Biology subjects

Solano, R.

Publications and source records attributed to Solano, R..

14 recordsLinked to original sources

bioRxiv2026

MpILR1 Hydrolyzes Jasmonate-Amino Acid Conjugates to Activate dn-iso-OPDA Signaling in Marchantia polymorpha.

Jasmonates are essential phytohormones that coordinate defense responses and developmental programs across land plants. In angiosperms, the active jasmonate ligand jasmonoyl-L-isoleucine (JA-Ile), is produced through GH3-mediated conjugation of jasmonic acid to isoleucine and JA-Ile homeostasis is further shaped by ILR1/ILL-family amidohydrolases. In contrast, the primary bioactive jasmonate ligand in bryophytes, dinor-12-oxo-phytodienoic acid (dn-iso-OPDA), is inactivated through conjugation with amino acids, raising the question of whether these conjugates constitute a reversible hormone reservoir or an irreversible catabolic end point. Although the ILR1-like family has been characterized extensively for its role in auxin and jasmonate homeostasis in angiosperms, its function in bryophytes remains basically unexplored. Here we show that MpILR1, the sole Marchantia ortholog of the ILR1/ILL family, hydrolyzes a specific subset of dn-iso-OPDA-amino acid conjugates in vivo. Loss-of-function Mpilr1 mutants exhibit enhanced accumulation of dn-iso-OPDA conjugated to hydrophobic amino acids (Val, Leu and Ile) but not to hydrophilic residues (His, Glu and Gln), demonstrating substrate-selective hydrolysis. MpILR1 hydrolytic activity is required for full dn-iso-OPDA-mediated responses, including transcriptional activation and defense against gastropod herbivory. These findings establish MpILR1 as a key positive regulator of jasmonate signaling in Marchantia polymorpha and suggest that hormone conjugation/deconjugation is an ancient regulatory mechanism evolved during plant terrestrialization.

plant biology↗

bioRxiv2025

MpNPR modulates lineage-specific oil body development and defence against gastropod herbivory in Marchantia polymorpha

The transition to land exposed early plants to novel biotic constraints, creating strong selection pressures that drove the evolution of the plant immune system. Extant land plants comprise two major groups, tracheophytes and bryophytes, which include liverworts, hornworts and mosses. These two groups diverged early after land colonization, and thus, immune mechanisms have also been subjected to independent evolution. Here, we investigated the function of the unique NPR in the liverwort Marchantia polymorpha and report that it exhibits a specialised immune function relative to its orthologs in tracheophytes. We show that MpNPR modulates the formation of oil bodies, a synapomorphy of liverworts, which function as storage organelles for secondary metabolites and defence against arthropods. We found that MpNPR interacts with MpERF13, a transcription factor controlling oil body differentiation, and that plants with altered levels of MpNPR are misregulated in the expression of MpERF13-dependent genes. Furthermore, we uncover that MpNPR and MpERF13 are required for the defence against snail herbivory. Finally, we show that the ability of MpNPR to induce oil body formation and resistance to gastropods is fully dependent on MpERF13. Taken together, our results demonstrate that NPR mediates a novel regulatory pathway in lineage-specific oil body formation and immunity against gastropod herbivory through the MpERF13 TF in Marchantia, while also pinpoint a novel specialised evolutionary trajectory of NPR in liverworts.

plant biology↗

bioRxiv2025

Peroxisome protein import deficiency causes heart failure in mouse and human

Peroxisomes are ubiquitous cellular organelles with potentially vital roles in lipid and reactive oxygen metabolism. The metabolic demands of the heart are substantial; however, the contribution of peroxisomes to cardiac development, health, and their role in heart failure (HF) remain largely unexplored. We developed and examined a mouse and an engineered human myocardium (EHM) model with a deficiency in cardiac peroxisome biogenesis to investigate the role of peroxisomes in cardiac function and pathology. In the EHM, loss of peroxisome protein import and subsequent peroxisomal metabolic impairment trigger mitochondrial damage and compromise cellular respiration and energy production. Peroxisome dysfunction results in incoherent electrical conduction, defective Ca2+-handling, and ultimately presentation of a HF phenotype with pathological force generation. These phenotypes are mirrored in an orthogonal murine model system with defective cardiac peroxisome biogenesis. Preload-dependent deficits in force generation due to insufficient energy supply are eventually fatal. Thus, peroxisomes play an important role in sustaining normal heart operations. Vice versa, peroxisome maintenance is compromised in pressure overload-induced HF, establishing peroxisomes as potential modulators of pathology and targets of therapy.

