Biology subjects

Margarit, E.

Publications and source records attributed to Margarit, E..

3 recordsLinked to original sources

bioRxiv2024

Drought resistance and improved yield result from modified malate metabolism in guard and vascular companion cells

Drought is a major threat to food security. Water loss through stomata is an inevitable consequence of CO2 uptake, and water deficit inhibits plant growth, making it challenging to develop drought-resistant strategies without compromising yield. Here, we generated tobacco plants expressing a maize NADP-dependent malate decarboxylating enzyme in stomata and vascular cells (ME plants), which show higher seed yield and faster maturation compared to wild-type (WT) plants under normal irrigation and after drought. While WT plants die after 45 days of drought, ME plants survive without any adverse effects on seed production. In addition, ME plants exhibit improved photosynthetic efficiency despite reduced stomatal conductance and changes in stem morphology, which are likely related to their ability to withstand drought. We propose that enhanced C4-like biochemistry in cells surrounding the vascular system and increased sugar export likely compensated for the reduced stomatal conductance in ME plants. The study demonstrates that cell-targeted metabolic modifications can avoid pleiotropic effects and facilitate the stacking of beneficial traits to improve crop design. Significance StatementDrought is one of the biggest threats to global food security, and its impact on crop yield is expected to worsen due to climate change. Traditionally, drought resistance has often come at the expense of yield, creating a negative trade-off. However, we present here a promising solution to this challenge. We have developed a novel approach that successfully uncouples the negative balance between drought resistance and yield. By introducing a maize enzyme into specific tobacco cells, we have created drought-resistant plants with faster growth and higher seed yield. Most importantly, after prolonged drought, while the wild type dies, the modified plants maintain their high yield. This technology paves the way for greater food security and resilience to climate change.

plant biology↗

bioRxiv2022

Genetic variations in G-Quadruplex forming sequences affect the transcription of human disease-related genes

Guanine-rich DNA strands can fold into non-canonical four-stranded secondary structures named G-quadruplexes (G4s). G4s folded in proximal promoter regions (PPR) are associated either with positive or negative transcriptional regulation. Given that single nucleotide variants (SNVs) affecting G4 folding (G4-Vars) may alter gene transcription, and that SNVs are associated with the human diseases onset, we undertook a comprehensive study of the G4-Vars genome-wide (G4-variome) to find disease-associated G4-Vars located into PPRs. We developed a bioinformatics strategy to find disease-related SNVs located into PPRs simultaneously overlapping with putative G4-forming sequences (PQSs). We studied five G4-Vars disturbing in vitro the folding and stability of the G4s located into PPRs, which had been formerly associated with sporadic Alzheimers disease (GRIN2B), a severe familiar coagulopathy (F7), atopic dermatitis (CSF2), myocardial infarction (SIRT1), and deafness (LHFPL5). Results obtained in cellulo for GRIN2B and F7 suggest that the G4 disruption due to the identified G4-Vars affect the transcription and are responsible for the mentioned diseases. Collectively, data suggest that G4-Vars may account for the different susceptibilities to human genetic diseases onset, and could be novel targets for diagnosis and drug design in precision medicine.

molecular biology↗

bioRxiv2021

Understanding C4 photosynthesis in Setaria by a proteomic and kinetic approach

Plants performing C4 photosynthesis have a higher productivity per crop area related to an optimized use of water and nutrients. This is achieved through a series of anatomical and biochemical features that allow the concentration of CO2 around RuBisCO. In C4 plants the photosynthetic reactions are distributed between two cell types, they initially fix the carbon to C4 acids within the mesophyll cells (M) and then transport these compounds to the bundle sheath cells (BS), where they are decarboxylated so that the resulting CO2 is incorporated into the Calvin cycle (CC). This work is focused on the comparative analysis of the proteins present in M and BS of Setaria viridis, a C4 model close relative of several major feed, fuel, and bioenergy grasses. The integration of kinetic and proteomic approaches agrees that the C4 compound malate is mainly decarboxylated in the chloroplasts of BS cells by NADP-malic enzyme (NADP-ME). Besides, NAD-malic enzyme (NAD-ME) located in the mitochondria could also contribute to the C4 carbon shuttle. We presented evidence of metabolic strategies that involve chloroplastic, mitochondrial and peroxisomal proteins to avoid the leakage of C4 intermediates in order to sustain an efficient photosynthetic performance. HighlightProteomic and kinetic analyses show metabolic strategies involving chloroplastic, mitochondrial and peroxisomal proteins to maintain the C4 cycle performance in parallel to other metabolic pathways.

plant biology↗