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bioRxiv2020

Transcriptional regulation of ZIP genes is independent of local zinc status in Brachypodium shoots upon zinc deficiency and resupply

The biological processes underlying zinc homeostasis are targets for genetic improvement of crops to counter human malnutrition. Detailed phenotyping, ionomic, RNA-Seq analyses and flux measurements with 67Zn isotope revealed whole plant molecular events underlying zinc homeostasis upon varying zinc supply and during zinc resupply to starved Brachypodium distachyon (Brachypodium) plants. Although both zinc deficiency and excess hindered Brachypodium growth, accumulation of biomass and micronutrients into roots and shoots differed depending on zinc supply. The zinc resupply dynamics involved 1893 zinc-responsive genes. Multiple ZIP transporter genes and dozens of other genes were rapidly and transiently down-regulated in early stages of zinc resupply, suggesting a transient zinc shock, sensed locally in roots. Notably genes with identical regulation were observed in shoots without zinc accumulation, pointing to root-to-shoot signals mediating whole plant responses to zinc resupply. Molecular events uncovered in the grass model Brachypodium are useful for the improvement of staple monocots.

plant biology↗

bioRxiv2019

Proposing the solar wind-energy-flux hypothesis as a driver of interannual variation in tropical tree reproductive effort

A growing body of research documents how the El Nino Southern Oscillation (ENSO) results in short-term changes in terrestrial environmental conditions, with the potential to drive ecosystem processes as the duration and severity of ENSO events increases with anthropogenic climate change. An ENSO positive phase results in anomalous patterns of rainfall and temperature throughout the tropics that coincide with leaf flush and increased fruit production in tropical forests worldwide. However, our understanding of possible mechanisms underlying this natural phenomenon is limited. Furthermore, flowering in tropical trees anticipates ENSO development, motivating the continued search for a global phenological cue for tropical angiosperm reproduction. We propose the solar energy flux hypothesis: that a physical energy influx in the Earths upper atmosphere and magnetosphere generated by a positive anomaly in the solar wind preceding ENSO development, cues tropical trees to increase allocation of resources to reproduction. We show that from 1994-2013, the solar wind energy flux into the Earths magnetosphere (Ein) is more strongly correlated with the number of trees in fruit or flower in a Puerto Rican wet forest than the Nino 3.4 climate index, despite Nino 3.4 being a previously identified driver of interannual increases in reproduction. We discuss the idea that changes in the global magnetosphere and thermosphere conditions via solar wind-effects on global atmospheric circulation, principally a weaker Walker circulation, cue interannual increases tropical tree reproduction. This may be a mechanism that synchronizes the reproductive output of the tropical trees to changes in environmental conditions that coincide with ENSO. Thus, space weather patterns may help explain terrestrial biological phenomena that occur at quasi-decadal scales.

plant biology↗

bioRxiv2026

Potential virulence factors in Pyrenophora teres through label-free cellular proteomics analysis

Pyrenophora teres f. teres (Ptt) is the causative agent of net blotch diseases in barley and an economically important pathogen in the barley industry worldwide. To date, however, little is known about the protein expression profile of Ptt, which is important to understand the pathogen behaviour. In this study we report the first cellular proteomics analysis of Ptt. Label-free proteomics was used to quantify the protein expression levels of two parental and one of its progeny isolates from a Ptt cross, grown in culture. One parental isolate of the cross was virulent on the barley variety Prior while the other isolate was avirulent. The progeny isolate used in this study was also virulent on Prior. A total of 3,502 proteins were identified in samples of the three Ptt isolates, of which 99 were found only in the pathogenic isolates, while another 255 proteins were significantly more abundant in the pathogenic isolates compared to the non-pathogenic isolate. Gene ontology analyses of the significant proteins revealed that the proteins increased in pathogenic isolates were involved in fatty acid elongation, biosynthesis of unsaturated fatty acids, glycerophospholipid metabolism, nucleocytoplasmic transport, amino sugar and nucleotide sugar metabolism and metabolic pathways. These protein profiles and the bioinformatic analysis provide new biological information that can be utilised to better understand the pathogenicity of Ptt.

