Biology subjects

Costa, M. M. R.

Publications and source records attributed to Costa, M. M. R..

9 recordsLinked to original sources

bioRxiv2026

Recurrent Hermaphroditism and Sex-Biased ABCDE Gene Expression Reveal Latent Floral Plasticity in the Pedunculate Oak Lineage (Q.robur s.l.)

Background and AimsThe development of unisexual flowers relies on the tight coordination of flower organ identity and sex determination. The genus Quercus is typically considered strictly monoecious, bearing fully segregated male and female flowers within the same individual tree. However, several reports of atypical flowering across the genus challenge this canonical view, suggesting that flowering in oaks may be more flexible than traditionally assumed. In this work, the dynamics of flower development in Quercus orocantabrica were examined to correlate contrasting floral morphologies with divergent molecular profiles. MethodsThe flowering phenology of Q. orocantabrica trees was closely monitored over several individuals and years, together with a detailed floral morphological analysis of male, female and atypical flowers. Key floral homeotic gene homologues were identified, and their expression assayed in the development of different flowers. Key ResultsRecurrent and widespread hermaphroditic flowering was detected in several Q. orocantabrica trees, frequently associated with unseasonal flowering events. Gene expression analysis of male, female and hermaphroditic flowers revealed a sex-biased expression of Q. orocantabrica B- and C-class genes, with the B-class gene QoPI in particular being tightly associated with the presence of fully-developed stamens. In addition, the expression of the C-class gene QoSHP contrasted with reports in other Fagaceae, highlighting a potential functional divergence of the C/D-class lineage within the family. ConclusionsThe results here depicted indicate that the dynamics of floral sex identity in oaks are more plastic than traditionally assumed, supporting a reinterpretation of oak reproductive biology based on a versatile and resilient framework responsive to different developmental contexts.

plant biology↗

bioRxiv2026

AGP-Ca2+ binding is essential for pollen development and pollen tube growth in Arabidopsis thaliana

Arabinogalactan-proteins (AGPs) are highly glycosylated cell wall proteins essential for plant reproduction, although their mode of action remains unclear. AGPs have been proposed to bind and store calcium (Ca2+) in the apoplast via glucuronic acid (GlcA) residues added by glucuronosyltransferases (GLCATs), potentially acting as Ca2+ capacitors. Here we report that Ca2+ binding by AGPs is required for successful double fertilisation in Arabidopsis. Analysis of glcat14a glcat14b glcat14d triple mutants revealed reduced seed set due to the abortion of pollen grains, which lacked cytoplasmic content and an intine layer, as confirmed by the absence of cellulose, resembling the phenotype of AGP-deficient mutants. When grown under Ca2+-deficient conditions, GLCAT mutants showed exacerbated and conditional reproductive defects that were attenuated under standard Ca2+ conditions. Our findings establish a functional requirement for GlcA-mediated Ca2+ binding by AGPs and support their role as apoplastic Ca2+ stores essential for male fertility and reproductive success in plants.

plant biology↗

bioRxiv2025

Antirrhinum flower shape: unravelling gene expression across developmental axes and boundaries

O_LIZygomorphic flowers in Antirrhinum majus arise from coordinated patterning along the dorsoventral and proximal-distal axes, but the transcriptional programs that pattern these axes to generate the complex corolla morphology remain poorly understood. C_LIO_LIWe performed comparative transcriptomic analyses of dorsal and ventral petals across developmental stages, combined with expression profiling in floral symmetry mutants, to identify genes potentially associated with dorsal identity (AmCYC-dependent) and ventral identity (AmDIV-dependent), and to map their spatial dynamics along the proximal-distal axis. Axis-specific and boundary-localized expression patterns were validated by in situ hybridisation. C_LIO_LIWe identified dorsal-specific candidate targets of AmCYC and ventral-specific genes regulated by AmDIV, including factors with regionally restricted expression along the proximal-distal axis. We further found that a conserved NGATHA-LIKE1-BRASSINAZOLE-RESISTANT 1-miR164 module, known for primordia growth regulation in Arabidopsis, has been co-opted in Antirrhinum to act as a potential spatiotemporal regulator of AmCUP, a target of AmDIV, thereby contributing to the complex shape of the Antirrhinum flower. C_LIO_LIOur results provide new insight into the gene regulatory landscape underlying zygomorphic flower development and highlight specific regulatory modules that may coordinate axis patterning with boundary establishment in the corolla. This work establishes a framework for further understanding how developmental gene networks shape a complex corolla morphology and offers new targets for functional and evolutionary investigation of floral diversity. C_LI

plant biology↗

bioRxiv2024

Molecular control of dormancy transitions throughout the year in the monoecious cork oak

Bud dormancy plays a vital role in flowering regulation and fruit production, being highly regulated by endogenous and environmental cues. Deployment of epigenetic modifications and differential gene expression control bud dormancy/break cycles. Information on how these genetic and epigenetic mechanisms are regulated throughout the year is still scarce for temperate trees, such as Quercus suber. Here, the expression levels of QsCENL and QsDYL1 during different seasonal cycles of bud development suggest that QsCENL may be implicated in the establishment of growth cessation in Q. suber and that QsDYL1 is a good dormancy marker. Moreover, the analysis of the profiles of epigenetic marks and the expression of modifiers, in dormant versus non-dormant bud meristems, indicate that epigenetic regulation is implicated in how bud development progresses in Q. suber. The identification of bud specific mechanisms opens new possibilities to understand how trees respond to challenging environmental signals derived from climate change.

plant biology↗

bioRxiv2023

Lectins in pistils play a key role in self-incompatibility in the heterostylous Linum perenne

