About

Verónica Di Stilio is a professor in the Department of Biology at the University of Washington. Her research investigates how plants evolved their incredible diversity, with a particular focus on the development of flowers and pollination strategies such as wind pollination. Her work explores how organisms often reuse existing genes in new ways, a process called gene co-option, to create new forms and functions. By working with a wide range of plants—from flowering species to ferns and gymnosperms—she aims to uncover how the genetic toolkit for flowers existed long before flowers themselves, helping to explain key innovations in plant evolution. Verónica Di Stilio completed her undergraduate studies in Biology at the University of Buenos Aires, specializing in Plant Ecology. She then earned her Ph.D. in Plant Biology from the University of Massachusetts Amherst, where she worked on plant sex chromosome evolution. Her postdoctoral training included research on pollen gene expression and the role of floral transcription factors, as well as the field of Evolution of Development (Evo-Devo) at Harvard University. She joined the faculty of the Department of Biology at the University of Washington in 2003 and continues to pursue her interests in the evolution of plant development, especially flowering. She has taught courses such as Plant Evolution and Genetics of Plant Innovations, and has received awards including the J. William Fulbright Foreign Scholar and National Geographic Explorer.

Research topics

• Genetics
• Biology
• Botany
• Evolutionary biology
• Ecology
• Epistemology

Selected publications

• From Candidate Genes to Macroevolution: An Integrated Approach to Modeling the Evolution of Plant Innovations

  Integrative and Comparative Biology · 2026-01-01 · 1 citations

  articleSenior author

  Understanding how plant innovations arise and persist requires connecting mechanisms across biological scales. The growing accessibility of genomic data and methodological advances in phylogenetic comparative methods provide unprecedented opportunities to achieve this integration. Yet, functional tools remain unevenly distributed across the plant Tree of Life, and conceptual differences across scales of inquiry limit integration. Here, we highlight emerging approaches that bridge developmental, genomic, and macroevolutionary research to generate a more comprehensive view of plant evolution. We propose building a "Functional Tree of Plant Life" by investing in shared infrastructure and funding programs for developing transformation techniques and building genetic resources to incentivize research in nonmodel taxa. Concurrently, further methodological advances in phylogenetic comparative methods are needed to continue accommodating complex developmental, genomic, and transcriptomic data. Combined, these efforts would enable experimental validation of gene function across diverse lineages and improve reconstructions of the evolution of genetic pathways and the developmental origins of key phenotypes. Building this integrative framework will require both conceptual synthesis, collaboration, and community investment but offers a transformative path toward understanding the evolution of plant form and function.

  PublisherDOI

• Florigen and antiflorigen gene expression correlates with reproductive state in a marine angiosperm, Zostera marina

  iScience · 2025-07-08 · 2 citations

  articleOpen access

  may inhibit flowering in eelgrass.

  PublisherDOI

• Enabling the study of gene function in gymnosperms: Virus‐induced gene silencing in <i>Ephedra tweedieana</i>

  Applications in Plant Sciences · 2025-12-02

  articleOpen accessSenior authorCorresponding

  Abstract Premise As the sister clade to angiosperms, extant gymnosperms are crucial for reconstructing ancestral gene regulatory networks in seed plants. This highlights the need for model systems representing each of their distinct lineages. However, tools to quickly and effectively investigate gene function in gymnosperms are still limited due to the challenges of long life cycles and large genome sizes. Species within the xerophytic genus Ephedra (Gnetales) have comparatively smaller genomes and shrubby growth habits with shorter life spans, making them better suited for greenhouse cultivation and laboratory experiments. Methods We implement virus‐induced gene silencing (VIGS) to manipulate gene expression in Ephedra tweedieana via Agrobacterium ‐mediated vacuum infiltration of tobacco rattle virus (TRV1 and TRV2) into seedlings. Results Treatment resulted in highly efficient gene silencing of the E. tweedieana PHYTOENE DESATURASE ( PDS ) ortholog EtwPDS . The expected photobleaching phenotype was observed as early as two weeks, and lasted at least five months in stems, shoot tips, leaves, axillary meristems, and lateral branches of treated plants. Discussion We report on virus‐induced targeted gene silencing of PDS in a Gnetales representative to further enable functional studies of the genetic mechanisms underpinning adaptations in gymnosperms, an important and underrepresented lineage of seed plants.