cell biology↗

bioRxiv2025

Trimodal Single-Cell Gene Regulatory Networks Reveal Principles of Stemness Loss and Cell Fate Acquisition in Human Hematopoiesis

Hematopoiesis requires the coordinated loss of stemness and acquisition of lineage identity, yet the regulatory logic and principles underlying these transitions has remained elusive. Single-cell studies suggest that hematopoietic stem and progenitor cells progress along continuous trajectories, but this view conflicts with the existence of discrete, functionally validated populations. Here, we establish the first dynamic, enhancer-based gene regulatory networks (eGRNs) that resolve the molecular programs underlying early human hematopoietic fate decisions. Built on a high-resolution trimodal framework generated with TEA-seq, these networks integrate simultaneously measured transcription factor abundance, enhancer and promoter accessibility, and gene expression within single-cell trajectories anchored to immunophenotypically defined populations. Our framework reveals that stemness loss and lineage acquisition are temporally and mechanistically uncoupled: stemness programs decline gradually through reduced TF abundance long before chromatin closure, whereas lineage identity emerges stepwise through enhancer reconfiguration and activation of lineage-defining eGRNs. This process generates discrete regulatory states that align with immunophenotypically defined populations. Together, these findings reconcile continuous and discrete models of hematopoiesis and establish eGRNs as a powerful framework for defining cell types by their regulatory logic. In addition, we provide an interactive web-based resource to facilitate further investigation of eGRNs and trajectories during early human hematopoiesis.

genomics↗

bioRxiv2024

Conjugation of dn-OPDA with amino acids inhibits its hormonal bioactivity in Marchantia polymorpha

Jasmonates are important phytohormones activating plant tolerance to biotic and abiotic stress, as well as different development processes. A conserved signalling pathway activated by distinct hormones in different plant species mediates these responses: dinor-12-oxo-phytodienoic acid (dn-OPDA) isomers in bryophytes and lycophytes, and JA-Ile in most vascular plants. The final responses depend, in many cases, on the accumulation of specialized metabolites. To identify novel compounds regulated by the dn-OPDA pathway in Marchantia, untargeted metabolomic analyses were carried out in response to dn-OPDA-regulated stress. A novel group of molecules were identified as dn-OPDA-amino acid conjugates (dn-OPDA-aas), and their accumulation after wounding and herbivory confirmed by targeted metabolic profiling in Marchantia and all species in which we previously found dn-iso-OPDA. Mutants in GRETCHEN-HAGEN 3A (MpGH3A) failed to accumulate dn-OPDA-aa conjugates, and showed a constitutive activation of the OPDA pathway and increased resistance to herbivory. Our results show that dn-iso-OPDA bioactivity is reduced by conjugation with amino acids. Therefore, a dichotomous role of jasmonate conjugation in land plants is highlighted: jasmonic acid (JA) conjugation with isoleucine (Ile) produce the bioactive JA-Ile in tracheophytes, whereas conjugation of dn-iso-OPDA with different amino acids disactivate the hormone in bryophytes and lycophytes.

plant biology↗

bioRxiv2023

Evolution of the jasmonate ligands and their biosynthetic pathways

Jasmonates are phytohormones that regulate multiple aspects of plant development and responses to stress, activating a conserved signaling pathway in land plants. The characterization of jasmonates biosynthetic and signaling pathways revealed that (+)-7-iso-JA-Ile (JA-Ile) is the ligand for the COI1/JAZ receptor in angiosperms, where jasmonates are synthesized through the OPR3-dependent or OPR3-independent pathways. More recently, studies on different model species identified dn-cis-OPDA, dn-iso-OPDA and {Delta}4-dn-iso-OPDA as the ligands of the COI1/JAZ receptor in the liverwort Marchantia polymorpha, and a receptor-independent role for several jasmonates in streptophytes. To understand the distribution of bioactive jasmonates in the green lineage and how their biosynthetic pathways evolved, we combined phylogenetic analyses and jasmonates metabolomics in representative species from different lineages. We found that both OPDA and dn-cis-OPDA are ubiquitous in land plants and present also in charophyte algae, underscoring their importance as ancestral signalling molecules. In contrast, JA-Ile biosynthesis emerged within lycophytes coincident with the evolutionary appearance of JAR1 function. We show that JA biosynthesis mediated by OPR1/OPR2 appeared in charophytes most likely as a degradation pathway of OPDA/dn-cis-OPDA before OPR3 emergence. Therefore, our results demonstrate that the OPR3-independent JA biosynthesis pathway is ancient and predates the evolutionary appearance of the OPR3-dependent pathway. Moreover, we identified a negative correlation between dn-iso-OPDA and JA-Ile in land plants which supports that dn-iso-OPDA is the relevant form of the hormone perceived by COI1/JAZ in bryophytes and lycophytes.