plant biology↗

bioRxiv2023

Control of cell fate specification and patterning by an ancestral microRNA

The formation of an organized body requires the establishment and maintenance of cells with structural and functional distinctive characteristics. A central question in developmental biology is how changes in the regulation of genes drive cell specification and patterning1. microRNAs (miRNAs) are small non-coding RNAs that regulate development through mRNA cleavage and/or translational repression2. In plants, miRNAs regulate key aspects including growth, development, stem cell maintenance, vegetative phase change, leaf morphogenesis, floral organ formation and flowering time3. Biogenesis of plant miRNAs depends on the activity of DICER-LIKE 1 (DCL1), an RNase type III endonuclease that processes double stranded RNA to give rise to mature miRNAs 4. The genomes of todays flora contain at least one bona fide copy of DCL1 5,6. Using Marchantia polymorpha -a model bryophyte that allows comparative approaches to infer characteristics of the ancestral land plant-, we demonstrate that MpDCL1a is required for the biogenesis of miRNAs and uncovered a central role for miR166/Homeodomain Zipper Class III-regulated auxin synthesis in the specification of cell identity, patterning, meristem function, laminar expansion and the development of the body in the last common ancestor of extant land plants.

plant biology↗

bioRxiv2021

Orthogonal control of gene expression in plants using synthetic promoters and CRISPR-based transcription factors

BackgroundThe construction and application of synthetic genetic circuits is frequently improved if gene expression can be orthogonally controlled, relative to the host. In plants, orthogonality can be achieved via the use of CRISPR-based transcription factors that are programmed to act on natural or synthetic promoters. The construction of complex gene circuits can require multiple, orthogonal regulatory interactions, and this in turn requires that the full programmability of CRISPR elements be adapted to non-natural and non-standard promoters that have few constraints on their design. Therefore, we have developed synthetic promoter elements in which regions upstream of the minimal 35S CaMV promoter are designed from scratch to interact via programmed gRNAs with dCas9 fusions that allow activation of gene expression. ResultsA panel of three, mutually orthogonal promoters that can be acted on by artificial gRNAs bound by CRISPR regulators were designed. Guide RNA expression targeting these promoters was in turn controlled by either Pol III (U6) or ethylene-inducible Pol II promoters, implementing for the first time a fully artificial Orthogonal Control System (OCS). Following demonstration of the complete orthogonality of the designs, the OCS was tied to cellular metabolism by putting gRNA expression under the control of an endogenous plant signaling molecule, ethylene. The ability to form complex circuitry was demonstrated via the ethylene-driven, ratiometric expression of fluorescent proteins in single plants. ConclusionsThe design of synthetic promoters is highly generalizable to large tracts of sequence space, allowing Orthogonal Control Systems of increasing complexity to potentially be generated at will. The ability to tie in several different basal features of plant molecular biology (Pol II and Pol III promoters, ethylene regulation) to the OCS demonstrates multiple opportunities for engineering at the system level. Moreover, given the fungibility of the core 35S CaMV promoter elements, the derived synthetic promoters can potentially be utilized across a variety of plant species.

synthetic biology↗

bioRxiv2023

Chromatin compaction and spatial organization in rice interphase nuclei

Chromatin organization and its interactions are essential for biological processes such as DNA repair, transcription, and DNA replication. Detailed cytogenetics data on chromatin conformation, and the arrangement and mutual positioning of chromosome territories in interphase nuclei are still widely missing in plants. In this study, level of chromatin condensation in interphase nuclei of rice (Oryza sativa) and the distribution of chromosome territories (CTs) were analyzed. Super-resolution, stimulated emission depletion (STED), microscopy showed different level of chromatin condensation in leaf and root interphase nuclei. 3D immuno-FISH experiments with painting probes specific to chromosomes 9 and 2 were conducted to investigate their spatial distribution in root and leaf nuclei. Six different configurations of chromosome territories, including their complete association, weak association, and complete separation, were observed in root meristematic nuclei, and four configurations were observed in leaf nuclei. The volume of CTs and frequency of their association varied between the tissue types. The frequency of association of CTs specific to chromosome 9, containing NOR region, is also affected by the activity of the 45S rDNA locus. Our data suggested that the arrangement of chromosomes in the nucleus is connected to the position and the size of the nucleolus. HighlightSuper-resolution STED microscopy uncovered detailed chromatin ultrastructure; high level of differences in chromatin condensation and mutual positioning of chromosome territories between and within leaf and root meristem G1 were observed.

plant biology↗

bioRxiv2023

A high-resolution gene expression atlas of the medial and lateral domains of the gynoecium of Arabidopsis

