Biology subjects

Rodriguez, M. S.

Publications and source records attributed to Rodriguez, M. S..

6 recordsLinked to original sources

bioRxiv2026

Transient uncoupling of the Suc-Tre6P-SnRK1 nexus during salt stress associates with biphasic metabolic reprogramming and root plasticity

Soil salinization threatens global agriculture reducing yields, yet the metabolic signals controlling salt-sensitive root plasticity in alfalfa remain unclear. We hypothesize that salinity transiently uncouples the sucrose-trehalose-6-P (Tre6P)- Sucrose non-fermenting kinase 1 (SnRK1) nexus, aligning with a biphasic root metabolic response and altered root architecture. Alfalfa seedlings were grown in a hydroponic system and exposed to 200 mM NaCl, with root samples collected from 1 h to 7 d. While primary root growth and biomass remained unchanged, lateral root development was enhanced under salinity. Early response (1 h-1 d) was characterized by reduced carbon metabolites, low Tre6P, increased malondialdehyde, and SnRK1 activation, with a decline in glycolytic and TCA intermediates. During this phase, sucrose was negatively correlated with both Tre6P and SnRK1. Late response (3-7 d) showed a SnRK1 reactivation, Tre6P recovery, and osmoprotectant accumulation, including increased antioxidant capacity (+75% at 3dpt), proline (+178%), and sucrose (+18%) and starch depletion (-57%) at 7dpt respect to control. These metabolic changes coincided with the enhanced lateral root emergence. These findings indicate a two-phase response: early metabolic downscaling with transient Suc-Tre6P-SnRK1 disruption, followed by recovery with Tre6P restoration, SnRK1 reactivation, osmoprotection, and sustained root plasticity under salinity. HighlightSalinity triggers a temporary metabolic shift in alfalfa roots: plants first conserve energy, then adapt to stress, maintaining lateral root growth and flexible root architecture.

plant biology↗

bioRxiv2025

Wave-like SnRK1 Activation and Tre6P-Sucrose Imbalance Shape Early Salt Stress Response in Growing Alfalfa Leaves

Alfalfa (Medicago sativa L.) is a key forage crop valued for its adaptability and nutritional quality, yet salinity significantly limits its productivity, particularly in arid regions. Understanding early stress responses is crucial for improving resilience. Salt stress impairs leaf growth and photosynthesis, triggering complex, time-dependent signaling. Sucrose non-fermenting kinase 1 (SnRK1), a central metabolic sensor, regulates metabolism and growth under stress. We investigated the dynamics of SnRK1, sucrose, and trehalose-6- phosphate (Tre6P) during leaf expansion in a salt-tolerant alfalfa cultivar. Plants were hydroponically grown and exposed to 200 mM NaCl. Stress induced transient declines in chloroplast performance (Fv/Fm, performance index). SnRK1 activity peaked within 1 hour post-treatment (hpt), likely initiating metabolic shifts. By 3 hpt, sugar metabolism shifted, with increased catabolism, TCA cycle modulation, and glucose-6-phosphate accumulation. SnRK1 and sucrose showed opposing wave-like patterns, with sucrose peaking at 1 day post-treatment (dpt) as Tre6P declined, indicating a disrupted regulatory link. A second SnRK1 peak at 3 dpt correlated with reduced leaf growth. Exogenous sucrose inhibited SnRK1, while NaCl enhanced it. This is the first report of wave-like SnRK1 activation and Tre6P-sucrose uncoupling in alfalfa, highlighting early SnRK1 activation as key to salt stress adaptation. HighlightsO_LIEarly SnRK1 activation is a key determinant of salt stress response in alfalfa, linking early biochemical shifts to downstream metabolic alteration. C_LIO_LIFirst evidence of a wave-like SnRK1 activation pattern and disruption of the Tre6P- Sucrose nexus reveals novel dynamics in alfalfas stress signaling. C_LIO_LISucrose inhibits SnRK1 activity in source leaves with or without NaCl C_LI

plant biology↗

bioRxiv2021

LGG-1/GABARAP lipidation is dispensable for autophagy and development in C .elegans

The ubiquitin-like proteins Atg8/LC3/GABARAP are required for multiple steps of autophagy such as initiation, cargo recognition and engulfment, vesicle closure and degradation. Most of LC3/GABARAP functions are considered dependent on their post-translational modifications and addressing to membranes through a conjugation to a lipid, the phosphatidylethanolamine. Contrarily to mammals, C. elegans possesses single homologs of LC3 and GABARAP families, named LGG-2 and LGG-1. Using site directed mutagenesis, we inhibited the conjugation of LGG-1 to the autophagosomal membrane and generated mutants that express only cytosolic forms, either the precursor or the cleaved protein. LGG-1 is an essential gene for autophagy and development in C. elegans, but we discovered that its functions could be fully achieved independently of its localization to the membrane. This study reveals an essential role for the cleaved form of LGG-1 in autophagy but also in an autophagy independent embryonic function. Our data question the use of the lipidated GABARAP/LC3 as the main marker of autophagic flux and highlight the high plasticity of autophagy.