plant biology↗

bioRxiv2022

The transcriptional regulator JAZ8 interacts with the C2 protein from geminiviruses and limits the viral infection in Arabidopsis

Jasmonates (JAs) are phytohormones that finely regulate critical biological processes, including plant development and defense. JASMONATE ZIM-DOMAIN (JAZ) proteins are crucial keeping JA-responsive genes in a repressed state. In the presence of JA-Ile, JAZ repressors are ubiquitinated and targeted for degradation by the ubiquitin/proteasome system, allowing the activation of the downstream transcription factors and, consequently, the activation of JA-responsive genes. A growing body of evidence has shown that JA signalling is crucial in defending against plant viruses and their insect vectors. Here, we describe the interaction of C2 proteins from two geminiviruses from the genus Begomovirus, tomato yellow curl Sardinia virus (TYLCSaV) and tomato yellow leaf curl virus (TYLCV), with the transcriptional repressor JAZ8 from Arabidopsis thaliana and its closest orthologue in tomato, SlJAZ9. Both JAZ and C2 proteins colocalize in the nucleus, forming discrete nuclear speckles. Overexpression of JAZ8 did not lead to altered responses to TYLCV infection; however, knock-down of JAZ8 favours the geminiviral infection in plants. Low levels of JAZ8 likely affect the viral infection specifically since JAZ8-silenced plants do not display developmental phenotypes nor present differences in their interaction with the viral insect vector. Our results show that JAZ8 interacts with geminiviral C2 proteins and exerts an anti-geminiviral effect.

plant biology↗

bioRxiv2021

An evolutionarily ancient Fatty Acid Desaturase is required for the synthesis of hexadecatrienoic acid, which is the main source of the bioactive jasmonate in Marchantia polymorpha

Jasmonates are fatty acid derived hormones that regulate multiple aspects of plant development, growth and stress responses. Bioactive jasmonates, defined as the ligands of the conserved COI1 receptor, differ between vascular plants and bryophytes (using jasmonoyl-L-isoleucine; JA-Ile and dinor-12-oxo-10,15(Z)-phytodienoic acid; dn-OPDA, respectively). Whilst the biosynthetic pathways of JA-Ile in the model vascular plant Arabidopsis thaliana have been elucidated, the details of dn-OPDA biosynthesis in bryophytes are still unclear. Here, we identify an ortholog of Arabidopsis Fatty Acid Desaturase 5 (AtFAD5) in the model liverwort Marchantia polymorpha and show that FAD5 function is ancient and conserved between species separated by more than 450 million years of independent evolution. Similar to AtFAD5, MpFAD5 is required for the synthesis of 7Z-hexadecenoic acid. Consequently, in Mpfad5 mutants the hexadecanoid pathway is blocked, dn-OPDA levels almost completely depleted and normal chloroplast development is impaired. Our results demonstrate that the main source of dn-OPDA in Marchantia is the hexadecanoid pathway and the contribution of the octadecanoid pathway, i.e. from OPDA, is minimal. Remarkably, despite extremely low levels of dn-OPDA, MpCOI1-mediated responses to wounding and insect feeding can still be activated in Mpfad5, suggesting that dn-OPDA is not the only bioactive jasmonate and COI1 ligand in Marchantia.

plant biology↗

bioRxiv2021

Conserved secreted effectors determine endophytic growth and multi-host plant compatibility in a vascular wilt fungus

