Primeros registros y descripciones genéricas de la familia de holoparásitos aclorófilos Apodanthaceae (Cucurbitales) de Colombia

ABSTRACT: The Apodanthaceae (Cucurbitales) are one of the 12 parasitic clades of flowering plants and the only holoparasitic family with a vegetative phase entirely endophytic, growing primarily on Fabaceae and Salicaceae stems. The two genera of the family, Apodanthes and Pilostyles, are broadly distributed in Colombia, although they remain extremely under-collected and poorly known. Based on feld and herbarium work, and a review of the literature, we provide detailed generic-level descriptions of the family. We also update the records of the family in Colombia and discuss the homology and taxonomic implications of oral characters such as perianth scales, pollen sacs, and the central column. Finally, we provide photographic records of Colombian Apodanthaceae, and some guidelines for properly collecting these plants.RESUMEN: Apodanthaceae (Cucurbitales) es uno de los doce clados de angiospermas parasíticas, y la única familia de especies holoparasíticas con la fase vegetativa completamente endofítica en tallos principalmente de especies de Fabaceae y Salicaceae. Los dos géneros de la familia, Apodanthes y Pilostyles están ampliamente distribuidos en Colombia, aunque han sido muy poco recolectados y permanecen poco conocidos. Con base en trabajo de campo y de herbario, y una extensa revisión bibliográfica, se describen en detalle los caracteres genéricos de la familia. A la vez, se actualizan los registros de la familia en Colombia y se discute la homología e implicaciones taxonómicas de caracteres florales tales como piezas del perianto, sacos polínicos y columna central. Finalmente, presentamos fotografías de las Apodanthaceae colombianas, así como algunas recomendaciones para recolectar adecuadamente estas plantas

Caracteres de la inflorescencia y las flores de las especies colombianas de Tristerix (Loranthaceae) relacionados con la polinización por colibríes

Floral diversification in Loranthaceae reaches its highest peak in the Andes. The flowers of the exclusively Andean genus Tristerix exhibit tubular and vividly coloured flowers pollinated by hummingbirds. We studied inflorescence and flower morphoanatomy of the two Colombian species, T. longebracteatus and the highly endangered T. secundus. Both species have terminal racemes with up to 26 ebracteolate flowers, of which the proximal one opens and sets fruits first. The slightly irregular calyx initiation is followed by the simultaneous initiation of petals and the successive initiation of stamens. Anthesis is fenestrate, explosive, and triggered by the tension of the style against the abaxial petals, a mode so far not reported in Loranthaceae. Anthetic petals spread symmetrically in T. longebracteatus and asymmetrically in T. secundus. Nectar is produced by a supraovarial disk and by the petal mesophyll. Floral lifespan lasts up to 20 days. The hummingbirds Eriocnemis vestita and Pterophanes cyanopterus are the likely pollinators of T. secundus. Morphological traits are inconclusive to support one of the two competing sister group relationships that involve Tristerix, as the lack of cataphylls in renewal shoots links Ligaria and Tristerix, whereas the terminal inflorescences support its relationship with Desmaria and Tupeia.La diversificación floral en Loranthaceae alcanza su máxima expresión en los Andes. Las flores del género Tristerix, restringido exclusivamente a dicha cordillera, exhiben flores tubulares y de color llamativo que son polinizadas por colibríes. Se ha realizado un estudio de la morfoanatomía de inflorescencias y flores en las dos especies colombianas del género, T. longebracteatus y T. secundus, esta última muy amenazada. Las dos especies tienen racimos terminales hasta con 26 flores ebracteoladas, de las cuales la proximal se abre y forma el fruto antes que las demás. La iniciación del cáliz, levemente irregular, es seguida por la iniciación simultánea de los pétalos y la iniciación sucesiva de los estambres. La antesis es fenestrada, explosiva y se activa por la tensión del estilo contra la comisura de los dos pétalos abaxiales, un modo de antesis hasta ahora no descubierta en Loranthaceae. Los pétalos en antesis se expanden simétricamente en T. longebracteatus y asimétricamente en T. secundus. El néctar se produce en un disco supraovárico y el mesófilo de los pétalos. El periodo entre la antesis y la iniciación del fruto dura hasta 20 días. Las especies de colibrí Eriocnemis vestita y Pterophanes cyanopterus son los visitantes y probables polinizadores de T. secundus. Los rasgos morfológicos de Tristerix no aportan información concluyente para apoyar una de las dos hipótesis relacionadas con los posibles grupos hermanos del género, ya que la ausencia de catafilos en los brotes de renuevo asocian Ligaria y Tristerix, en tanto que las inflorescencias terminales apoyan una relación cercana a Desmaria y Tupeia

