Biology subjects

Carretero-Paulet, L.

Publications and source records attributed to Carretero-Paulet, L..

4 recordsLinked to original sources

bioRxiv2023

Spatial and temporal characterization of the rich fraction of plastid DNA present in the nuclear genome of Moringa oleifera reveals unanticipated complexity in NUPTs' formation

Beyond the massive amounts of DNA and genes transferred from the protoorganelle genome to the nucleus during the endosymbiotic event that gave rise to the plastids, stretches of plastid DNA of varying size are still being copied and relocated to the nuclear genome in a process that is ongoing and does not result in the concomitant shrinking of the plastid genome. As a result, plant nuclear genomes are featured by a small, but variable, fraction of their genomes of plastid origin, the so-called nuclear plastid DNA sequences (NUPTs). However, research on the topic was mostly focused on a limited number of species and of plastid DNA. Here, we leveraged a chromosome-scale version of the Moringa oleifera genome, featured by the largest fraction of plastid DNA in any plant nuclear genome, to examine the chromosomal distribution and arrangement of NUPTs, to explicitly model and test the correlation between their age and size distribution, as well as to characterize their sites of origin at the chloroplast genome and their sites of insertion at the nuclear one. We found a bimodal distribution of NUPT relative ages, which implies NUPTs in moringa were formed through two separate events. Furthermore, NUPTs from every event showed markedly distinctive features, suggesting they originated through distinct mechanisms. Our results reveal an unanticipated complexity of the mechanisms at the origin of NUPTs and of the evolutionary forces behind their fixation and highlight moringa species as an exceptional model to study the mechanisms of origin and evolutionary fate of NUPTs. Significance statementSequencing of plant genomes has revealed the presence of a variable, but significant, content of DNA arising from their organelles, i.e., plastids and mitochondria. However, the mechanisms underlying their origin and fixation are not yet fully elucidated. Here, by thoroughly examining the spatial and temporal distribution of the large fraction of plastid DNA present in the nuclear genome of the orphan crop Moringa oleifera, we identified their episodic origin trough seemingly distinct mechanisms, highlighting the complexity of the molecular and evolutionary dynamics underlying their origin and fixation and revealing moringa as an outstanding model to assess the impact of plastid DNA in the evolution of the architecture and function of plant nuclear genomes.

genomics↗

bioRxiv2020

Evolution of molecular determinants for SUMO-activating enzyme subcellular localization in plants

Post-translational modification by Small Ubiquitin-related Modifier (SUMO) is an essential regulatory mechanism in eukaryotes. In the cell, SUMO conjugates are highly enriched in the nucleus and, consistently, SUMOylation machinery components are mainly nuclear. Nonetheless, cytosolic SUMO targets also exist and the mechanisms that facilitate SUMO conjugation in the cytosol are unknown. Here, we show that the nuclear localization of the Arabidopsis SUMO activating enzyme large subunit SAE2 is dependent on two nuclear localization signals, the canonical NLS1 and the non-canonical NLS2 identified and validated here. NLS2 is proteolytic processed from SAE2 during seed development, facilitating SAE2 enrichment in the cytosol. Results obtained using transgenic plants expressing different SAE2 proteoforms suggest that SAE2 cytosolic enrichment could constitute a rapid signal for growth arrest. Phylogenetic studies indicated that the Arabidopsis NLS1-NLS2 structural organization is conserved only in seed plants, providing a potential evolutionary role of cytosolic SUMOylation in seed appearance.

biochemistry↗

bioRxiv2019

The Avocado Genome Informs Deep Angiosperm Phylogeny, Highlights Introgressive Hybridization, and Reveals Pathogen Influenced Gene Space Adaptation

The avocado, Persea americana, is a fruit crop of immense importance to Mexican agriculture with an increasing demand worldwide. Avocado lies in the anciently-diverged magnoliid clade of angiosperms, which has a controversial phylogenetic position relative to eudicots and monocots. We sequenced the nuclear genomes of the Mexican avocado race, P. americana var. drymifolia, and the most commercially popular hybrid cultivar, Hass, and anchored the latter to chromosomes using a genetic map. Resequencing of Guatemalan and West Indian varieties revealed that [~]39% of the Hass genome represents Guatemalan source regions introgressed into a Mexican race background. Some introgressed blocks are extremely large, consistent with the recent origin of the cultivar. The avocado lineage experienced two lineage-specific polyploidy events during its evolutionary history. Although gene-tree/species-tree phylogenomic results are inconclusive, syntenic ortholog distances to other species place avocado as sister to the enormous monocot and eudicot lineages combined. Duplicate genes descending from polyploidy augmented the transcription factor diversity of avocado, while tandem duplicates enhanced the secondary metabolism of the species. Phenylpropanoid biosynthesis, known to be elicited by Colletotrichum (anthracnose) pathogen infection in avocado, is one enriched function among tandems. Furthermore, transcriptome data show that tandem duplicates are significantly up- and down-regulated in response to anthracnose infection, whereas polyploid duplicates are not, supporting the general view that collections of tandem duplicates contribute evolutionarily recent \"tuning knobs\" in the genome adaptive landscapes of given species.\n\nSIGNIFICANCE STATEMENTAvocado is a nutritious, economically important fruit species that occupies an unresolved position near the earliest evolutionary branchings of flowering plants. Our nuclear genome sequences of Mexican and Hass variety avocados inform ancient evolutionary relationships and genome doublings, the admixed nature of Hass, and provide a look at how pathogen interactions have shaped avocados more recent genomic evolutionary history.

genomics↗

bioRxiv2019

Using digital organisms to investigate the effect of whole genome duplication in (artificial) evolution

The potential role of whole genome duplication (WGD) in evolution is controversial. Whereas some view WGD mainly as detrimental and an evolutionary dead end, there is growing evidence that the long-term establishment of polyploidy might be linked to environmental change, stressful conditions, or periods of extinction. However, despite much research, the mechanistic underpinnings of why and how polyploids might be able to outcompete non-polyploids at times of environmental upheaval remain indefinable. Here, we improved our recently developed bio-inspired framework, combining an artificial genome with an agent-based system, to form a population of so-called Digital Organisms (DOs), to examine the impact of WGD on evolution under different environmental scenarios mimicking extinction events of varying strength and frequency. We found that, under stable environments, DOs with non-duplicated genomes formed the majority, if not all, of the population, whereas the numbers of DOs with duplicated genomes increased under dramatically challenging environments. After tracking the evolutionary trajectories of individual artificial genomes in terms of sequence and encoded gene regulatory networks (GRNs), we propose that increased complexity, modularity, and redundancy of duplicated GRNs might provide DOs with increased adaptive potential under extinction events, while ensuring mutational robustness of the whole GRN. Our results confirm the usefulness of our computational simulation in studying the role of WGD in evolution and adaptation, helping to overcome the traditional limitations of evolution experiments with model organisms, and provide some additional insights into how genome duplication might help organisms to compete for novel niches and survive ecological turmoil.

evolutionary biology↗