Biology subjects

Fiol, D. F.

Publications and source records attributed to Fiol, D. F..

5 recordsLinked to original sources

bioRxiv2026

The DC1 domain protein Vacuoleless Gametophytes positively regulates salt stress tolerance in Arabidopsis thaliana

Vacuoleless Gametophytes (VLG) is a DC1 domain-containing protein initially characterized as essential for the development of both female and male gametophytes in Arabidopsis thaliana. In addition, VLG regulates stamen development through the involvement in lignin and jasmonic acid biosynthesis pathways. In this work, we report that VLG is also involved in salt stress tolerance in A. thaliana. Under salt stress, VLG-knock-down plants exhibited reduced germination, root elongation, biomass accumulation, photosynthetic pigment content, along with diminished expression of key salt-responsive genes. Conversely, these plants accumulated higher anthocyanins, and reactive oxygen species (H2O2 and O2-) compared to wilt type, indicating impaired oxidative stress control. In contrast, VLG-overexpressing plants showed a salt stress resistant phenotype with enhanced biomass and increased expression of salt-responsive genes under saline conditions. Together, these findings uncover an unexpected role for VLG as a positive regulator of salt tolerance, expanding the functional scope of DC1 domain proteins beyond reproductive development and providing new insights into plant mechanisms of abiotic stress resilience.

plant biology↗

bioRxiv2026

Nitric Oxide Modulates Auxin Signaling through TIR1 S-Nitrosylation During Thermomorphogenesis in Arabidopsis

Auxin, a central hormone coordinating plant growth, integrates both environmental and developmental signals to regulate cell expansion, division, and organ patterning. Among these environmental cues, elevated ambient temperatures trigger a suite of developmental adaptations collectively known as thermomorphogenesis. In this study, we identify nitric oxide (NO) as a key mediator in the temperature-dependent regulation of auxin signaling. Our results show that warm temperatures (28-29 {degrees}C) enhance auxin-induced NO accumulation in Arabidopsis thaliana seedlings. Using pharmacological and genetic approaches, we demonstrate that NO is required for proper thermomorphogenic responses in aerial tissues. This redox signal promotes the stabilization and nuclear localization of the F-box auxin receptor TIR1, a crucial step for the activation of downstream auxin responses. Specifically, tir1-1 seedlings expressing a non-nitrosylatable TIR1 variant mutated at the Cys140 residue exhibit impaired hypocotyl elongation and hyponasty under warm conditions compared to seedlings complemented with wild-type TIR1. These results highlight the functional relevance of the TIR1 Cys140 residue, a known target for S-nitrosylation, in coordinating thermomorphogenic responses. In contrast, the absence of TIR1 S-nitrosylation restricts primary root elongation at 22 {degrees}C but does not affect the growth-promoting effects of warm temperatures. Our findings uncover a novel redox-dependent regulatory layer in auxin signaling, where S-nitrosylation of TIR1 may modulate its stability and subcellular localization in a temperature- and organ-specific manner. This mechanism allows differential growth responses between shoot and root organs and highlights the complexity of hormonal and redox interplay during plant adaptation to elevated temperatures.

plant biology↗

bioRxiv2025

What Large Language Models Know About Plant Molecular Biology

Large language models (LLMs) are rapidly permeating scientific research, yet their capabilities in plant molecular biology remain largely uncharacterized. Here, we present MOBIPLANT, the first comprehensive benchmark for evaluating LLMs in this domain, developed by a consortium of 112 plant scientists across 19 countries. MOBIPLANT comprises 565 expert-curated multiple-choice questions and 1,075 synthetically generated questions, spanning core topics from gene regulation to plant-environment interactions. We benchmarked seven leading chat-based LLMs using both automated scoring and human evaluation of open-ended answers. Models performed well on multiple-choice tasks (exceeding 75% accuracy), although most of them exhibited a consistent bias towards option A. In contrast, expert reviews exposed persistent limitations, including factual misalignment, hallucinations, and low self-awareness. Critically, we found that model performance strongly correlated with the citation frequency of source literature, suggesting that LLM knowledge inherits the visibility distribution of the underlying scientific corpus. Consequently, models tend to be more reliable on consolidated topics and less reliable on under-cited or recently emerging ones. We also benchmarked agents equipped with web-search and additional tools in more complex tasks involving DNA sequence analysis. These agents were outperformed by domain specific models in sequence classification and regression tasks, indicating an opportunity for joint agentic systems that combine both the reasoning power of LLMs and the dedicated processing of DNA models. This understanding is key to guiding both the development of next-generation models and the informed use of current tools in the everyday work of plant researchers. MOBIPLANT is publicly available online in this link.