Angiosperms are characterized by the formation of flowers, and in their inner floral whorl, one or various gynoecia are produced. These female reproductive structures are responsible for fruit and seed production, thus ensuring the reproductive competence of angiosperms. In Arabidopsis thaliana, the gynoecium is composed of two fused carpels with different tissues that need to develop and differentiate to consolidate a mature gynoecium and thus the reproductive competence of Arabidopsis. For these reasons, they have become the object of study for floral and fruit development. However, due to the complexity of the gynoecium, specific spatio-temporal tissues expression patterns are still scarce. In this study, we used precise laser-assisted microdissection and high-throughput RNA sequencing to describe the transcriptional profiles of the medial and lateral domain tissues of the Arabidopsis gynoecium. We provide evidence that the method used is reliable and that, in addition to corroborating gene expression patterns of previously reported regulators of these tissues, we found genes whose expression dynamics point to being involved in cytokinin and auxin homeostasis and in cell cycle progression. Furthermore, based on differential gene expression analyses, we functionally characterized several genes and found that they are involved in gynoecium development. This new resource is available via the Arabidopsis eFP browser and will serve the community in future studies on developmental and reproductive biology.

plant biology↗

bioRxiv2026

Rapid plastid isolation reveals the chloroplast proteome and structures of the chlororibosome large subunit and RuBisCO in Marchantia polymorpha

Plastids house the biology of eukaryotic photosynthesis. While 1000s of plastid genomes have been sequenced, the availability of less than ten proteomes and only two species with full 70S plastid ribosomal structures limit our understanding of plant evolution. We optimized a protocol for the rapid isolation of Marchantia polymorpha plastids that provides a highly enriched and intact organelle fraction from gradient volumes as little as 2 mL. The approach was successfully applied to six other species. Focusing on M. polymorpha, we determined the proteome of the plastid fraction, identifying 1337 nuclear-encoded proteins with a high confidence, where 83% belong to orthologs shared with angiosperms. We further isolated protein complexes by RNA affinity purification using poly-lysine and provide the high-resolution structures of the 50S subunit of the chloroplast ribosome and RuBisCO using cryogenic EM and image reconstruction to 2.23 and 2.12 [A] resolution, respectively. For plastids, our data show that the genome reduction event experienced by the bryophyte common ancestor has had little impact on the organelles complexity and they underscore a high level of structural conservation of key components. Our data provide novel resources to explore the functional evolution of plastid proteomes and major macromolecular complexes of cyanobacterial origin.

plant biology↗

bioRxiv2026

Time-Resolved Phenotyping Reveals Heterogeneous Rice Seed Germination Dynamics in Shallow-Water Culture

Germination percentage is an endpoint measure and therefore does not describe when an individual seed begins visible growth or how rapidly its radicle and plumule expand. We developed a time-resolved phenotyping workflow to quantify rice seed germination continuously in shallow-water culture. A single industrial camera moved along a 1 m rail and imaged three culture boxes at 1 h intervals for up to 80 h. The archive comprised 1,062 full-frame images and 6,372 seed-level repeated observations under the six-seed field-of-view configuration. A physical grid maintained seed identity through time and enabled individual regions of interest to be extracted. Whole-seed foregrounds were obtained with a pretrained U2-Net, and a masked RGB intensity rule separated newly emerging tissue from the darker hull. For each tracked seed, projected emerging-tissue area and interval growth rate were calculated. Three representative normally germinating seeds first showed measurable tissue at 48 h, yet subsequently followed distinct trajectories: final projected areas ranged from 2,605 to 4,700 pixels and peak interval growth rates ranged from 106.88 to 287.92 pixels h-1. B-1 accumulated 63.71% of its final visible area during 72-80 h, whereas B-3 accumulated 73.51% during 60-72 h. Thus, seeds with the same observed emergence interval can differ substantially in the timing and magnitude of post-emergence expansion. The workflow converts repeated images into biologically interpretable temporal phenotypes and provides a basis for nondestructive studies of rice seed vigor and germination heterogeneity.

plant biology↗

bioRxiv2020

Efficiency of biological and chemical inducers for controlling Septoria tritici leaf blotch (STB) on wheat (Triticum aestivum L.)

