Biology subjects

Fernie, A.

Publications and source records attributed to Fernie, A..

6 recordsLinked to original sources

bioRxiv2025

The improved auxin signalling via entire mutation enhances aluminium tolerance in tomato

Acidic soils limit food production in many developing countries by promoting the solubilization of aluminium (Al) cations. Consequently, roots absorb this metal from soil solution, arresting their growth while reducing water and nutrient uptake. To mitigate the impacts of Al, plants rewire their metabolism and growth, with diverse mechanisms in this process shaped by changes in auxin signalling. Here, we present a comprehensive study on the significance of auxin signalling for Al tolerance. We used tomato mutants with reduced (diageotropica, dgt) and increased (entire) auxin sensitivity to assess the regulation of growth and metabolism in plants coping with Al toxicity. Our results indicated a reduced Al tolerance in the dgt mutant, whereas entire was able to tolerate toxic levels of Al. This contrast can be explained by a differential accumulation of reactive oxygen species (ROS) in the root transition zone, where dgt exhibited more differentiated cells, making the pericycle evident. In contrast, entire showed only slight alterations in the transition zone, with root meristematic cells maintaining a reduced level of cell differentiation, which can be associated with sustained growth under toxic Al levels. These differences were followed by alterations in metabolites related to Al sensitivity in the roots of dgt plants, whereas the entire mutant exhibited only slight metabolic changes. Collectively, our results suggest that genetic modifications to regulate auxin perception have the potential to increase Al tolerance in crops.

plant biology↗

bioRxiv2022

DUF581-9 (At2g44670; FLZ3) negatively regulates SnRK1 activity by interference with T-loop phosphorylation

In plants, SUCROSE NON-FERMENTING RELATED KINASE 1 (SnRK1) is a key energy-sensor that orchestrates large-scale transcriptional reprogramming to maintain cellular homeostasis under energy deficit. SnRK1 activity is under tight negative control, although the exact mechanisms leading to its activation are far from being understood. We show that the Arabidopsis DOMAIN OF UNKNOWN FUNCTION (DUF581) protein DUF581-9/FLZ3 binds to the catalytic SnRK1 subunit KIN10 to inhibit its activation by GRIK-dependent T-loop phosphorylation. Overexpression of DUF581-9 in Arabidopsis dampens SnRK1 signalling and interferes with adaptation to dark-induced starvation. The presence of DUF581-9 significantly reduced SnRK1 activity in protoplasts and in vitro. This was accompanied by a reduction in T175 T-loop phosphorylation and also diminished KIN10 auto-phosphorylation. Furthermore, DUF581-9 reduced binding of the up-stream activating kinase GRIK2 to KIN10, explaining the reduced KIN10 T-loop phosphorylation. Ectopically expressed DUF581-9 protein was rapidly turned over by the proteasome when Arabidopsis plants were subjected to starvation treatment, likely releasing its inhibitory activity on the SnRK1 complex. Taken together, our results support a model in which DUF581-9 negatively regulates SnRK1 activity under energy sufficient conditions. Turnover over of the protein provides a rapid way for SnRK1 activation under energy deficit without the need of de-novo protein synthesis.

plant biology↗

bioRxiv2021

PEPc-mediated CO2 assimilation provides carbons to gluconeogenesis and the TCA cycle in both dark-exposed and illuminated guard cells

Evidence suggests that guard cells have higher rate of phosphoenolpyruvate carboxylase (PEPc)-mediated dark CO2 assimilation than mesophyll cells. However, it is unknown which metabolic pathways are activated following dark CO2 assimilation in guard cells. Furthermore, it remains unclear how the metabolic fluxes throughout the tricarboxylic acid (TCA) cycle and associated pathways are regulated in illuminated guard cells. Here we used 13C-HCO3 labelling of tobacco guard cells harvested under continuous dark or during the dark-to-light transition to elucidate principles of metabolic dynamics downstream of CO2 assimilation. Most metabolic changes were similar between dark-exposed and illuminated guard cells. However, illumination increased the 13C-enrichment in sugars and metabolites associated to the TCA cycle. Sucrose was labelled in the dark, but light exposure increased the 13C-labelling into this metabolite. Fumarate was strongly labelled under both dark and light conditions, while illumination increased the 13C-enrichment in pyruvate, succinate and glutamate. Only one 13C was incorporated into malate and citrate in either dark or light conditions. Our results collectively suggest that the PEPc-mediated CO2 assimilation provides carbons for gluconeogenesis, the TCA cycle and glutamate synthesis and that previously stored malate and citrate are used to underpin the specific metabolic requirements of illuminated guard cells. HighlightPEPc-mediated CO2 assimilation provides carbons for gluconeogenesis and the TCA cycle, whilst previously stored malate and citrate are used to underpin the specific metabolic requirements of illuminated guard cells.

plant biology↗

bioRxiv2018

Kingdom-wide comparison reveals conserved diurnal gene expression in Archaeplastida

Plants have adapted to the diurnal light-dark cycle by establishing elaborate transcriptional programs that coordinate innumerable metabolic, physiological, and developmental responses to the external environment. These transcriptional programs have been studied in only a few species, and their function and conservation across algae and plants is currently unknown. We performed a comparative transcriptome analysis of the diurnal cycle of nine members of Archaeplastida, and we observed that, despite large phylogenetic distances and dramatic differences in morphology and lifestyle, diurnal transcriptional programs of these organisms are similar. However, the establishment of multicellularity coincided with the uncoupling of cell division from the diurnal cycle and decreased diurnal control of the expression of the biological pathways. Hence, our study provides evidence for the universality of diurnal gene expression and elucidates its evolutionary history among different photosynthetic eukaryotes.

evolutionary biology↗

bioRxiv2018

Vascular brassinosteroid receptors confer drought resistance without penalizing plant growth

Drought represents a major threat to food security. Mechanistic data describing plant responses to drought have been studied extensively and genes conferring drought resistance have been introduced into crop plants. However, plants with enhanced drought resistance usually display lower growth, highlighting the need for strategies to uncouple drought resistance from growth. Here, we show that overexpression of BRL3, a vascular-enriched member of the brassinosteroid receptor family, can confer drought stress tolerance in Arabidopsis. Whereas loss-of-function mutations in the ubiquitously expressed BRI1 receptor leads to drought resistance at the expense of growth, overexpression of BRL3 receptor confers drought tolerance without penalizing overall growth. Systematic analyses reveal that upon drought stress, increased BRL3 triggers the accumulation of osmoprotectant metabolites including proline and sugars. Transcriptomic analysis suggests that this results from differential expression of genes in the vascular tissues. Altogether, this data suggests that manipulating BRL3 expression could be used to engineer drought tolerant crops.

plant biology↗

bioRxiv2017

Wide sampling of natural diversity identifies novel molecular signatures of C4 photosynthesis

Introductory paragraphMuch of biology is associated with convergent traits, and it is challenging to determine the extent to which underlying molecular mechanisms are shared across phylogeny. By analyzing plants representing eighteen independent origins of C4 photosynthesis, we quantified the extent to which this convergent trait utilises identical molecular mechanisms. We demonstrate that biochemical changes that characterise C4 species are recovered by this process, and expand the paradigm by four metabolic pathways not previously associated with C4 photosynthesis. Furthermore, we show that expression of many genes that distinguish C3 and C4 species respond to low CO2, providing molecular evidence that reduction in atmospheric CO2 was a driver for C4 evolution. Thus the origin and architecture of complex traits can be derived from transcriptome comparisons across natural diversity.

plant biology↗