous shoot regeneration and identifies photosynthesis-derived carbon as a central regulator of this process.

Plant Biology↗

bioRxiv2021

Reduced light access promotes hypocotyl growth via autophagy-mediated recycling

Plant growth ultimately depends on fixed carbon, thus the available light for photosynthesis. Due to canopy light absorption properties, vegetative shade combines reduced light and a low red to far-red ratio (LRFR). In shade-avoiding plants, these two conditions independently promote growth adaptations to enhance light access. However, how these conditions, differing in photosynthetically-available light, similarly promote growth remains unknown. Here, we show that Arabidopsis seedlings adjust metabolism according to light conditions to supply resources for hypocotyl growth enhancement. Transcriptome analyses indicate that reduced light induces starvation responses, suggesting a switch to a catabolic state to promote growth. Accordingly, reduced light promotes autophagy. In contrast, LRFR promotes anabolism including biosynthesis of plasma-membrane sterols downstream of PHYTOCHROME-INTERACTING FACTORs (PIFs) acting in hypocotyls. Furthermore, sterol biosynthesis and autophagy are indispensable for shade-induced hypocotyl growth. We conclude that vegetative shade enhances hypocotyl growth by combining autophagy-mediated recycling and promotion of specific anabolic processes. HIGHLIGHTSO_LIReduced light and LRFR induce catabolism and anabolism, respectively C_LIO_LIReduced light promotes autophagy to enhance hypocotyl growth in vegetative shade C_LIO_LILRFR enhances hypocotyl growth by promoting plasma membrane lipid biosynthesis C_LIO_LIIn LRFR, PIFs promote sterol biosynthesis specifically in the hypocotyl C_LI

plant biology↗