Sinopsis actualizada de Aristolochia (Aristolochiaceae, Piperales) en Panamá

Background and Aims: The taxonomy of the Panamanian species of Aristolochia is revised 57 years after the first treatment of the genus for the Flora of Panama. The taxonomic, nomenclatural and chorological novelties of the species present in Panama are updated and discussed with respect to the current infrageneric classification.Methods: Specimens of Aristolochia deposited in 35 herbaria, including specimens collected by the senior author. The type specimens available in JSTOR Global Plants were also examined. A key to the infrageneric groups and species (12 of which are illustrated by photographies) is included.Key results: Four of the 13 species reported in the treatment for the Flora of Panama (Aristolochia arborescens, A. costaricensis, A. sylvicolaand A. veraguensis) are currently reduced as synonyms. A total of 16 species are here reported, two of which (A. cruenta and A. trilabiata) are confirmed as new records for Panama. Aristolochia trilabiata, resurrected here to replace A. didyma, is the first report of this species in Mesoamerica. Here we revalidate Aristolochia schippii, A. sprucei and A. surinamensis, recently reduced as synonyms of A. leuconeura, A. constricta and A. trilobata, respectively. In addition, A. pfeiferi and A. translucida are both confirmed as synonyms of A. tonduzii, and A. gorgona and A. securidata as synonyms of A. grandiflora and A. sprucei, respectively. A total of 13 lectotypes are here designated. Finally, the presence of A. constricta, A. gigantea and A. nummularifolia in Panama is discussed.Conclusions: The Panamanian species of Aristolochia belong to two of the three subgenera: A. panamensis, the only species endemic to Panama, marks the southernmost limit of subgenus Siphisia in the New World. The remaining 15 species belong to the subgenus Aristolochia, series Hexandrae (11 spp.) and Thyrsicae (4 spp.).Antecedentes y Objetivos: Se revisa la taxonomía de las especies panameñas de Aristolochia 57 años después del primer tratamiento del género para la Flora de Panamá. Se actualizan y discuten las novedades taxonómicas, nomenclaturales y corológicas de las especies que se encuentran en Panamá con respecto a la clasificación infragenérica actual.Métodos: Se revisaron los ejemplares de Aristolochia en 35 herbarios, incluidas colecciones efectuadas por el autor principal del trabajo. También se consultaron los ejemplares tipo disponibles en JSTOR Global Plants. Se presenta una clave de identificación y una diagnosis de los grupos infragenéricos y de las especies, 12 de las cuales son ilustradas con fotografías.Resultados clave: Cuatro de las 13 especies reportadas para el tratamiento de la Flora de Panamá (Aristolochia arborescens, A. costaricensis, A. sylvicola y A. veraguensis) se encuentran actualmente subordinadas como sinónimos. En total se reportan 16 especies, dos de ellas (A. cruenta y A. trilabiata) confirmadas como nuevos registros para Panamá. Aristolochia trilabiata, revalidado aquí en reemplazo de A. didyma, constituye el primer reporte de la especie en Mesoamérica. Se revalidan A. schippii, A. sprucei y A. surinamensis, recientemente subordinadas a las sinonimias de A. leuconeura, A. constricta y A. trilobata, respectivamente. Además, A. pfeiferi y A. translucida son confirmadas como sinónimos de A. tonduzii, y A. gorgona y A. securidata como sinónimos de A. grandiflora y A. sprucei, respectivamente. Un total de 13 lectotipos son aquí designados. Finalmente, se discute la presencia de A. constricta, A. gigantea y A. nummularifolia en Panamá.Conclusiones: Las especies de Panamá pertenecen a dos de los tres subgéneros de Aristolochia: A. panamensis, la única especie endémica de Panamá, marca el límite más austral del subgénero Siphisia en el Nuevo Mundo. Las 15 especies restantes pertenecen al subgénero Aristolochia, series Hexandrae (11 spp.) y Thyrsicae (4 spp.)

Evolution of the SPATULA/ALCATRAZ gene lineage and expression analyses in the basal eudicot, Bocconia frutescens L. (Papaveraceae)

Abstract Background SPATULA (SPT) and ALCATRAZ (ALC) are recent paralogs that belong to the large bHLH transcription factor family. Orthologs of these genes have been found in all core eudicots, whereas pre-duplication genes, named paleoSPATULA/ALCATRAZ, have been found in basal eudicots, monocots, basal angiosperms and gymnosperms. Nevertheless, functional studies have only been performed in Arabidopsis thaliana, where SPT and ALC are partially redundant in carpel and valve margin development and ALC has a unique role in the dehiscence zone. Further analyses of pre-duplication genes are necessary to assess the functional evolution of this gene lineage. Results We isolated additional paleoSPT/ALC genes from Aristolochia fimbriata, Bocconia frutescens, Cattleya trianae and Hypoxis decumbens from our transcriptome libraries and performed phylogenetic analyses. We identified the previously described bHLH domain in all analyzed sequences and also new conserved motifs using the MEME suite. Finally, we analyzed the expression of three paleoSPT/ALC genes (BofrSPT1/2/3) from Bocconia frutescens, a basal eudicot in the Papaveraceae. To determine the developmental stages at which these genes were expressed, pre- and post-anthesis carpels and fruits of B. frutescens were collected, sectioned, stained, and examined using light microscopy. Using in situ hybridization we detected that BofrSPT1/2/3 genes are expressed in floral buds, early sepal initiation, stamens and carpel primordia and later during fruit development in the dehiscence zone of the opercular fruit. Conclusions Our expression results, in comparison with those available for core eudicots, suggest conserved roles of members of the SPT/ALC gene lineage across eudicots in the specification of carpel margins and the dehiscence zone of the mature fruits. Although there is some redundancy between ALC and SPT, these gene clades seem to have undergone some degree of sub-functionalization in the core eudicots, likely by changes in cis regulatory regions and to some extent in coding sequences, at least in Brassicaceae. Our results also indicate that in Bocconia frutescens, paleoSPT/ALC genes may play a role in early floral organ specification that was subsequently lost in core eudicot lineages