The hemibiotrophic fungus Zymoseptoria tritici is the causative agent of Septoria tritici leaf blotch (STB) disease of wheat (Triticum aestivum L.), the economically most damaging disease of wheat in Europe. Today, ecofriendly plant protection methods compatible with sustainable agriculture are strongly desirable. Here, we applied the two chemical inducers {beta}-aminobutyric acid (BABA) and benzo-(1,2,3)-thiadiazole-7-carbothioic acid S-methyl ester (BTH) and the two biotic inducers Pseudomonas protegens CHA0 (CHA0) and P. chlororaphis PCL1391 (PCL) on the roots of wheat seedlings in order to test their ability to induce resistance against STB. At 21 days after inoculation, only plants treated with BABA showed a smaller area covered by lesions and less pycnidia compared to the untreated control plants. We evaluated spore germination and fungal development on inoculated wheat leaves at early infection stages using calcofluor white staining. Overall, spores of Z. tritici germinated less on plants soil-drenched with BABA and BTH and their hyphal growth was significantly delayed. On the contrary, CHA0 and PCL seed treatments did not affect fungal growth in wheat leaves. In conclusion, BABA efficiently enhanced plant resistance to Z. tritici, BTH delayed fungal development at early stages while the two biotic inducers did not enhance resistance against STB disease.

plant biology↗

bioRxiv2023

ggPlantmap: an R package for creation of informative and quantitative ggplot maps derived from plant images.

As plant research generates an ever-growing volume of spatial quantitative data, the need for decentralized and user-friendly visualization tools to explore large and complex datasets tools becomes crucial. Existing resources, such as the Plant eFP (electronic Fluorescent Pictograph) browsers, have played a pivotal role on the communication of gene expression data across many plant species. However, although widely used by the plant research community, the Plant eFP browser lacks open and user-friendly tools for the creation of customized expression maps independently. Plant biologists with less coding experience can often encounter challenges when attempting to explore ways to communicate their own spatial quantitative data. We present ggPlantmap an open-source R package designed to address this challenge by providing an easy and user-friendly method for the creation of ggplot representative maps from plant images. ggPlantmap is built in R, one of the most used languages in biology to empower plant scientists to create and customize eFP-like browsers tailored to their experimental data. Here, we provide an overview of the package and tutorials that are accessible even to users with minimal R programming experience. We hope that ggPlantmap can assist the plant science community, fostering innovation and improving our understanding of plant development and function. HighlightggPlantmap, a new addition to the plant data visualization toolbox, allows users to create graphical maps from plant images for the representation of spatial quantitative data in R.

plant biology↗

bioRxiv2023

A protease and a lipoprotein jointly modulate the conserved ExoR-ExoS-ChvI signaling pathway critical in Sinorhizobium meliloti for symbiosis with legume hosts

Sinorhizobium meliloti is a model alpha-proteobacterium for investigating microbe-host interactions, in particular nitrogen-fixing rhizobium-legume symbioses. Successful infection requires complex coordination between compatible host and endosymbiont, including bacterial production of succinoglycan, also known as exopolysaccharide-I (EPS-I). In S. meliloti EPS-I production is controlled by the conserved ExoS-ChvI two-component system. Periplasmic ExoR associates with the ExoS histidine kinase and negatively regulates ChvI-dependent expression of exo genes, necessary for EPS-I synthesis. We show that two extracytoplasmic proteins, LppA (a lipoprotein) and JspA (a metalloprotease), jointly influence EPS-I synthesis by modulating the ExoR-ExoS-ChvI pathway and expression of genes in the ChvI regulon. Deletions of jspA and lppA led to lower EPS-I production and competitive disadvantage during host colonization, for both S. meliloti with Medicago sativa and S. medicae with M. truncatula. Overexpression of jspA reduced steady-state levels of ExoR, suggesting that the JspA protease participates in ExoR degradation. This reduction in ExoR levels is dependent on LppA and can be replicated with ExoR, JspA, and LppA expressed exogenously in Caulobacter crescentus and Escherichia coli. Akin to signaling pathways that sense extracytoplasmic stress in other bacteria, JspA and LppA may monitor periplasmic conditions during interaction with the plant host to adjust accordingly expression of genes that contribute to efficient symbiosis. The molecular mechanisms underlying host colonization in our model system may have parallels in related alpha-proteobacteria. Author summarySymbiotic bacteria that live in the roots of legume plants produce biologically accessible nitrogen compounds, offering a more sustainable and environmentally sound alternative to industrial fertilizers generated from fossil fuels. Understanding the multitude of factors that contribute to successful interaction between such bacteria and their plant hosts can help refine strategies for improving agricultural output. In addition, because disease-causing microbes share many genes with these beneficial bacteria, unraveling the cellular mechanisms that facilitate host invasion can reveal ways to prevent and treat infectious diseases. In this report we show that two genes in the model bacterium Sinorhizobium meliloti contribute to effective symbiosis by helping the cells adapt to living in host plants. This finding furthers knowledge about genetics factors that regulate interactions between microbes and their hosts.