plant biology↗

bioRxiv2024

The DC1 domain protein Vacuoleless Gametophytes regulates stamen development in Arabidopsis

Vacuoleless Gametophytes (VLG) is a DC1 domain protein that was initially characterized as essential for early female and male gametophytes development in Arabidopsis. However, VLG expression was also detected in stamens, pistils and other sporophytic tissues, implying a broader role for this protein. As homozygous insertional VLG lines resulted unviable, we generated Arabidopsis amiRNA VLG knock-down plants to study the role of VLG in sporophyte development. The phenotypic characterization of VLG knock-down plants showed reduced seed set and indehiscent anthers with shorter filaments and stigma exsertion. Moreover, amiRNA VLG knock-down plants displayed unbroken stomia and septa, markedly reduced endothecium lignification, diminished ROS accumulation, and lower transcript levels of genes involved in jasmonic acid and lignin biosynthesis. The indehiscent phenotype was rescued by exogenous application of either jasmonic acid or H2O2. Altogether, our results suggest that VLG is involved in lignin and jasmonic acid biosynthesis pathways, and that proper levels of VLG are required in the process that leads to stomium breakage and anther dehiscence. Our findings shed light on the mechanisms underlying stamen development and provide new insights into the roles of a DC1 domain protein in plant reproduction. Key MessageVacuoleless Gametophytes participates in anther dehiscence through a process that involves JA, ROS and lignin accumulation.

plant biology↗

bioRxiv2022

The DC1 domain protein BINUCLEATE POLLEN is required for pollen development in Arabidopsis

Development of the male gametophyte is a tightly regulated process that requires precise control of cell division and gene expression. A relevant aspect to understand the events underlying pollen development regulation constitutes the identification and characterization of the genes required for this process. In this work we showed that the DC1 domain protein BINUCLEATE POLLEN (BNP) is essential for pollen development and germination. Pollen grains carrying the defective BNP allele failed to complete mitosis II and are impaired in pollen germination. By yeast two-hybrid analysis and bimolecular fluorescence complementation assays, we identified a set of BNP-interacting proteins. Among confirmed interactors we found NAC family transcriptional regulators Vascular Plant One-Zinc Finger 1 (VOZ1) and VOZ2. VOZ1 localization changes during pollen development, moving to the vegetative nucleus at the tricellular stage. We observed that this relocalization requires BNP, as in the absence of BNP in pollen from bnp/BNP plants, VOZ1 nuclear localization is impaired. As voz1voz2 double mutants showed the same developmental defect observed in bnp pollen grains, we propose that BNP requirement to complete microgametogenesis could be linked to its interaction with VOZ1/2 proteins. BNP could have a role of scaffold protein, recruiting VOZ1/2 to the endosomal system into assemblies that are required for their further translocation to the nucleus, where they act as transcriptional regulators. O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=180 SRC="FIGDIR/small/484815v3_fig1.gif" ALT="Figure 1"> View larger version (67K): org.highwire.dtl.DTLVardef@8680b0org.highwire.dtl.DTLVardef@6ac6fcorg.highwire.dtl.DTLVardef@2ddf1eorg.highwire.dtl.DTLVardef@193693c_HPS_FORMAT_FIGEXP M_FIG O_FLOATNOFigure 1.C_FLOATNO BNP codes for a DC1 domain containing protein. (A) Schematic view of a region of Arabidopsis chromosome 2 (from 18,323,538 to 18,321,537 bp -TAIR10) showing BNP genomic location and bnp-1 and bnp-2 insertion sites. (B) BNP amino acid sequence with boxed DC1 domains. (C) Phylogenic tree of 140 DC1 domain containing proteins in Arabidopsis. Bootstrap test results (1000 replicates) of the major nodes are indicated. IDs of sequences grouped in clusters I to VIII are listed. (D) Alignment of BNP with its closest Arabidopsis homologs and CaDC1 (AEI52549), TaCHP (ACU80555), NtDC1a (BAF80452) and NtDC1b (BAF80453). Phylogenic tree with bootstrap test results (1000 replicates) for the alignment of the complete 18 sequences is shown. Amino acid region represented for each sequence is indicated. DC1 domains are framed, signature residues and binding loop regions are indicated (C=Cys, H=His, = loop). Higher intensity in grey scale denotes higher sequence similarity. C_FIG

plant biology↗