Self-incompatibility is one of the mechanisms preventing inbreeding in populations, based on the failure of pollen grains to germinate or of pollen tubes to grow normally in incompatible crosses. A unique model for studying this process are heterostylous species, in which self-incompatibility alleles are closely linked to flower morphological traits. One such species is L. perenne, a classic distylous species with reciprocal herkogamy and complete self-incompatibility strongly linked. The mechanism of self-pollen recognition is poorly understood in most heterostylous species, including L. perenne. As self-incompatibility in other systems is based on protein-protein interactions and many extracellular proteins are glycosylated, one of the possible participants in this process may be lectins. Therefore, we aimed to investigate the lectin activity in pistils and stamens of L. perenne L-morph and S-morph plants and to establish whether these lectins take part in self-incompatibility. We show that pistil-derived galactose-specific Ca2+-independent lectins from the respective other morph can overcome self-incompatibility in heterostylous L. perenne. This may be due to the presence of some lectins that are specific for arabinose and xylose. Our results suggest that lectins participate in signaling pathways for recognition at the pollen-stigma interface and are involved in the regulation of the self-incompatibility process in L. perenne.

plant biology↗

bioRxiv2020

RNA editing in inflorescences of wild grapevine unveils association to sex and development

RNA editing challenges the central dogma of molecular biology, by modifying the genetic information at the transcription level. Recent reports, suggesting increased levels of RNA editing in plants, raised questions on the nature and dynamics of such events during development. We here report the occurrence of distinct RNA editing patterns in wild Vitis flowers during development, with twelve possible RNA editing modifications observed for the first time in plants. RNA editing events are gender and developmental stage specific, identical in subsequent years of this perennial species and with distinct nucleotide frequencies neighboring editing sites on the 5 and 3 flanks. The transcriptome dynamics unveils a new regulatory layer responsible for gender plasticity enhancement or underling dioecy evolution in Vitis.

plant biology↗

bioRxiv2020

Portuguese wild grapevine genome re-sequencing (Vitis vinifera sylvestris)

Vitis is a relevant genus worldwide. The genome of a Vitis vinifera representative (PN40024) published in 2007 boosted grapevine related studies. While this reference genome is a suitable tool for the overall studies in the field, it lacks the ability to unveil changes accumulated during V. vinifera domestication. Considering that grapevines for wine production (V. v. vinifera, hereafter vinifera) have evolved from V. v. sylvestris (hereafter sylvestris), or from a shared no-longer existing ancestor, both subspecies are quite close, but sylvestris has not been domesticated and still exist nowadays, preserving wild characteristics, making it a good material to provide insights into vinifera domestication. The difference in the reproductive strategy between both subspecies is one of the characteristics that sets them apart. While vinifera flowers are hermaphrodite with functional male and female organs, sylvestris is mostly dioecious. Male plants present flowers lacking functional carpels unable to produce grapes and female individuals have flowers with reflexed stamens producing infertile pollen but able to exhibit small and acidic grapes. In this paper, we describe the re-sequencing of the genomes from a male and a female individual of the wild sylvestris and its comparison against the reference vinifera genome.

plant biology↗

bioRxiv2020

Genome-Wide Identification of Epigenetic Regulators in Quercus suber

Modifications of DNA and histones, including methylation and acetylation, are critical for the epigenetic regulation of gene expression during plant development, particularly during environmental adaptation processes. However, information on the enzymes catalyzing all these modifications in perennial trees, such as Quercus suber, is still not available. In this study, several epigenetic modifier proteins, including eight DNA methyltransferases (DNA Mtases), three DNA demethylases (DDMEs) and ninety-one histone modifiers including thirty-five histone methyltransferases (HMTs), twenty-six histone demethylases (HDMTs), eight histone acetyltransferases (HATs) and twenty-two histone acetylases (HDACs) were identified in Q. suber. Phylogenetic analyses of the DNA and histone modifier proteins were performed using several plant species homologs, enabling the classification of the Q. suber proteins. Additional in silico analysis showed that some Q. suber DNA Mtases, DMEs and histone modifiers have the typical domains found in the plant model Arabidopsis, which might suggest a conserved functional role. A link between the expression levels of each gene in different Q. suber tissues (buds, flowers, acorns, embryos, cork and roots) with the functions already known for their closest homologs in other species was also established. Therefore, the data generated here are important for future studies exploring the role of epigenetic regulators in this economically important species.

genomics↗

bioRxiv2020

Unisexual flower initiation in the monoecious Quercus suber L., a molecular approach

Several plant species display a temporal separation of the male and female flower organ development to enhance outbreeding, however, little is known regarding the genetic mechanisms controlling this temporal separation. Quercus suber is a monoecious oak tree with accentuated protandry: in late winter, unisexual male flowers emerge adjacent to the swollen buds, whereas unisexual female flowers emerge in the axils of newly formed leaves formed during spring (4 to 8 weeks after male flowering). Here, phylogenetic profiling lead to the identification of cork oak homologs of key floral regulatory genes. The role of these cork oak homologs during flower development was identified with functional studies in Arabidopsis thaliana. The expression profile of flower regulators (inducers and repressors) throughout the year, in leaves and buds, suggests that the development of male and female flowers may be preceded by separated induction events. Female flowers are most likely induced during the vegetative flush occurring in spring, whereas male flowers may be induced in early summer, staying enclosed within the pre-dormant buds, but complete their development before the vegetative flush of the following year, displaying a long period of anthesis that spans the dormant period. Results portray a genetic mechanism that may explain similar reproductive habits in other tree species.

plant biology↗