  PublisherOA PDFDOI

• <i>LEAFY</i> demonstrates functions in reproductive development of the gametophyte but not the sporophyte of the fern <i>Ceratopteris richardii</i>

  Development · 2025-11-25 · 3 citations

  articleOpen accessSenior author

  Flowers are a key reproductive innovation of the angiosperms. Seed plant reproductive axes (including flowers) evolved as reproductively specialized shoots of the land plant diploid sporophyte, with the gamete-producing haploid gametophyte becoming reduced and enclosed within ovules and microsporangia. The transcription factor LEAFY (LFY) initiates floral development, yet it predates flowers and is found across all land plants. LFY function outside angiosperms is known from the moss Physcomitrium patens, where it controls the first cell division of the sporophyte, and from the model fern Ceratopteris richardii, a seedless vascular plant where CrLFY1 and CrLFY2 maintain vegetative meristem activity. However, how LFY's floral role evolved remains unclear. Using over-expression, we uncover new roles for CrLFY1/2 in fern gametophyte reproduction, in sperm cells and in the gametophyte's multicellular notch meristem. While no sporophytic reproductive function was detected in terms of time to sporing, over-expression supports a role in frond compounding and in the zygote's first cell division. Our findings suggest a potentially ancestral LFY function in fern haploid-stage reproduction, which might have been co-opted into the sporophyte during the origin of the flower.

  PublisherOA PDFDOI

• Enabling the Study of Gene Function in Gymnosperms: VIGS in <i>Ephedra tweedieana</i>

  bioRxiv (Cold Spring Harbor Laboratory) · 2025-02-08 · 1 citations

  preprintOpen accessSenior authorCorresponding

  ABSTRACT Premise As the sister clade to angiosperms, gymnosperms are key to enabling the reconstruction of ancestral gene regulatory networks for seed plants. However, tools to rapidly and efficiently investigate gene function in gymnosperms remain limited due to the challenges of long life cycles and large genome sizes. Species within the xerophytic genus Ephedra (Gnetales) have comparatively smaller genomes and shrubby growth habits with shorter life spans, making them better suited for greenhouse cultivation and laboratory experiments. Methods and Results Here, we implement Virus-Induced Gene Silencing (VIGS) to manipulate gene expression in Ephedra tweedieana. Agrobacterium -mediated vacuum infiltration of Tobacco Rattle Virus (TRV2 and TRV1) in seedlings resulted in highly efficient silencing of the E. tweedieana PHYTOENE DESATURASE ortholog EtwPDS . The expected photobleaching phenotype was observed as early as two weeks. It lasted at least three months, in stems, shoot tips, leaves, axillary meristems, and lateral branches of treated plants. Conclusions This first report of transient transformation and targeted gene silencing in a gymnosperm will further enable functional studies of the genetic mechanisms underpinning adaptations in this important and underrepresented lineage of seed plants.

  PublisherOA PDFDOI

• <i>LEAFY</i> demonstrates ancestral reproductive functions in the gametophyte and not the sporophyte of the fern <i>Ceratopteris richardii</i>

  bioRxiv (Cold Spring Harbor Laboratory) · 2025-03-24

  preprintOpen accessSenior authorCorresponding

  Abstract Flowers are a key reproductive innovation of the angiosperms. They evolved as a modification of the ancestral plant life cycle whereby the haploid gamete-producing generation (gametophyte) became enclosed within the diploid, spore-producing generation (sporophyte). The transcription factor LEAFY ( LFY ) initiates angiosperm floral development, yet its lineage predates flowers and is found across all land plants. LFY function outside angiosperms is known from the moss Physcomitrium patens , where they control the first division of the sporophyte, and from the model fern Ceratopteris richardii , a vascular plant without seeds or flowers, where CrLFY1 and CrLFY2 maintain vegetative meristem activity. However, how LFY’ s reproductive role evolved remains unclear. Using over-expression, we uncover new roles for CrLFY1/2 in fern gametophyte reproduction, particularly in sperm cells and in the gametophyte’s multicellular notch meristem. No sporophytic reproductive function was detected, but over-expression supports a role in fern frond compounding and a conserved role in the zygote’s first division. Our findings highlight an ancestral LFY function in fern haploid-stage reproduction, which may have been co-opted into the sporophyte during the origin of the flower. Summary Statement The origin of LEAFY ’s floral function is unknown, with only vegetative roles known from seedless plants. We identify ancestral reproductive roles for the first time, unexpectedly in the fern gametophyte.

