Stomatal morphology and physiology explain varied sensitivity to abscisic acid across vascular plant lineages.

Abscisic acid (ABA) can induce rapid stomatal closure in seed plants, but the action of this hormone on the stomata of fern and lycophyte species remains equivocal. Here, ABA-induced stomatal closure, signaling components, guard cell K+ and Ca2+ fluxes, vacuolar and actin cytoskeleton dynamics, and the permeability coefficient of guard cell protoplasts (Pf) were analyzed in species spanning the diversity of vascular land plants including 11 seed plants, 6 ferns, and 1 lycophyte. We found that all 11 seed plants exhibited ABA-induced stomatal closure, but the fern and lycophyte species did not. ABA-induced hydrogen peroxide elevation was observed in all species, but the signaling pathway downstream of nitric oxide production, including ion channel activation, was only observed in seed plants. In the angiosperm faba bean (Vicia faba), ABA application caused large vacuolar compartments to disaggregate, actin filaments to disintegrate into short fragments and Pf to increase. None of these changes was observed in the guard cells of the fern Matteuccia struthiopteris and lycophyte Selaginella moellendorffii treated with ABA, but a hypertonic osmotic solution did induce stomatal closure in fern and the lycophyte. Our results suggest that there is a major difference in the regulation of stomata between the fern and lycophyte plants and the seed plants. Importantly, these findings have uncovered the physiological and biophysical mechanisms that may have been responsible for the evolution of a stomatal response to ABA in the earliest seed plants.

Comparative transcriptome analysis suggests convergent evolution of desiccation tolerance in Selaginella species.

BACKGROUND: Desiccation tolerant Selaginella species evolved to survive extreme environmental conditions. Studies to determine the mechanisms involved in the acquisition of desiccation tolerance (DT) have focused on only a few Selaginella species. Due to the large diversity in morphology and the wide range of responses to desiccation within the genus, the understanding of the molecular basis of DT in Selaginella species is still limited. RESULTS: Here we present a reference transcriptome for the desiccation tolerant species S. sellowii and the desiccation sensitive species S. denticulata. The analysis also included transcriptome data for the well-studied S. lepidophylla (desiccation tolerant), in order to identify DT mechanisms that are independent of morphological adaptations. We used a comparative approach to discriminate between DT responses and the common water loss response in Selaginella species. Predicted proteomes show strong homology, but most of the desiccation responsive genes differ between species. Despite such differences, functional analysis revealed that tolerant species with different morphologies employ similar mechanisms to survive desiccation. Significant functions involved in DT and shared by both tolerant species included induction of antioxidant systems, amino acid and secondary metabolism, whereas species-specific responses included cell wall modification and carbohydrate metabolism. CONCLUSIONS: Reference transcriptomes generated in this work represent a valuable resource to study Selaginella biology and plant evolution in relation to DT. Our results provide evidence of convergent evolution of S. sellowii and S. lepidophylla due to the different gene sets that underwent selection to acquire DT.

An update and reassessment of fern and lycophyte diversity data in the Japanese Archipelago.

The fern and lycophyte flora of Japan comprising 721 native taxa (including subspecies and varieties) plus 371 interspecific hybrids was reassessed using a nearly comprehensively sampled distribution map at 10 km resolution vouchered by 216,687 specimens, up-to-date cytotaxonomic information covering 74% of the taxa, and an rbcL sequence dataset covering 97.9% of the taxa. Spatial distribution of species richness and phylogenetic diversity was visualized. Apomixis was observed in 11.0% of the native taxa whose reproductive modes are known. The number of sexually reproducing polyploid taxa (n = 199) is less than sexual diploids (n = 241), and 30 of them are evidently allopolyploid, in contrast with the low number of possible autopolyploids (n = 4). Apomictic taxa were found to have smaller latitudinal ranges than sexual taxa or taxa with multiple reproductive modes. A morphological character dataset in Lucid format is provided for taxonomic identification of the native taxa.

Virtual issue: Ecology and evolution of pteridophytes in the era of molecular genetics.

The past quarter-century has witnessed a revolution in our understanding of the phylogenetics, systematics, and ecology of pteridophytes (ferns and lycophytes), particularly due to the rapid accumulation of plastid sequence data and a renewed interest in the ecology of the sexual phase of the life cycle. We here compile 19 papers recently published in the Journal of Plant Research dealing with the biology of pteridophytes, grouped into six categories: (1) breeding systems, (2) species complexes and polyploidization, (3) fossil taxa, (4) gametophyte ecology, (5) systematics, (6) biodiversity. We hope this collection of papers will be of value to researchers interested in this fascinating group of plants.