microbiology↗

bioRxiv2020

Gaining comprehensive biological insight into chloroplast RNA editing by performing a broad-spectrum RNA-seq analysis

BackgroundRNA editing is a post-transcriptional modification that complement variation at the DNA level. Until now, different RNA editing systems were found in the major eukaryotic lineages. However, the evolution trajectory in plant chloroplast remains unclear. To gain a better understanding of RNA editing in plant chloroplast, in this study, based on publicly available RNA-seq data across three plant lineages (fern, gymnosperm, and angiosperm), we provided a detailed analysis of RNA editing events in plant chloroplasts and discussed the evolution of RNA editing in land plants. ResultsThere were a total of 5,389 editing sites located in leaf chloroplast identified across 21 plants after rigorous screening. We found that the cluster of RNA editing sites across 21 plants complied with the phylogenetic tree based on linked protein sequences approximately, and majority ([~] 95%) of the editing events resulted in non-synonymous codon changes, RNA editing occurred in second codon position was mainly the largest. Additionally, RNA editing caused an overall increase in hydrophobicity of the resulting proteins. The analyses also revealed that there is an uneven distribution of editing sites among species, genes, and codon positions, the average RNA editing extent varied among different plant species as well as genes. Finally, we found that the loss of editing sites along angiosperm evolution is mainly occurring by reduce of cytosines content, fern plants has the highest cytosine content, with the evolution of plants, cytosine were lost in RNA edited genes. ConclusionsMany of the identified sites in our study have not been previously reported and represent a valuable data set for future research community. Our findings provide valuable information for evolution of RNA editing in plants.

plant biology↗

bioRxiv2021

A CLEM approach to access to the ultrastructure at the graft interface in Arabidopsis thaliana

Despite recent progress in our understanding of the graft union formation, we still know little about the cellular events underlying the grafting process. This is partially due to the difficulty of reliably targeting the graft interface in electron microscopy to study its ultrastructure and three-dimensional architecture. To overcome this technological bottleneck, we developed a correlative light electron microscopy approach (CLEM) to study the graft interface with high ultrastructural resolution. Grafting hypocotyls of Arabidopsis thaliana lines expressing YFP or mRFP in the endoplasmic reticulum allowed the efficient targeting of the grafting interface for under light and electron microscopy. To explore the potential of our method to study sub-cellular events at the graft interface, we focused on the formation of secondary plasmodesmata (PD) between the grafted partners. We showed that 4 classes of PD were formed at the interface and that PD introgression into the call wall was initiated equally by both partners. Moreover, the success of PD formation appeared not systematic with a third of PD not spanning the cell wall entirely. Characterizing the ultrastructural characteristics of these failed PD gives us insights into the process of secondary PD biogenesis. We showed that the thinning of the cell wall and the endoplasmic reticulum-plasma membrane tethering seem to be required for the establishment of symplastic connections between the scion and the rootstock. The resolution reached in this work shows that our CLEM method offer a new scale to the study for biological processes requiring the combination of light and electron microscopy.

plant biology↗

bioRxiv2021

NON-SPECIFIC EFFECTS OF A CINNAMATE-4-HYDROXYLASE INHIBITOR ON AUXIN HOMEOSTASIS

Chemical inhibitors are often implemented for the functional characterization of genes to overcome the limitations associated with genetic approaches. Although being a powerful tool, off-target effects of these inhibitors are easily overlooked in a complex biological setting. Here we illustrate the implications of such secondary effects by focusing on piperonylic acid (PA), an inhibitor of CINNAMATE-4-HYDROXYLASE (C4H) that is often used to investigate the involvement of lignin during plant growth and development. When supplied to plants, we found that PA is recognized as a substrate by GRETCHEN HAGEN 3.6 (GH3.6), an amido synthetase involved in the formation of the auxin catabolite indole-3-acetic acid (IAA)-Asp. By competing for the same enzyme, PA interferes with auxin conjugation, resulting in an increase in cellular auxin concentrations. These increased auxin levels likely further contribute to an increase in adventitious rooting previously observed upon PA-treatment. Despite the focus on GH3.6 in this report, PA is conjugated by an array of enzymes and their subsequent reduced activity on native substrates could potentially affect a whole set of physiological processes in the plant. We conclude that surrogate occupation of the endogenous conjugation machinery in the plant by exogenous compounds is likely a more general phenomenon that is rarely considered in pharmacological studies. Our results hereby provide an important basis for future reference in studies using chemical inhibitors.