  PublisherOA PDFDOI

• Editorial: Model organisms in plant developmental biology—their effectiveness and limitations

  Frontiers in Plant Science · 2024-09-13 · 2 citations

  editorialOpen access1st authorCorresponding

  Model organisms represent an invaluable resource for fundamental and applied research, allowing the iden=fica=on of the mechanis=c basis of evolu=onary innova=ons. This ar=cle collec=on showcases studies performed on established and emerging model organisms in plant developmental biology that have broad significance to the field. Classically used for gene=c and molecular studies in Plant Biology, model organisms are progressively entering many subdisciplines within Plant Development and EvoDevo. Increased phylogene=c breadth and availability of genomes and transgenic techniques have fostered many innova=ve ideas and syntheses spanning the range from fossil analyses to single-cell sequencing. However, broad taxonomic applicability of the knowledge gained from studies on model organisms, and relevance to the field of EvoDevo oRen remains unresolved. To address such ques=ons, this research topic focuses on new insights, latest discoveries, current challenges, and future perspec=ves on the use of model organisms, and the extent to which the knowledge gained from them can be extrapolated. Authors were encouraged to iden=fy the greatest unifying concepts in their sub-disciplines, as well as to put forward poten=al solu=ons to address the challenges emerging from the use of model plants.There is s=ll much to be learned in the classic core eudicot model Arabidopsis thaliana, such as descrip=on of a novel signaling pathway used by plant elicitor pep=des to regulate root hair development (Jing et al, 2024). Cleome violacea (Cleomaceae), in the sister lineage to Brassicaceae, u=lizes comparisons to Arabidopsis to illuminate conserved gene=c pathways in the evolu=on of nectary development, sugges=ng a unique origin of nectaries in these sister lineages, while adding a reference point to only four other core eudicots with func=onal data on this aspect of flower development (Carey et al, 2023). Economically significant models: In the dicot model crop co]on (Gossypium hirsutum, Malvaceae), novel insights were gained on the role of the floral E class genes, the MADS box transcrip=on factors SEPALLATA. Via targeted gene silencing combined with heterologous overexpression in Arabidopsis, the authors find that the co]on orthologs GhSEP interact with regulators of the transi=on to flowering such as GhAP1 and GhLFY, leading them to propose a model of tetramer interac=on in leaves, meristems and floral organs (Chen et al, 2023). And in the model tree poplar (Salicaceae), Li et al, 2023 demonstrate that two BLADE ON PETIOLE orthologs func=on in secondary growth affec=ng wood produc=on, via heterologous overexpression in Arabidopsis. In the monocot model crop maize, the ubiquitous developmental regulators GF14 emerged as candidates for plant height from gene regulatory network analyses. Heterologous tes=ng via over-expression in Arabidopsis resulted in decreased plant height providing further evidence that these genes are involved in regula=ng plant growth that directly impacts crop yield (Wang et al, 2024). The widespread stem parasi=c plants in the Cuscuta genus offer a unique model to inves=gate this divergent plant growth strategy that results in enormous loss in agricultural fields. The authors present the advantages of using Cuscuta species as model organisms to illuminate the haustorium forma=on process using unique features such as self, hyper-, and cross-organ parasi=sm (Jhu and Sinha, 2022).The order Ranunculales occupies an interes=ng phylogene=c posi=on as an early-diverging eudicot and sister group to the core eudicots; four representa=ves of this order, encompassing two families, are included in this collec=on. The iconic state flower California poppy (Eschscholzia californica, Papaveraceae) is an emerging model with a genome in the making and the ability to conduct transient gene silencing. California poppy promises to help integrate tradi=onal enquiries into the regula=on of morphogenesis with emerging interest in secondary metabolites, due to its abundance of benzylisoquinoline alkaloids in floral organs (Becker et al, 2023). Thalictrum thalictroides (Ranunculaceae), is amenable to high efficiency targeted gene silencing. Combined with gene duplica=on from mul=ple rounds of polyploidy in the genus and expression analyses, the authors demonstrate the mul=ple roles of the MYB transcrip=on factor family MIXTA-like and bridge the gap to reconstruct its ancestral func=on. In addi=on to its previously demonstrated role in papillate cells on the floral perianth, the authors demonstrate its involvement in leaf trichome development in T. thalictroides. Heterologous over-expression in tobacco demonstrates a conserved trichome func=on, suppor=ng the dual role in the eudicot ancestor, presumably later parsed into dis=nct paralogs (Zahid et al 2023). Damerval et al, 2024 characterize the land plant specific TCP family of transcrip=on factors in Nigella damascena (Ranunculaceae). On the one hand, the authors iden=fy six clades of Class I TCP genes in Nigella likely tracing back to the origin of angiosperms, and three clades of Class II TCP with mostly redundant expression. On the other hand, the CYC/TB1 lineage are expressed dis=nctly, sugges=ng more specific roles. Sharma et al (2024) review the unique ways in which the Delphinieae tribe, another Ranunculaceae model clade, contributes to understanding of the evolu=on, ecology and development of complex flower symmetry involving a hyperorgan of synorganized petaloid spurred organs.In non-flowering seed plants (gymnosperms), where very few model systems have been developed, Tang et al (2022) characterize a Ginkgo biloba variety with a range of abnormal leaf shapes, from needle to trumpet-like. The authors find anatomical and gene=c evidence for changes in leaf polarity via shiRs in the adaxial (dorsal) and abaxial (ventral) domains, in combina=on with boundary defects resul=ng in =ssue fusion.Two ar=cles highlight representa=ves of the non-vascular bryophytes, a liverwort and a hornwort. Singh and Bowman (2023) introduce us to the enigma=c Ricciocarpos natans, a liverwort that has secondarily evolved to be aqua=c and monoicous from ancestral dioicy with sex chromosomes. R. natans thus provides an excellent plahorm to inves=gate the genomic consequences of sexual system and life habit transi=ons, while also broadening the land plant

