Biology subjects

San Clemente, H.

Publications and source records attributed to San Clemente, H..

5 recordsLinked to original sources

bioRxiv2024

Cold stress involves CBF dependent regulatory pathway to remodel wood formation in Eucalyptus gunnii hybrids.

While being the most planted tree worldwide, most Eucalyptus species are sensitive to frost. Long-term exposure to cold temperatures, among other abiotic cues, triggers modification of secondary xylem differentiation in Eucalyptus, but the molecular mechanisms behind it remain unknown. Overexpression of key players of cold signalling pathway, the CRT-repeat binding factors (CBF), not only causes the expected increase in freezing tolerance but also remodels wood in a similar trend to cold acclimation, making it a good candidate for wood functional adaptation to cold stress. To gain insight in CBF role in cold-induced secondary cell wall (SCW) remodelling, we used both targeted and untargeted methodologies to show that chilling and freezing temperatures induced the deposition of a thick SCW with alterations in lignin and polysaccharides composition as well as modifications of wood anatomy in a Eucalyptus cold-tolerant hybrid. Using co-expression network approaches, we identified CBF transcription factors (TFs) as a regulatory hub in xylem cold response. Direct targets of the CBF TFs were identified by DAPseq and unravelled promising candidates involved in SCW deposition and hormonal signalling pathways. Our results shed new light on the interplay between cold response and wood formation, bringing new evidence for the role of the cell wall in trees tolerance to abiotic stresses.

plant biology↗

bioRxiv2024

C-terminally encoded peptides promoting root symbiotic nodulation in legume plants also promote the root arbuscular mycorrhizal symbiotic interaction

C-terminally encoded peptides (CEPs) are small secreted signalling peptides that promote in legumes the root nitrogen-fixing nodulation symbiosis depending on soil mineral nitrogen availability1. In Medicago truncatula, their action is mediated by the Leucine-rich repeat receptor-like protein kinase COMPACT ROOT ARCHITECTURE 2 (CRA2)2-4. As most land plants, under inorganic phosphate (Pi) limitation, M. truncatula establishes another root endosymbiotic interaction with arbuscular fungi, the arbuscular mycorrhizal symbiosis (AMS). Because this interaction is beneficial for the plant but has a high energetic cost, it is tightly controlled by host plants to limit AMS infections mainly depending on Pi availability5. We show in this study that the expression of a subset of CEP encoding genes is enhanced in the low Pi conditions that favour AMS colonization, and that overexpression of the low Pi-induced MtCEP1 gene, previously shown to promote the nitrogen-fixing root nodulation symbiosis, enhances the AMS colonization from the initial entry point of the fungi. Conversely, a loss-of-function mutation of the CRA2 receptor required for mediating CEP peptides action2 decreases the AMS interaction capacity from the same initial fungal entry stage. Transcriptomic analyses revealed that the cra2 mutant is negatively affected in the regulation of key Pi transport and response genes as well as in the biosynthesis of strigolactone (SL) hormones that are required for establishing the AMS interaction. Accordingly, SL contents were drastically decreased in cra2 mutant roots. Overall, we showed that the CEP/CRA2 pathway promotes, in legume plants, both root nodulation and AMS depending on soil mineral nutrients availability. In briefThe establishment and maintenance of root nodule and arbuscular mycorrhizal symbioses (AMS) in legume plants is tightly regulated respectively by nitrogen and phosphate availability. Pedinotti and Teyssendier de la Serve et al. show that the CEP/CRA2 pathway, previously known to promote root competence to nodulate under low nitrogen conditions, also enhances AMS establishment by controlling the expression of Pi homeostasis and strigolactone (SL) hormone biosynthesis genes, as well as SL accumulation. HighlightsO_LIA subset of M. truncatula CEP genes is induced by AMS-promoting low phosphate conditions. C_LIO_LIThe CEP1 peptides positively regulate AMS establishment, while the cra2 CEP receptor loss of function mutants display a reduced AMS colonization. C_LIO_LIThe CEP/CRA2-dependent regulation of AMS acts through downstream signals distinct from the ones involved in root nodule symbiosis regulation. The CEP/CRA2 pathway regulates AMS establishment by controlling Pi homeostasis and strigolactone (SL) hormone biosynthesis genes, as well as SL accumulation. C_LI

plant biology↗

bioRxiv2023

The Marchantia pangenome reveals ancient mechanisms of plant adaptation to the environment