plant biology↗

bioRxiv2022

The microtubule-associated protein SlMAP70 interacts with SlIQD21 and regulates fruit shape formation in tomato

The shape of tomato fruits is closely correlated to microtubule organization and the activity of microtubule associated proteins (MAP), but insights into the mechanism from a cell biology perspective are still largely elusive. Analysis of tissue expression profiles of different microtubule regulators revealed that functionally distinct classes of MAPs are highly expressed during fruit development. Among these, several members of the plant-specific MAP70 family are preferably expressed at the initiation stage of fruit development. Transgenic tomato lines overexpressing SlMAP70 produced elongated fruits that show reduced cell circularity and microtubule anisotropy, while SlMAP70 loss-of-function mutant showed an opposite effect with flatter fruits. Microtubule anisotropy of fruit endodermis cells exhibited dramatic rearrangement during tomato fruit development, and SlMAP70-1 is likely implicated in cortical microtubule organization and fruit elongation throughout this stage by interacting with SUN10/SlIQD21a. The expression of SlMAP70 (or co-expression of SlMAP70 and SUN10/SlIQD21a) induces microtubule stabilization and prevents its dynamic rearrangement, both activities are essential for fruit shape establishment after anthesis. Together, our results identify SlMAP70 as a novel regulator of fruit elongation, and demonstrate that manipulating microtubule stability and organization at the early fruit developmental stage has a strong impact on fruit shape.

plant biology↗

bioRxiv2018

A multi-model Framework for the Arabidopsis life cycle

Linking our understanding of biological processes at different scales is a major conceptual challenge in biology, which is aggravated by differences in research methods. Modelling can be a useful approach to consolidating our understanding across traditional research domains. The laboratory model species Arabidopsis thaliana is very widely used to study plant growth processes and has also been tested more recently in eco-physiology and population genetics. However, approaches from crop modelling that might link these domains are rarely applied to Arabidopsis. Here, we combine plant growth models with phenology models from eco-physiology, using the agent-based modelling language Chromar. We introduce a simpler Framework Model of vegetative growth for Arabidopsis, FM-lite. By extending this model to include inflorescence and fruit growth and seed dormancy, we present a whole-life-cycle, multi-model FM-life, which allows us to simulate at the population level in various genotype x environment scenarios. Environmental effects on plant growth distinguish between the simulated life history strategies that were compatible with previously-described Arabidopsis phenology. Our results simulate reproductive success that is founded on the broad range of physiological processes familiar from crop models and suggest an approach to simulate evolution directly in future.\n\nHighlightA whole-life-cycle multi-model for Arabidopsis thaliana combines phenology and physical growth models to explain reproductive success in different genotype x environment scenarios.

plant biology↗

bioRxiv2019

A common molecular basis to the convergent evolution of the selfing syndrome in Capsella

Whether, and to what extent, phenotypic evolution follows predictable genetic paths, remains an important question in evolutionary biology. Convergent evolution of similar characters provides a unique opportunity to address this question. The transition to selfing and the associated changes in flower morphology are among the most prominent examples of repeated evolution in plants. Yet, to date no studies have directly compared the extent of similarities between convergent adaptations to selfing. In this study, we take advantage of the independent transitions to self-fertilization in the genus Capsella to test the existence of genetic and developmental constraints imposed on flower evolution in the context of the selfing syndrome. While C. rubella and C. orientalis have emerged independently, both have evolved almost identical flower characters. Not only the evolutionary outcome is identical but, in both cases, the same developmental strategies underlie the convergent reduction of flower size. This has been associated with convergent evolution of gene-expression changes. The transcriptomic changes common to both selfing lineages are enriched in genes with low-network connectivity and with organ-specific expression patterns. Comparative genetic mapping also indicates that, at least in the case of petal size evolution, these similarities are largely caused by mutations at the same loci. Together, these results suggest that the limited availability of low-pleiotropy paths predetermine closely related species to similar evolutionary outcomes.

plant biology↗