cell biology↗

bioRxiv2021

The water-soluble chitosan derivative, N-methylene phosphonic chitosan, is an effective fungicide against the phytopathogen Fusarium eumartii

Chitosan has been considered an environmental-friendly polymer. However, its use in agriculture has not been extended yet due to its relatively low solubility in water. In an attempt to improve such chemical characteristics, a chitosan-derivative prepared by adding a phosphonic group to chitosan N-methylene phosphonic chitosan, NMPC, was obtained from shrimp fishing industry waste from Argentinean Patagonia. This study showed that NMPC had a fungicidal effect on the phytopathogenic fungus Fusarium solani f. sp. eumartii (F. eumartii). NMPC inhibited F. eumartti mycelial growth and spore germination with low IC50 values. In vivo studies showed that NMPC affected fungal membrane permeability, ROS production, and cell death. NMPC also exerted antifungal effects against two other phytopathogens, Botrytis cinerea, and Phytophthora infestans. NMPC did not affect tomato cell viability at the same doses applied to these phytopathogens. Furthermore, the selective cytotoxicity of NMPC could give it added value in its application as an antimicrobial agent in agriculture.

microbiology↗

bioRxiv2021

Biological, Molecular And Phiysiological Characterization Of Four Soybean mosaic virus Isolates Present In Argentine Soybean Crops

Soybean mosaic virus (SMV) causes systemic infections in soybean plants, leading to chlorotic mosaic and producing significant yield losses. The virus is widely distributed in all soybean production areas in the world. In Argentina, three geographical isolates were identified: Marcos Juarez (MJ), Manfredi (M), and North Western Argentina (NOA), and another isolate named "Planta Vinosa" (PV), which causes severe necrosis symptoms in some cultivars. Here, the biological, molecular and physiological characterization of these isolates was performed for the first time. Three of the four isolates showed a low genetic divergence in the evaluated genes (P1, CI and CP). Although SMV-NOA and SMV-PV had high homology at the sequence level, they showed wide differences in pathogenicity, seed mottling and the ability of transmission by seeds or aphids, as well as in physiological effects. SMV-NOA caused early alterations (before symptom appearance, BS) in {Phi}PSII and MDA content in leaves with respect to the other isolates. After the appearance of macroscopic symptoms (late symptoms, LS), SMV-M caused a significant increase in the content of MDA, total soluble sugars, and starch with respect to the other isolates. Thus, early alterations of {Phi}PSII and soluble sugars might have an impact on late viral symptoms. Likewise, SMV-MJ developed more severe symptoms in the susceptible Davis cultivar than in DM 4800. Therefore, our results show differences in genome, biological properties and physiological effects among SMV isolates as well as different interactions of SMV-MJ with two soybean cultivars.

plant biology↗

bioRxiv2020

Cassava common mosaic virus causes photosynthetic alterations associated with changes in chloroplast ultrastructure and carbohydrate metabolism of cassava plants

Cassava common mosaic virus (CsCMV) is a potexvirus that causes systemic infections in cassava plants, leading to chlorotic mosaic and producing significant yield losses. To date, the physiological alterations and the mechanism underlying biotic stress during the cassava-CsCMV compatible interaction remains unknown. In this study, we found that CsCMV infection adversely modified chloroplast structure and had functional effects on chloroplasts in source leaves during the course of viral infection. Extrusion of the chloroplast membrane with amoeboid-shaped appearance was observed in infected mesophyll cells. These alterations were associated with lower relative chlorophyll content, and reduced PSII efficiency and CO2 fixation. Moreover, an oxidative stress process was observed in CsCMV-infected plants. Strong declines in the maximum quantum yield of primary photochemistry (Fv/Fm) were observed in infected plants. Furthermore, the analysis of Chlorophyll-a fluorescence (ChlF) evidenced a progressive loss of both oxygen evolving complex activity and "connectivity" within the tripartite system (core antenna-LHCII-Reaction Centre). Other effects of the pathogen included reduction of starch and maltose content in source leaves, and a significant increase of the sucrose/starch ratio, which indicates alteration pattern of carbon. Our results suggest that CsCMV induces chloroplast distortion associated with progressive chloroplast function loss and diversion of carbon flux in source leaf tissue, which should be key in inducing yield losses of infected crops. Main conclusionCsCMV infection adversely modified chloroplast structure and had functional effects on chloroplasts during the course of viral infection, associated with metabolic adjustment in cassava source leaves, which would partly explain cassava root yield losses.

plant biology↗