  PublisherOA PDFDOI

• Florigen and antiflorigen gene expression correlates with reproductive state in a marine angiosperm, <i>Zostera marina</i>

  bioRxiv (Cold Spring Harbor Laboratory) · 2024-11-11

  preprintOpen access

  SUMMARY Florigen and antiflorigen genes within the phosphatidylethanolamine-binding protein (PEBP) family regulate flowering in angiosperms. In eelgrass ( Zostera marina ), a marine foundation species threatened by climate change, flowering and seed production are crucial for population resilience. Yet, the molecular mechanism underpinning flowering remains unknown. Using phylogenetic analysis and functional assays in Arabidopsis , we identified thirteen PEBP genes in Z. marina ( ZmaPEBP ) and showed that four genes altered flowering phenotypes when overexpressed. We used quantitative RT-PCR on Z. marina shoots from perennial and annual populations in Willapa Bay, USA to assess expression of these four genes in different tissue and expression changes throughout the growth season. We demonstrated that ZmaFT2 and ZmaFT4 promote flowering, and ZmaFT9 and ZmaTFL1a repress flowering in Arabidopsis . Across five natural sites exhibiting different degrees of population genetic structure, ZmaFT2 and ZmaFT4 were expressed in leaves of vegetative and reproductive shoots and in stems and rhizomes of reproductive shoots. ZmaFT9 was distinctively expressed in leaves of vegetative and juvenile shoots, while ZmaTFL1a levels increased after flowering shoots emerged. Our results suggest that ZmaFT2 and ZmaFT4 may promote flowering, while ZmaFT9 may inhibit a floral transition in eelgrass. We speculate that ZmaTFL1a may be involved in flowering shoot architecture.

  PublisherOA PDFDOI

• Flower morphology as a predictor of pollination mode in a biotic to abiotic pollination continuum

  Annals of Botany · 2023-05-26 · 9 citations

  articleOpen accessSenior author

  BACKGROUND AND AIMS: Wind pollination has evolved repeatedly in flowering plants, yet the identification of a wind pollination syndrome as a set of integrated floral traits can be elusive. Thalictrum (Ranunculaceae) comprises temperate perennial herbs that have transitioned repeatedly from insect to wind pollination while also exhibiting mixed pollination, providing an ideal system to test for evolutionary correlation between floral morphology and pollination mode in a biotic to abiotic continuum. Moreover, the lack of floral organ fusion across this genus allows testing for specialization to pollination vectors in the absence of this feature. METHODS: We expanded phylogenetic sampling in the genus from a previous study using six chloroplast loci, which allowed us to test whether species cluster into distinct pollination syndromes based on floral morphology. We then used multivariate analyses on floral traits followed by ancestral state reconstruction of the emerging flower morphotypes and determined whether these traits are evolutionarily correlated under a Bayesian framework with Brownian motion. KEY RESULTS: Floral traits fell into five distinct clusters, which were reduced to three after considering phylogenetic relatedness and were largely consistent with flower morphotypes and associated pollination vectors. Multivariate evolutionary analyses found a positive correlation between the lengths of floral reproductive structures (styles, stigmas, filaments and anthers). Shorter reproductive structures tracked insect-pollinated species and clades in the phylogeny, whereas longer structures tracked wind-pollinated ones, consistent with selective pressures exerted by biotic vs. abiotic pollination vectors, respectively. CONCLUSIONS: Although detectable suites of integrated floral traits across Thalictrum were correlated with wind or insect pollination at the extremes of the morphospace distribution, a presumed intermediate, mixed pollination mode morphospace was also detected. Thus, our data broadly support the existence of detectable flower morphotypes from convergent evolution underlying the evolution of pollination mode in Thalictrum, presumably via different paths from an ancestral mixed pollination state.