Molecular characterization of the 14-3-3 gene family in rice and its expression studies under abiotic stress.

MAIN CONCLUSION: 14-3-3 isoforms were relatively less conserved at the C-terminal region across plant groups. Both Os 14-3-3f and Os 14-3-3g were inducible with differential gene expression levels under different abiotic stress and developmental stages in sensitive and tolerant indica rice cultivars as confirmed both at transcript and protein level. Plant 14-3-3s has been well characterized to function in several signaling pathways, biotic as well as abiotic stress and nutrient metabolism. We attempted comprehensive analysis of 14-3-3 genes in different plant lineages such as green algae (Chlamydomonas reinhardtii), moss (Physcomitrella patens) and lycophyte (Selaginella moellendorffii), dicot Arabidopsis thaliana and monocot Oryza sativa sub sp. japonica at the gene and protein level. Sequence alignment results revealed that 14-3-3 isoforms were evolutionarily conserved across all taxa with variable C-terminal end. Phylogenetic analysis indicated that the majority of 14-3-3 isoforms in rice belong to the non-epsilon group that clustered separately from the dicot group. Segmental duplication event played a significant role in the expansion of both, Arabidopsis and rice, 14-3-3 isoforms as revealed by synteny studies. In silico gene expression using Massive Parallel Signature Sequencing and microarray analysis revealed that 14-3-3 isoforms have variable expression in different tissue types and under different abiotic stress regime in Arabidopsis and japonica rice. Both, semi-quantitative and qPCR results, confirmed that Os14-3-3f and Os14-3-3g were inducible under abiotic stress in lamina and roots of indica rice and relatively higher under salinity and cold stress in Nonabokra, under dehydration stress in N-22 and under exogenous ABA in IR-29 usually after 3-6 h of treatment. Both, 14-3-3f and 14-3-3g, were highly expressed in flag leaves, stems and panicles and mature roots. These results were further confirmed by immunoblot analysis of rice cultivars using Os14-3-3f antibody generated from recombinant Os14-3-3f protein. The results provide the first comprehensive report of Os14-3-3 gene expression in indica rice cultivars which differ in tolerance to abiotic stress that might be useful for further research.

Adaptive responses of mature giant chloroplasts in the deep-shade lycopod Selaginella erythropus to prolonged light and dark periods.

Deep-shade plants have adapted to low-light conditions by varying morphology and physiology of cells and chloroplasts, but it still remains unclear, if prolonged periods of high-light or darkness induce additional modifications in chloroplasts' anatomy and pigment patterns. We studied giant chloroplasts (bizonoplasts) of the deep-shade lycopod Selaginella erythropus in epidermal cells of mature fully developed microphylls and subjected them to prolonged darkness and high-light conditions. Chloroplast size and ultrastructure were investigated by light and electron microscopy. Physiological traits were studied by pigment analyses, photosynthetic performance of photosystem II, and formation of reactive oxygen species. Results show that (a) thylakoid patterns and shape of mature bizonoplasts vary in response to light and dark conditions. (b) Prolonged darkness induces transitory formation of prolamellar bodies, which so far have not been described in mature chloroplasts. (c) Photosynthetic activity is linked to structural responses of chloroplasts. (d) Photosystem II is less active in the upper zone of bizonoplasts and more efficient in the grana region. (e) Formation of reactive oxygen species reflects the stress level caused by high-light. We conclude that during prolonged darkness, chlorophyll persists and even increases; prolamellar bodies form de novo in mature chloroplasts; bizonoplasts have spatial heterogeneity of photosynthetic performance.

The enigma of sex allocation in Selaginella.