Fungal interactions with plant roots, either beneficial or detrimental, have a major impact on agriculture and ecosystems. The soil inhabiting ascomycete Fusarium oxysporum (Fo) constitutes a species complex of worldwide distribution causing vascular wilt in more than a hundred different crops. Individual isolates of the fungus exhibit host-specific pathogenicity, determined by proteinaceous effectors termed secreted in xylem (SIX). However, such isolates can also colonize roots of non-host plants asymptomatically as endophytes, or even protect them against pathogenic isolates. The molecular determinants of multi-host plant colonization are currently unknown. Here, we identified a set of fungal effectors termed ERCs (Early Root Compatibility effectors), which are secreted during early biotrophic growth of Fo on both host and non-host plants. In contrast to the strain-specific SIX effectors, which are encoded on accessory genomic regions, ERCs are encoded on core regions and are found across the entire Fo species complex as well as in other phytopathogens, suggesting a conserved role in fungus-plant associations. Targeted deletion of ERC genes in a pathogenic Fo isolate resulted in reduced virulence on the host plant and rapid activation of plant immune responses, while in a non-pathogenic isolate it led to impaired root colonization and loss of biocontrol ability. Strikingly, some ERCs also contribute to Fo infection on the non-vascular land plant Marchantia polymorpha. Our results reveal an evolutionarily conserved mechanism for multi-host colonization by root infecting fungi.

plant biology↗

bioRxiv2021

SARS-CoV-2 fears green: the chlorophyll catabolite Pheophorbide a is a potent antiviral

SARS-CoV-2 pandemic is having devastating consequences worldwide. Although vaccination advances at good pace, effectiveness against emerging variants is unpredictable. The virus has displayed a remarkable resistance to treatments and no drugs have been proved fully effective against Covid-19. Thus, despite the international efforts, there is still an urgent need for new potent and safe antivirals against SARS-CoV-2. Here we exploited the enormous potential of plant metabolism using the bryophyte Marchantia polymorpha and identified a potent SARS-CoV-2 antiviral, following a bioactivity-guided fractionation and mass-spectrometry approach. We found that the chlorophyll derivative Pheophorbide a (PheoA), a porphyrin compound similar to animal Protoporphyrin IX, has an extraordinary antiviral activity against SARS-CoV-2 preventing infection of cultured monkey and human cells, without noticeable cytotoxicity. We also show that PheoA prevents coronavirus entry into the cells by directly targeting the viral particle. Besides SARS-CoV-2, PheoA also displayed a broad-spectrum antiviral activity against (+) strand RNA viral pathogens such as HCV, West Nile, and other coronaviruses, but not against (-) strand RNA viruses, such as VSV. Our results indicate that PheoA displays a remarkable potency and a satisfactory therapeutic index, which together with its previous use in photoactivable cancer therapy in humans, suggest that it may be considered as a potential candidate for antiviral therapy against SARS-CoV-2.

molecular biology↗

bioRxiv2021

Marchantia polymorpha model reveals conserved infection mechanisms in the vascular wilt fungal pathogen Fusarium oxysporum

The non-vascular plant Marchantia polymorpha has emerged as a valuable model for studying evolutionarily conserved microbial infection strategies and plant immune responses. However, only a handful of fungal pathogens of Marchantia have been described so far. Here we establish a new pathosystem using the root-infecting vascular wilt fungus Fusarium oxysporum. On angiosperms, this fungus exhibits exquisite adaptation to the plant vascular niche and host-specific pathogenicity, both of which are conferred by lineage-specific effectors secreted during growth in the xylem. We show that F. oxysporum isolates with different lifestyles - pathogenic or endophytic - are able to infect this non-vascular liverwort causing tissue maceration and plant cell killing. Similar to bacterial pathogens, F. oxysporum induces a PAMP-triggered immune response in M. polymorpha. Analysis of isogenic fungal mutants established that infection of Marchantia requires conserved fungal pathogenicity mechanisms such as mitogen activated protein kinases, transcriptional regulators and cell wall remodeling enzymes. Remarkably, lineage-specific virulence effectors are dispensable for infection, most likely due to the absence of xylem tissue in this non-vascular plant. The F. oxysporum - M. polymorpha system provides new insights into the mechanism and evolution of pathogenic and endophytic fungus-plant interactions. Significance statementRoot-infecting vascular fungi cause wilt diseases and provoke devastating losses in hundreds of crops. It is currently unknown how these pathogens evolved and whether they infect non-vascular plants, which diverged from vascular plants over 450 million years ago. Here we show that two strains of the fungus Fusarium oxysporum with opposed lifestyles, causing either wilting and death or beneficial protection on tomato, produce similar disease symptoms on the non-vascular plant Marchantia polymorpha. We define a set of core fungal pathogenicity factors required on both vascular and non-vascular plants and show that host-specific effectors contributing to disease on tomato are dispensable on Marchantia. These findings suggest that systemic wilt disease evolved in fungal pathogens after the emergence of vascular land plants.

plant biology↗

bioRxiv2021

Chemical screen identifies a small molecule antagonizing JA-Ile perception and auxin responses.

