Biology subjects

Adriano Batista, R.

Publications and source records attributed to Adriano Batista, R..

3 recordsLinked to original sources

bioRxiv2026

Fast zygotic genome activation in brown algae

The maternal-to-zygotic transition (MZT), during which developmental control shifts from maternal products to the zygotic genome, is a fundamental feature of embryogenesis. The prevailing model, established from animal systems, holds that maternal provisioning and nuclear-to-cytoplasmic (N/C) ratio determine the timing of zygotic genome activation (ZGA). Whether this developmental logic is conserved across multicellular eukaryotes remains unknown. Using brown algae, an independently evolved multicellular lineage spanning broad natural variation in maternal provisioning, we generated comparative embryonic transcriptomes across three species and resolved parental contributions through reciprocal crosses and allele-specific expression. Contrary to canonical animal models, all species activated their zygotic genomes immediately after fertilisation, including highly provisioned species with low N/C ratios, and showed no evidence of stable parental imprinting. These findings reveal that timing and regulation of MZT during embryogenesis is evolutionarily flexible and independently shaped across the tree of life.

developmental biology↗

bioRxiv2026

PKN is a sex- and species-specific fertilization factor in brown algae

Fertilization, the union of male and female gametes, is central to sexual reproduction, yet the molecular mechanisms that ensure partner recognition and enforce species specificity remain elusive. Here we identify PKN, a previously uncharacterized transmembrane protein expressed exclusively in female gametes of brown algae, as an essential determinant of fertilization. Loss of PKN abolishes fertilization without affecting earlier mating steps, including gamete attraction, placing its function as a key mediator of male-female recognition. PKN contains extracellular {beta}-propeller and mucin-like domains that are enriched in predicted glycosylation sites and rapidly evolving, consistent with a role in species-specific cell-cell recognition. Notably, PKN enforces reproductive isolation within the genus Scytosiphon by preventing interspecific fertilization. Together, these findings uncover a female-encoded recognition mechanism in brown algae and reveal protein-glycan interfaces as a conserved strategy for enforcing sex- and species-specific fertilization across Eukaryotes.

developmental biology↗

bioRxiv2024

The evolutionary history and functional specialization of microRNA genes in Arabidopsis halleri and A. lyrata

MicroRNAs (miRNAs) are a class of small non-coding RNAs that play important regulatory roles in plant genomes. While some miRNA genes are deeply conserved, the majority appear to be species-specific, raising the question of how they emerge and integrate into cellular regulatory networks. To better understand this, we first performed a detailed annotation of miRNA genes in the closely related plants Arabidopsis halleri and A. lyrata and evaluated their phylogenetic conservation across 87 plant species. We then characterized the process by which newly emerged miRNA genes progressively acquire the properties of "canonical" miRNA genes, in terms of size and stability of the hairpin precursor, loading of their cleavage products into Argonaute proteins, and potential to regulate downstream target genes. Nucleotide polymorphism was lower in the mature miRNA sequence than in the other parts of the hairpin (stem, terminal loop), and the regions of coding sequences targeted by miRNAs also had reduced diversity as compared to their neighboring regions along the genes. These patterns were less pronounced for recently emerged than for evolutionarily conserved miRNA genes, suggesting a weaker selective constraint on the most recent miRNA genes. Our results illustrate the rapid birth-and-death of miRNA genes in plant genomes, and provide a detailed picture of the evolutionary processes by which a small fraction of them eventually integrate into "core" biological processes.

evolutionary biology↗