Background and Aims: The division of resource investment between male and female functions is poorly known for land plants other than angiosperms. The ancient lycophyte genus Selaginella is similar in some ways to angiosperms (in heterospory and in having sex allocation occur in the sporophyte generation, for example) but lacks the post-fertilization maternal investments that angiosperms make via fruit and seed tissues. One would therefore expect Selaginella to have sex allocation values less female-biased than in flowering plants and closer to the theoretical prediction of equal investment in male and female functions. Nothing is currently known of sex allocation in the genus, so even the simplest predictions have not been tested. Methods: Volumetric measurements of microsporangial and megasporangial investment were made in 14 species of Selaginella from four continents. In five of these species the length of the main above-ground axis of each plant was measured to determine whether sex allocation is related to plant size. Key Results: Of the 14 species, 13 showed male-biased allocations, often extreme, in population means and among the great majority of individual plants. There was some indication from the five species with axis length measurements that relative male allocation might be related to the release height of spores, but this evidence is preliminary. Conclusions: Sex allocation in Selaginella provides a phylogenetic touchstone showing how the innovations of fruit and seed investment in the angiosperm life cycle lead to typically female-biased allocations in that lineage. Moreover, the male bias we found in Selaginella requires an evolutionary explanation. The bias was often greater than what would occur from the mere absence of seed and fruit investments, and thus poses a challenge to sex allocation theory. It is possible that differences between microspores and megaspores in their dispersal ecology create selective effects that favour male-biased sexual allocation. This hypothesis remains tentative.

Light acclimation in the lycophyte Selaginella martensii depends on changes in the amount of photosystems and on the flexibility of the light-harvesting complex II antenna association with both photosystems.

Vascular plants have evolved a long-term light acclimation strategy primarily relying on the regulation of the relative amounts of light-harvesting complex II (LHCII) and of the two photosystems, photosystem I (PSI) and photosystem II (PSII). We investigated whether such a model is also valid in Selaginella martensii, a species belonging to the early diverging group of lycophytes. Selaginella martensii plants were acclimated to three natural light regimes (extremely low light (L), medium light (M) and full sunlight (H)) and thylakoid organization was characterized combining ultrastructural, biochemical and functional methods. From L to H plants, thylakoid architecture was rearranged from (pseudo)lamellar to predominantly granal, the PSII : PSI ratio changed in favour of PSI, and the photochemical capacity increased. However, regulation of light harvesting did not occur through variations in the amount of free LHCII, but rather resulted from the flexibility of the association of free LHCII with PSII and PSI. In lycophytes, the free interspersed LHCII serves a fixed proportion of reaction centres, either PSII or PSI, and the regulation of PSI-LHCII(-PSII) megacomplexes is an integral part of long-term acclimation. Free LHCII ensures photoprotection of PSII, allows regulated use of PSI as an energy quencher, and can also quench endangered PSI.

Fern and lycophyte guard cells do not respond to endogenous abscisic acid.

Stomatal guard cells regulate plant photosynthesis and transpiration. Central to the control of seed plant stomatal movement is the phytohormone abscisic acid (ABA); however, differences in the sensitivity of guard cells to this ubiquitous chemical have been reported across land plant lineages. Using a phylogenetic approach to investigate guard cell control, we examined the diversity of stomatal responses to endogenous ABA and leaf water potential during water stress. We show that although all species respond similarly to leaf water deficit in terms of enhanced levels of ABA and closed stomata, the function of fern and lycophyte stomata diverged strongly from seed plant species upon rehydration. When instantaneously rehydrated from a water-stressed state, fern and lycophyte stomata rapidly reopened to predrought levels despite the high levels of endogenous ABA in the leaf. In seed plants under the same conditions, high levels of ABA in the leaf prevented rapid reopening of stomata. We conclude that endogenous ABA synthesized by ferns and lycophytes plays little role in the regulation of transpiration, with stomata passively responsive to leaf water potential. These results support a gradualistic model of stomatal control evolution, offering opportunities for molecular and guard cell biochemical studies to gain further insights into stomatal control.

Ultrastructural organization of the thylakoid system during the afternoon relocation of the giant chloroplast in Selaginella martensii Spring (Lycopodiophyta).

Within the ancient vascular plant lineage known as lycophytes, many Selaginella species contain only one giant chloroplast in the upper epidermal cells of the leaf. In deep-shade species, such as S. martensii, the chloroplast is cup-shaped and the thylakoid system differentiates into an upper lamellar region and a lower granal region (bizonoplast). In this report, we describe the ultrastructural changes occurring in the giant chloroplast hosted in the epidermal cells of S. martensii during the daily relocation of the organelle. The process occurs in up to ca. 40% of the microphylls without the plants being exposed to high-light flecks. The relocated chloroplast loses its cup shape: first, it flattens laterally toward the radial cell wall and then assumes a more globular shape. The loss of the conical cell shape, the side-by-side lateral positioning of vacuole and chloroplast, and the extensive rearrangement of the thylakoid system to only granal cooperate in limiting light absorption. While the cup-shaped chloroplast emphasizes the light-harvesting capacity in the morning, the relocated chloroplast is suggested to support the renewal of the thylakoid system during the afternoon, including the recovery of photosystem II (PSII) from photoinhibition. The giant chloroplast repositioning is part of a complex reversible reshaping of the whole epidermal cell.

