Arabidopsis thaliana rosette habit is controlled by combined light and energy signaling converging on transcriptional control of the TALE homeobox gene ATH1

Abstract

In the absence of light signals, Arabidopsis plants fail to develop the rosette habit typical for this species. Instead, plants display caulescent growth due to elongation of rosette internodes. This aspect of photomorphogenic development has been paid little attention and molecular events involved, downstream of photoreceptor signaling, remain to be identified.Using a combination of genetic and molecular approaches, we show that Arabidopsis rosette habit is a photomorphogenic trait controlled by induction of ARABIDOPSIS THALI-ANA HOMEOBOX GENE1 (ATH1) as downstream target of multiple photoreceptors.ATH1 induction prevents rosette internode elongation by maintaining the shoot apical meristem (SAM) rib zone area inactive and requires inactivation of photomorphogenesis inhibitors, including PHYTOCHROME INTERACTING FACTOR (PIF) proteins. ATH1 activity results in tissue-specific inhibition of PIF expression, establishing double-negative feedbackregulation at the SAM. Light-requirement for ATH1 expression can be overcome by high sugar availability to the SAM. Both sugar and light signals that induce ATH1 and, subsequently, rosette habit are mediated by TOR kinase.Collectively, our data reveal a SAM-specific, double-negative ATH1-PIF feedback loop at the basis of rosette habit. Upstream, TOR kinase functions as central hub integrating light and energy signals that control this for Arabidopsis quintessential trait.

Propiconazole and Tianfengsu Regulated the Growth, Flavor, and Nutritionof Brassica rapaby Brassinosteroid Pathway

“…The ARK2 gene, involved in tubulin formation and plant morphogenesis [41,42], and the HEMA2 gene, encoding a key enzyme in the chlorophyll synthesis pathway [43], were also downregulated, potentially contributing to the altered plant architecture and photosynthetic pigment content. On the other hand, the upregulation of the DOGT1 gene, which glucosylates brassinosteroids and leads to a BR-deficient phenotype when overexpressed [44], and the ATH1 gene, a transcription factor involved in photomorphogenesis and flowering time regulation [45, 46], may be responsible for the dwarf and compact phenotype and delayed flowering observed in PCZ-treated choy sum.…”

Martina Legris

“…However, Borniego et al (2022) showed that genes that were described as thermosensors in shoots (phytochrome B, PIF7, EARLY FLOWERING 3) do not fulfil the same function in the root, adding a new layer of complexity to the system and addressing a question that interests me immensely, which is the sitespecificity of signalling cascades. Another recent paper that I particularly liked was Hajibehzad et al (2023), where they evaluated the regulation of the rosette growth habit of Arabidopsis. This paper appealed to me because it addresses an important question, which is how environmental signals control meristem activity.…”