Plant adaptation to a terrestrial life 450 million years ago played a major role in the evolution of life on Earth. This shift from an aquatic environment has been mostly studied by focusing on flowering plants. Here, we gathered a collection of 133 accessions of the non-vascular plants Marchantia polymorpha and studied its intraspecific diversity using selection signature analyses, genome-environment association study and a gene-centered pangenome. We identified adaptive features shared with flowering plants, such as peroxidases or nucleotide-binding and leucine-rich repeat (NLR), which likely played a role in the adaptation of the first land plants to the terrestrial habitat. The M. polymorpha pangenome also harbored lineage-specific accessory genes absent from seed plants. We conclude that different land plants lineages still share many elements from the genetic toolkit evolved by their most recent common ancestor to adapt to the terrestrial habitat, refined by lineage specific polymorphisms and gene family evolutions.

plant biology↗

bioRxiv2021

Drosophila primary microRNA-8 encodes a microRNA encoded peptide (miPEP) acting in parallel of miR-8

BackgroundRecent genome-wide studies of many species reveal the existence of a myriad of RNAs differing in size, coding potential and function. Among these are the long non-coding RNAs, some of them producing functional small peptides via the translation of short ORFs. It now appears that any kind of RNA presumably has a potential to encode small peptides. Accordingly, our team recently discovered that plant primary transcripts of microRNAs (pri-miRNAs) produce small regulatory peptides (miPEPs) involved in auto-regulatory feedback loops enhancing their cognate microRNA expression which in turn controls plant development. Here we investigate whether this regulatory feedback loop is present in Drosophila melanogaster. ResultsWe perform a survey of ribosome profiling data and reveal that many pri-miRNAs exhibit ribosome translation marks. Focusing on miR-8, we show that pri-miR-8 can produce a miPEP-8. Functional assays performed in Drosophila reveal that miPEP-8 affects development when overexpressed or knocked down. Combining genetic and molecular approaches as well as genome-wide transcriptomic analyses, we show that miR-8 expression is independent of miPEP-8 activity and that miPEP-8 acts in parallel to miR-8 to regulate the expression of hundreds of genes. ConclusionTaken together, these results reveal that several Drosophila pri-miRNAs exhibit translation potential. Contrasting with the mechanism described in plants, these data shed light on the function of yet un-described pri-microRNA encoded peptides in Drosophila and their regulatory potential on genome expression.

developmental biology↗

bioRxiv2019

An ancestral signalling pathway is conserved in plant lineages forming intracellular symbioses

Plants are the foundation of terrestrial ecosystems and their colonization of land was facilitated by mutualistic associations with arbuscular mycorrhizal fungi. Following that founding event, plant diversification has led to the emergence of a tremendous diversity of mutualistic symbioses with microorganisms, ranging from extracellular associations to the most intimate intracellular associations, where fungal or bacterial symbionts are hosted inside plant cells. Through analysis of 271 transcriptomes and 122 plant genomes, we demonstrate that the common symbiosis signalling pathway controlling the association with arbuscular mycorrhizal fungi and with nitrogen-fixing bacteria specifically co-evolved with intracellular endosymbioses, including ericoid and orchid mycorrhizae in angiosperms and ericoid-like associations of bryophytes. In contrast, species forming exclusively extracellular symbioses like ectomycorrhizae or associations with cyanobacteria have lost this signalling pathway. This work unifies intracellular symbioses, revealing conservation in their evolution across 450 million years of plant diversification.

plant biology↗