A total evidence approach to understanding phylogenetic relationships and ecological diversity in Selaginella subg. Tetragonostachys.

PREMISE OF THE STUDY: Several members of Selaginella are renowned for their ability to survive extreme drought and "resurrect" when conditions improve. Many of these belong to subgenus Tetragonostachys, a group of ∼45 species primarily found in North and Central America, with substantial diversity in the Sonoran and Chihuahuan Deserts. We evaluated the monophyly and the age of subgenus Tetragonostachys and assess how drought tolerance contributed to the evolution of this clade. METHODS: Our study included most Tetragonostachys species, using plastid and nuclear sequences, fossil and herbarium records, and climate variables to describe the species diversity, phylogenetic relationships, divergence times, and climatic niche evolution in the subgenus. KEY RESULTS: We found that subgenus Tetragonostachys forms a monophyletic group sister to Selaginella lepidophylla and may have diverged from other Selaginella because of a Gondwanan-Laurasian vicariance event ca. 240 mya. The North American radiation of Tetragonostachys appears to be much more recent and to have occurred during the Early Cretaceous-late Paleocene interval. We identified two significant and nested ecological niche shifts during the evolution of Tetragonostachys associated with extreme drought tolerance and a more recent shift to cold climates. Our analyses suggest that drought tolerance evolved in the warm deserts of southwest North America and may have been advantageous for colonization of cold and dry boreal climates. CONCLUSIONS: Our investigation provides a foundation for future research addressing the genomics of ecological niche evolution and the potential role of reticulate evolution in Selaginella subgenus Tetragonostachys.

Increased photosynthesis from a deep-shade to high-light regime occurs by enhanced CO2 diffusion into the leaf of Selaginella martensii.

The current understanding of photosynthesis across land plant phylogeny strongly indicates that ancient vascular plants are mainly limited by strong constitutive CO2 diffusional constraints, particularly low stomatal and mesophyll conductance. Considering that the lycophyte Selaginella martensii can demonstrate long-term light acclimation, this study addresses the regulation extent of CO2 assimilation in this species cultivated under contrasting light regimes of deep shade, medium shade and high light. Comparative analyses of photosynthetic traits, CO2 conductance and leaf morpho-anatomy revealed acclimation plasticity similar to that of seed plants, though occurring in the context of an inherently low photosynthetic capacity typical of lycophytes. Specific modulations of the stomatal density and aperture, chloroplast surface exposed to mesophyll airspaces and cell wall thickness sustained a marked improvement in CO2 diffusion from deep shade to high light. However, the maximum carboxylation rate was comparatively less effectively upregulated, leading to a greater incidence of biochemical limitations of photosynthesis. Because of a low carboxylation capacity under any light regime, a lycophyte prevents potential photodamage to the chloroplast by not only exploiting the thermal dissipation of excess absorbed energy but also diverting a large fraction of photosynthetic electrons to sinks alternative to carboxylation.

Nano-indentation reveals a potential role for gradients of cell wall stiffness in directional movement of the resurrection plant Selaginella lepidophylla.

As a physical response to water loss during drought, inner Selaginella lepidophylla stems curl into a spiral shape to prevent photoirradiation damage to their photosynthetic surfaces. Curling is reversible and involves hierarchical deformation, making S. lepidophylla an attractive model with which to study water-responsive actuation. Investigation at the organ and tissue level has led to the understanding that the direction and extent of stem curling can be partially attributed to stiffness gradients between adaxial and abaxial stem sides at the nanoscale. Here, we examine cell wall elasticity to understand how it contributes to the overall stem curling. We compare the measured elastic moduli along the stem length and between adaxial and abaxial stem sides using atomic force microscopy nano-indentation testing. We show that changes in cortex secondary cell wall development lead to cell wall stiffness gradients from stem tip to base, and also between adaxial and abaxial stem sides. Changes in cortical cell wall morphology and secondary cell wall composition are suggested to contribute to the observed stiffness gradients.

