Biology subjects

Torregrosa, L.

Publications and source records attributed to Torregrosa, L..

4 recordsLinked to original sources

bioRxiv2024

Time-resolved transcriptomic of single V. vinifera fruits: membrane transports as switches of the double sigmoidal growth

By revealing that the grape berry loses one H+ per accumulated sucrose at the inception of ripening, adopting a single fruit paradigm elucidates the fundamentals of the malate-sugar nexus, previously obscured by asynchrony in population-based models of ripening. More broadly, the development of the individual fruit was revisited from scratch to capture the simultaneous changes in gene expression and metabolic fluxes in a kinetically relevant way from flowering to overripening. Dynamics in water, tartrate, malate, hexoses, and K+ fluxes obtained by combining individual single fruit growth and concentration data allowed to define eleven sub-phases in fruit development, which distributed on a rigorous curve in RNAseq PCA. WGCNA achieved unprecedented time resolutions in exploring transcript level-metabolic rate associations. A comprehensive set of membrane transporters was found specifically expressed during the first growth phase related to vacuolar over-acidification. Unlike in slightly more acidic citrus, H+ V-PPase transcripts were predominantly expressed, followed by V-ATPase and PH5, clarifying the thermodynamic limit beyond which replacement by the PH1/PH5 complex turns compulsory. Puzzlingly, bona fide ALMT kept a low profile at this stage, possibly replaced by a predominating uncharacterized anion channel. Then, the switch role of HT6 in sugar accumulation was confirmed, electroneutralized by malate vacuolar leakage and H+ pumps activation. HighlightsTo alleviate asynchronicity biases, transcripts showing strict coincidental timing with pericarp physiological phases were disentangled on single berries, enlightening the tight multifaceted membrane developmental control of sugar and acid fluxes.

plant biology↗

bioRxiv2024

The single-berry metabolomic clock paradigm reveals new stages and metabolic switches during grapevine berry development

O_LIAsynchronous development of berries causes metabolic chimerism in usual samples. We thus revisited the developmental changes in the metabolome of the Vitis vinifera single berries from anthesis to over-ripening. C_LIO_LIA dataset of 9,256 ions obtained by non-targeted ultra-performance liquid chromatography coupled to high-resolution mass spectrometry was submitted to an analysis workflow combining classification and dimension reduction tools, to reveal the dynamics of metabolite composition without phenological a priori. C_LIO_LIThis approach led to a metabolome-based definition of developmental stages, as well as the clustering of metabolites into 12 specific kinetic patterns. The single berry intrinsic metabolomic clock alleviates constitutive asynchronicity biases in the usual combination of phenological scales and observer clock. Such increase in temporal resolution enabled the identification of metabolite clusters annunciative of the onset of ripening since the herbaceous plateau. In particular, these clusters included transient lipidic changes and the start of ABA accumulation. We also highlighted a cluster of stilbenes that accumulate after sugar loading stops, during fruit shriveling. C_LIO_LIThis non-targeted approach enables a more precise and unbiased characterization of grapevine berry development through the metabolomic clock paradigm. The discovery of new metabolic milestones of berry development paves the way towards an unbiased assessment of berry physiological stages. C_LI

plant biology↗

bioRxiv2021

Evolving a new efficient mode of fructose utilization for improved bioproduction in Corynebacterium glutamicum

Fructose utilization in Corynebacterium glutamicum starts with its uptake and concomitant phosphorylation via the phosphotransferase system (PTS) to yield intracellular fructose 1-phosphate, which enters glycolysis upon ATP dependent phosphorylation to fructose 1,6-bisphosphate by 1-phosphofructokinase. This is known to result in a significantly reduced oxidative pentose phosphate pathway (oxPPP) flux on fructose (~10 %) compared to glucose (~60 %). Consequently, the biosynthesis of NADPH demanding products, e.g. L-lysine, by C. glutamicum is largely decreased, when fructose is the only carbon source. Previous works reported that fructose is partially utilized via the glucose specific PTS presumably generating fructose 6-phosphate. This closer proximity to the entry point of the oxPPP might increase oxPPP flux and consequently NADPH availability. Here, we generated deletion strains either lacking in the fructose-specific PTS or 1-phosphofructokinase activity. We used these strains in short-term evolution experiments on fructose minimal medium and isolated mutant strains, which regained the ability of fast growth on fructose as a sole carbon source. In these fructose mutants, the deletion of the glucose specific PTS, as well as the 6-phosphofructokinase gene, abolished growth, unequivocally showing fructose phosphorylation via glucose specific PTS to fructose 6-phosphate. Gene sequencing revealed three independent amino acid substitutions in PtsG (M260V, M260T, P318S). These three PtsG variants mediated faster fructose uptake and utilization compared to native PtsG. In-depth analysis of the effects of fructose utilization via these PtsG variants revealed significantly increased biomass formation, reduced side-product accumulation, and increased L-lysine production by 50 %.

synthetic biology↗

bioRxiv2021

Transcripts repressed at the stop of phloem unloading highlight the energy efficiency of sugar import in the ripening V. vinifera fruit.

Transcriptomic changes at the cessation of sugar accumulation in the pericarp of Vitis vinifera were addressed on single berries re-synchronized according to their individual growth patterns. The net rates of water, sugars and K+ accumulation inferred from individual growth and solute concentration confirmed that these inflows stopped simultaneously in the ripe berry, while the small amount of malic acid remaining at this stage was still being oxidized at low rate. Re-synchronized individual berries displayed negligible variations in gene expression among triplicates. RNA-Seq studies revealed sharp reprogramming of cell wall enzymes and structural proteins at the stop of phloem unloading, associated with an 80% repression of multiple sugar transporters and aquaporins on the plasma or tonoplast membranes, with the noticeable exception of H+/sugar symporters, that were rather weakly and constitutively expressed. This was verified in three genotypes placed in contrasted thermo-hydric conditions. The prevalence of SWEET suggests that electrogenic transporters would play a minor role on the plasma membranes of SE/CC complex and the one of the flesh, while sucrose/H+ exchangers dominate on its tonoplast. Cis-regulatory elements present in their promoters allowed to sort these transporters in different groups, also including specific TIPs and PIPs paralogs, and cohorts of cell wall related genes. Together with simple thermodynamic considerations, these results lead to propose that H+/sugar exchangers at the tonoplast, associated with a considerably acidic vacuolar pH, may exhaust cytosolic sugars in the flesh and alleviate the need for supplementary energization of sugar transport at the plasma membrane.

plant biology↗