The phytohormone JA-Ile regulates many stress responses and developmental processes in plants. A co-receptor complex formed by the F-box protein COI1 (Coronatine Insensitive 1) and a JAZ (Jasmonate ZIM-domain) repressor perceives the hormone. JA-Ile antagonists are invaluable tools for exploring the role of JA-Ile in specific tissues and developmental stages, and for identifying regulatory processes of the signalling pathway. Using two complementary chemical screens, we identified three compounds that exhibit a robust inhibitory effect on both the hormone-mediated COI-JAZ interaction and degradation of JAZ1 and JAZ9 in vivo. One molecule, J4, also restrains specific JA-induced physiological responses in different angiosperm plants, including JA-mediated gene expression, growth inhibition, chlorophyll degradation and anthocyanin accumulation. Interaction experiments with purified proteins indicate that J4 directly interferes with the formation of the Arabidopsis (Arabidopsis thaliana) COI1-JAZ complex otherwise induced by JA. The antagonistic effect of J4 on COI1- JAZ also occurs in the liverwort Marchantia polymorpha, suggesting the mode of action is conserved in land plants. Besides JA signalling, J4 works as an antagonist of the closely-related auxin signalling pathway, preventing TIR1/Aux-IAA interaction and auxin responses in planta, including hormone-mediated degradation of an auxin repressor, gene expression and gravitropic response. However, J4 does not affect other hormonal pathways. Altogether, our results show that this dual antagonist competes with JA-Ile and auxin, preventing the formation of phylogenetically related receptor complexes. J4 may be a useful tool to dissect both the JA-Ile and auxin pathways in particular tissues and developmental stages since it reversibly inhibits these pathways. One sentence summaryA chemical screen identified a molecule that antagonizes jasmonate perception by directly interfering with receptor complex formation in phylogenetically distant vascular and non-vascular plants.

plant biology↗

bioRxiv2019

Integrated Multi-omic Framework of the Plant Response to Jasmonic Acid

Understanding the systems-level actions of transcriptional responses to hormones provides insight into how the genome is reprogrammed in response to environmental stimuli. Here, we investigate the signaling pathway of the hormone jasmonic acid (JA), which controls a plethora of critically important processes in plants and is orchestrated by the transcription factor MYC2 and its closest relatives in Arabidopsis thaliana. We generated an integrated framework of the response to JA that spans from the activity of master and secondary-regulatory transcription factors, through gene expression outputs and alternative splicing to protein abundance changes, protein phosphorylation and chromatin remodeling. We integrated time series transcriptome analysis with (phospho)proteomic data to reconstruct gene regulatory network models. These enable us to predict previously unknown points of crosstalk from JA to other signaling pathways and to identify new components of the JA regulatory mechanism, which we validated through targeted mutant analysis. These results provide a comprehensive understanding of how a plant hormone remodels cellular functions and plant behavior, the general principles of which provide a framework for analysis of cross-regulation between other hormone and stress signaling pathways.

plant biology↗

bioRxiv2018

PIF transcription factors link a neighbor threat cue to accelerated reproduction in Arabidopsis

Changes in light quality indicative of competition for this essential resource influence plant growth and developmental transitions. Little is known about neighbor proximity-induced acceleration of reproduction. phytochrome B (phyB) senses light cues from plant competitors ultimately leading to the expression of the floral inducers FLOWERING LOCUS (FT) and TWIN SISTER of FT (TSF). Here we show that three PHYTOCHROME INTERACTING FACTOR (PIF) transcriptional regulators act directly downstream of phyB to promote expression of FT and TSF. Neighbor proximity enhances PIF accumulation towards the end of the day coinciding with enhanced floral inducer expression. We present evidence for direct PIF-mediated TSF expression. The relevance of our findings is illustrated by the prior identification of FT, TSF and PIF4 as loci underlying flowering time regulation in nature.\n\nOne Sentence SummaryPIF transcription factors mediate reproductive transition in response to neighbor proximity light cues in Arabidopsis.

plant biology↗