Characterization of chloroplast iridescence in Selaginella erythropus.

Iridescence in shade-dwelling plants has previously been described in only a few plant groups, and even fewer where the structural colour is produced by intracellular structures. In contrast with other Selaginella species, this work reports the first example in the genus of structural colour originating from modified chloroplasts. Characterization of these structures determines that they form one-dimensional photonic multilayers. The Selaginella bizonoplasts present an analogous structure to recently reported Begonia iridoplasts; however, unlike Begonia species that produce iridoplasts, this Selaginella species was not previously described as iridescent. This therefore raises the possibility of widespread but unobserved and uncharacterized photonic structures in plants.

Genome Analysis of the Ancient Tracheophyte Selaginella tamariscina Reveals Evolutionary Features Relevant to the Acquisition of Desiccation Tolerance.

Resurrection plants, which are the "gifts" of natural evolution, are ideal models for studying the genetic basis of plant desiccation tolerance. Here, we report a high-quality genome assembly of 301 Mb for the diploid spike moss Selaginella tamariscina, a primitive vascular resurrection plant. We predicated 27 761 protein-coding genes from the assembled S. tamariscina genome, 11.38% (2363) of which showed significant expression changes in response to desiccation. Approximately 60.58% of the S. tamariscina genome was annotated as repetitive DNA, which is an almost 2-fold increase of that in the genome of desiccation-sensitive Selaginella moellendorffii. Genomic and transcriptomic analyses highlight the unique evolution and complex regulations of the desiccation response in S. tamariscina, including species-specific expansion of the oleosin and pentatricopeptide repeat gene families, unique genes and pathways for reactive oxygen species generation and scavenging, and enhanced abscisic acid (ABA) biosynthesis and potentially distinct regulation of ABA signaling and response. Comparative analysis of chloroplast genomes of several Selaginella species revealed a unique structural rearrangement and the complete loss of chloroplast NAD(P)H dehydrogenase (NDH) genes in S. tamariscina, suggesting a link between the absence of the NDH complex and desiccation tolerance. Taken together, our comparative genomic and transcriptomic analyses reveal common and species-specific desiccation tolerance strategies in S. tamariscina, providing significant insights into the desiccation tolerance mechanism and the evolution of resurrection plants.

The adaptive value of heterospory: Evidence from Selaginella.

Heterospory was a pivotal evolutionary innovation for land plants, but it has never been clear why it evolved. We used the geographic distributions of 114 species of the heterosporous lycophyte Selaginella to explore the functional ecology of microspore and megaspore size, traits that would be correlated with many aspects of a species' regeneration niche. We characterized habitats at a global scale using leaf area index (LAI), a measure of foliage density and thus shading, and net primary productivity (NPP), a measure of growth potential. Microspore size tends to decrease as habitat LAI and NPP increase, a trend that could be related to desiccation resistance or to filtration of wind-borne particles by leaf surfaces. Megaspore size tends to increase among species that inhabit regions of high LAI, but there is an important interaction with NPP. This geographical pattern suggests that larger megaspores provide an establishment advantage in shaded habitats, although in open habitats, where light is less limiting, higher productivity of the environment seems to give an advantage to species with smaller megaspores. These results support previous theoretical arguments that heterospory was originally an adaptation to the increasing height and density of Devonian vegetative canopies that accompanied the diversification of vascular plants with leaves.

Metabolomic profiling in Selaginella lepidophylla at various hydration states provides new insights into the mechanistic basis of desiccation tolerance.

