Biology subjects

Olas, J. J.

Publications and source records attributed to Olas, J. J..

4 recordsLinked to original sources

bioRxiv2024

FLOWERING LOCUS C integrates carbon and nitrogen signaling for the proper timing of flowering in Arabidopsis

The timing of flowering in plants is modulated by both carbon (C) and nitrogen (N) signaling pathways. In a previous study, we established a pivotal role of the sucrose-signaling trehalose 6-phosphate pathway in regulating flowering under N-limited short-day conditions. In this work, we expand on our finding that wild-type plants grown under N-limited short days require an active trehalose 6-phosphate pathway to be able to flower. Both wild-type plants grown under N-limited conditions and knock-down plants of TREHALOSE PHOSPHATE SYNTHASE1 induce FLOWERING LOCUS C expression, a well-known floral repressor associated with the vernalization response. When exposed to an extended period of cold, a mutant of FLOWERING LOCUS C fails to respond to N availability, and flowers at the same time under N-limited and full-nutrition conditions. Our data suggest that SUCROSE NON-FERMENTING 1 RELATED KINASE 1-dependent trehalose 6-phosphate-mediated C signaling and a novel mechanism downstream of N signaling likely involving NIN-LIKE PROTEIN 7 impact the expression of FLOWERING LOCUS C. Collectively, our data underscore the existence of a multi-factor regulatory system in which both C and N signaling pathways jointly govern the regulation of flowering in plants.

plant biology↗

bioRxiv2022

Transcription factor HSFA7b controls ethylene signaling and meristem maintenance at the shoot apical meristem during thermomemory

The shoot apical meristem (SAM) is responsible for overall shoot growth by generating all above-ground structures. Recent research identified that the SAM displays an autonomous heat stress (HS) memory of a previous non-lethal HS event. Considering the importance of the SAM for plant growth it is essential to unlock how its thermomemory is mechanistically controlled. Here, we report that HEAT SHOCK TRANSCRIPTION FACTOR A7b (HSFA7b) plays a crucial role in this process in Arabidopsis. We found that HSFA7b directly regulates ethylene response at the SAM by binding to promoters of key regulators of ethylene signaling including ETHYLENE-INSENSITIVE 3 to establish thermotolerance. Moreover, HSFA7b controls maintenance of the SAM stem cell pool during thermomemory by regulating the expression of the master regulator WUSCHEL through direct transcriptional activation of the SPLAYED chromatin remodelling factor.

plant biology↗

bioRxiv2020

Primary carbohydrate metabolism genes participate in heat stress memory at the shoot apical meristem of Arabidopsis thaliana

Although we have a good understanding of the development of shoot apical meristems (SAM) in higher plants, and the function of the stem cells (SCs) embedded in the SAM, there is surprisingly little known of its molecular responses to abiotic stresses. Here, we show that the SAM of Arabidopsis thaliana senses heat stress (HS) and retains an autonomous molecular memory of a previous non-lethal HS, allowing the SAM to regain growth after exposure to an otherwise lethal HS several days later. Using RNA-seq, we identified genes participating in establishing a SAM-specific HS memory. The genes include HEAT SHOCK TRANSCRIPTION FACTORs (HSFs), of which HSFA2 is essential, but not sufficient, for full HS memory in the SAM, the SC regulators CLAVATA1 (CLV1) and CLV3, and several primary carbohydrate metabolism genes, including FRUCTOSE-BISPHOSPHATE ALDOLASE 6 (FBA6). We found that expression of FBA6 during HS at the SAM complements that of FBA8 in the same organ. Furthermore, we show that sugar availability at the SAM is essential for survival at high-temperature HS. Collectively, plants have evolved a sophisticated protection mechanism to maintain SCs and, hence, their capacity to re-initiate shoot growth after stress release.

plant biology↗

bioRxiv2020

The role of trehalose 6-phosphate in shoot branching - local and non-local effects on axillary bud outgrowth in arabidopsis rosettes

- Trehalose 6-phosphate (Tre6P) is a sucrose signalling metabolite that has been implicated in regulation of shoot branching, but its precise role is not understood. - We expressed tagged forms of TREHALOSE-6-PHOSPHATE SYNTHASE1 (TPS1) to determine where Tre6P is synthesized in arabidopsis (Arabidopsis thaliana), and investigated the impact of localized changes in Tre6P levels, in axillary buds or vascular tissues, on shoot branching in wild-type and branching mutant backgrounds. - TPS1 is expressed in axillary buds and the subtending vasculature, as well as in the leaf and stem vasculature. Expression of a heterologous trehalose-6-phosphate phosphatase (TPP) to lower Tre6P in axillary buds strongly delayed bud outgrowth in long days and inhibited branching in short days. TPP expression in the vasculature also delayed lateral bud outgrowth and decreased branching. Increased Tre6P in the vasculature enhanced branching and was accompanied by higher expression of FLOWERING LOCUS T (FT) and up-regulation of sucrose transporters. Increased vascular Tre6P levels enhanced branching in branched1 but not in ft mutant backgrounds. - These results provide direct genetic evidence of a local role for Tre6P in regulation of axillary bud outgrowth within the buds themselves, and also connect Tre6P with systemic regulation of shoot branching via FT.

plant biology↗