  PublisherOA PDFDOI

• A eudicot MIXTA family ancestor likely functioned in both conical cells and trichomes

  Frontiers in Plant Science · 2023-12-18 · 5 citations

  articleOpen accessSenior authorCorresponding

  The MIXTA family of MYB transcription factors modulate the development of diverse epidermal features in land plants. This study investigates the evolutionary history and function of the MIXTA gene family in the early-diverging eudicot model lineage Thalictrum (Ranunculaceae), with R2R3 SBG9-A MYB transcription factors representative of the pre-core eudicot duplication and thus hereby referred to as “paleo MIXTA ” ( PMX ). Cloning and phylogenetic analysis of Thalictrum paleoMIXTA ( ThPMX ) orthologs across 23 species reveal a genus-wide duplication coincident with a whole-genome duplication. Expression analysis by qPCR confirmed that the highest expression is found in carpels, while newly revealing high expression in leaves and nuanced differences between paralogs in representative polyploid species. The single-copy ortholog from the diploid species T. thalictroides ( TthPMX , previously TtMYBML2 ), which has petaloid sepals with conical–papillate cells and trichomes on leaves, was functionally characterized by virus-induced gene silencing (VIGS), and its role in leaves was also assessed from heterologous overexpression in tobacco. Another ortholog from a species with conical–papillate cells on stamen filaments, TclPMX , was also targeted for silencing. Overexpression assays in tobacco provide further evidence that the paleoMIXTA lineage has the potential for leaf trichome function in a core eudicot. Transcriptome analysis by RNA-Seq on leaves of VIGS-treated plants suggests that TthPMX modulates leaf trichome development and morphogenesis through microtubule-associated mechanisms and that this may be a conserved pathway for eudicots. These experiments provide evidence for a combined role for paleoMIXTA orthologs in (leaf) trichomes and (floral) conical–papillate cells that, together with data from other systems, makes the functional reconstruction of a eudicot ancestor most likely as also having a combined function.

  PublisherOA PDFDOI

Recent grants

• RIG: Developmental Genetics of Pollination-Related Floral Phenotypes in Thalictrum

  NSF · $156k · 2008–2011

• Functional Evolution of Flower Organ Identity Genes in the basal Eudicot Thalictrum: Implications for transitions in breeding and pollination systems

  NSF · $553k · 2011–2015

• OPUS: MCS: Evolutionary processes underlying transitions in sexual systems, pollination mode and ploidy

  NSF · $364k · 2019–2024

Frequent coauthors

• Tatiana Arias

  20 shared

• Diego Riaño-Pachón

  Universidade de São Paulo

  15 shared

• Elena M. Kramer

  Harvard University

  9 shared

• Jesús Martínez‐Gómez

  Guardia Civil

  8 shared

• Valerie L. Soza

  University of Washington

  8 shared

• Stephanie J. Conway

  Harvard University

  6 shared

• Kristen D. Hewett Hazelton

  Seattle University

  6 shared

• Gane Ka‐Shu Wong

  University of Alberta

  5 shared

Labs

• Di StilioPI

Education

• B.S., Biology

  University of Buenos Aires (UBA)

• Ph.D., Plant Biology

  University of Massachusetts (Amherst)

• Other, Pollen gene expression and the role of the floral transcription factor SUPERMAN in cell division

  Department of Biochemistry and Molecular Biology, UMass

• Other, Evolution of Development (Evo-Devo)

  Department of Organismic and Evolutionary Biology, Harvard University

Awards & honors

• J. William Fulbright Foreign Scholar, US Dept. of State (201…
• National Geographic Explorer (2019)