Selaginella lepidophylla is one of only a few species of spike mosses (Selaginellaceae) that have evolved desiccation tolerance (DT) or the ability to 'resurrect' from an air-dried state. In order to understand the metabolic basis of DT, S. lepidophylla was subjected to a five-stage, rehydration/dehydration cycle, then analyzed using non-biased, global metabolomics profiling technology based on GC/MS and UHLC/MS/MS(2) platforms. A total of 251 metabolites including 167 named (66.5%) and 84 (33.4%) unnamed compounds were characterized. Only 42 (16.7%) and 74 (29.5%) of compounds showed significantly increased or decreased abundance, respectively, indicating that most compounds were produced constitutively, including highly abundant trehalose, sucrose, and glucose. Several glycolysis/gluconeogenesis and tricarboxylic acid (TCA) cycle intermediates showed increased abundance at 100% relative water content (RWC) and 50% RWC. Vanillate, a potent antioxidant, was also more abundant in the hydrated state. Many different sugar alcohols and sugar acids were more abundant in the hydrated state. These polyols likely decelerate the rate of water loss during the drying process as well as slow water absorption during rehydration, stabilize proteins, and scavenge reactive oxygen species (ROS). In contrast, nitrogen-rich and γ-glutamyl amino acids, citrulline, and nucleotide catabolism products (e.g. allantoin) were more abundant in the dry states, suggesting that these compounds might play important roles in nitrogen remobilization during rehydration or in ROS scavenging. UV-protective compounds such as 3-(3-hydroxyphenyl)propionate, apigenin, and naringenin, were more abundant in the dry states. Most lipids were produced constitutively, with the exception of choline phosphate, which was more abundant in dry states and likely plays a role in membrane hydration and stabilization. In contrast, several polyunsaturated fatty acids were more abundant in the hydrated states, suggesting that these compounds likely help maintain membrane fluidity during dehydration. Lastly, S. lepidophylla contained seven unnamed compounds that displayed twofold or greater abundance in dry or rehydrating states, suggesting that these compounds might play adaptive roles in DT.

Physiological framework for adaptation of stomata to CO2 from glacial to future concentrations.

In response to short-term fluctuations in atmospheric CO(2) concentration, c(a), plants adjust leaf diffusive conductance to CO(2), g(c), via feedback regulation of stomatal aperture as part of a mechanism for optimizing CO(2) uptake with respect to water loss. The operational range of this elaborate control mechanism is determined by the maximum diffusive conductance to CO(2), g(c(max)), which is set by the size (S) and density (number per unit area, D) of stomata on the leaf surface. Here, we show that, in response to long-term exposure to elevated or subambient c(a), plants alter g(c(max)) in the direction of the short-term feedback response of g(c) to c(a) via adjustment of S and D. This adaptive feedback response to c(a), consistent with long-term optimization of leaf gas exchange, was observed in four species spanning a diverse taxonomic range (the lycophyte Selaginella uncinata, the fern Osmunda regalis and the angiosperms Commelina communis and Vicia faba). Furthermore, using direct observation as well as flow cytometry, we observed correlated increases in S, guard cell nucleus size and average apparent 1C DNA amount in epidermal cell nuclei with increasing c(a), suggesting that stomatal and leaf adaptation to c(a) is linked to genome scaling.

Photosynthetic characteristics and the response of stomata to environmental determinants and ABA in Selaginella bryopteris, a resurrection spike moss species.

Selaginella bryopteris is a spike-moss lycophyte species with resurrection capability. These plants have small sized stomata that occur in higher density than in other fern species. The diurnal gas-exchange studies under natural conditions showed a bell shaped net photosynthesis curve. The effective quantum yield of PSII (ΔF/F(m')) showed an inverse relationship with light and recovered to its maximum at sunset. This suggests that there was a complete recovery of PSII efficiency during the late evening hours. S. bryopteris displayed broad temperature optima for net photosynthesis from 28 °C to 37 °C. The stomatal sensitivity in response to vapor pressure deficit (VPD), was maximum at 25 °C temperature while at temperatures from 30 to 35 °C it was low. Our study demonstrates that S. bryopteris plants show a very poor mechanism for its stomatal regulation in response to high light, high temperature, high VPD, high CO2 and to ABA treatment. At the same time they show a high stomatal conductance leading to unrestricted rates of transpiration and a lack of capacity to optimize water use efficiency (WUE).

Chapter 4. New model systems for the study of developmental evolution in plants.

The number of genetically tractable plant model systems is rapidly increasing, thanks to the decreasing cost of sequencing and the wide amenability of plants to stable transformation and other functional approaches. In this chapter, I discuss emerging model systems from throughout the land plant phylogeny and consider how their unique attributes are contributing to our understanding of development, evolution, and ecology. These new models are being developed using two distinct strategies: in some cases, they are selected because of their close relationship to the established models, while in others, they are chosen with the explicit intention of exploring distantly related plant lineages. Such complementary approaches are yielding exciting new results that shed light on both micro- and macroevolutionary processes in the context of developmental evolution.