Complete Mitogenomes of Two Aragoa Species and Phylogeny of Plantagineae (Plantaginaceae, Lamiales) Using Mitochondrial Genes and the Nuclear Ribosomal RNA Repeat

Aragoa, comprising 19 high-altitude North Andean species, is one of three genera in the Plantagineae (Plantaginaceae, Lamiales), along with Littorella and Plantago. Based primarily on plastid data and nuclear ITS, Aragoa is sister to a clade of Littorella + Plantago, but Plantagineae relationships have yet to be assessed using multigene datasets from the nuclear and mitochondrial genomes. Here, complete mitogenomes were assembled for two species of Aragoa (A. abietina and A. cleefii). The mitogenomes of both species have a typical suite of genes for 34 proteins, 17 tRNAs, and three rRNAs. The A. abietina mitogenome assembled into a simple circular map, with no large repeats capable of producing alternative isoforms. The A. cleefii mitogenomic map was more complex, involving two circular maps bridged by a substoichiometric linear fragment. Phylogenetics of three mitochondrial genes or the nuclear rRNA repeat placed Aragoa as sister to Littorella + Plantago, consistent with previous studies. However, P. nubicola, the sole representative of subg. Bougueria, was nested within subg. Psyllium based on the mitochondrial and nuclear data, conflicting with plastid-based analyses. Phylogenetics of the nuclear rRNA repeat provided better resolution overall, whereas relationships from mitochondrial data were hindered by extensive substitution rate variation among lineages

Limited mitogenomic degradation in response to a parasitic lifestyle in Orobanchaceae

In parasitic plants, the reduction in plastid genome (plastome) size and content is driven predominantly by the loss of photosynthetic genes. The first completed mitochondrial genomes (mitogenomes) from parasitic mistletoes also exhibit significant degradation, but the generality of this observation for other parasitic plants is unclear. We sequenced the complete mitogenome and plastome of the hemiparasite Castilleja paramensis (Orobanchaceae) and compared them with additional holoparasitic, hemiparasitic and nonparasitic species from Orobanchaceae. Comparative mitogenomic analysis revealed minimal gene loss among the seven Orobanchaceae species, indicating the retention of typical mitochondrial function among Orobanchaceae species. Phylogenetic analysis demonstrated that the mobile cox1 intron was acquired vertically from a nonparasitic ancestor, arguing against a role for Orobanchaceae parasites in the horizontal acquisition or distribution of this intron. The C. paramensis plastome has retained nearly all genes except for the recent pseudogenization of four subunits of the NAD(P)H dehydrogenase complex, indicating a very early stage of plastome degradation. These results lend support to the notion that loss of ndh gene function is the first step of plastome degradation in the transition to a parasitic lifestyle

Limited mitogenomic degradation in response to a parasitic lifestyle in Orobanchaceae

In parasitic plants, the reduction in plastid genome (plastome) size and content is driven predominantly by the loss of photosynthetic genes. The first completed mitochondrial genomes (mitogenomes) from parasitic mistletoes also exhibit significant degradation, but the generality of this observation for other parasitic plants is unclear. We sequenced the complete mitogenome and plastome of the hemiparasite Castilleja paramensis (Orobanchaceae) and compared them with additional holoparasitic, hemiparasitic and nonparasitic species from Orobanchaceae. Comparative mitogenomic analysis revealed minimal gene loss among the seven Orobanchaceae species, indicating the retention of typical mitochondrial function among Orobanchaceae species. Phylogenetic analysis demonstrated that the mobile cox1 intron was acquired vertically from a nonparasitic ancestor, arguing against a role for Orobanchaceae parasites in the horizontal acquisition or distribution of this intron. The C. paramensis plastome has retained nearly all genes except for the recent pseudogenization of four subunits of the NAD(P)H dehydrogenase complex, indicating a very early stage of plastome degradation. These results lend support to the notion that loss of ndh gene function is the first step of plastome degradation in the transition to a parasitic lifestyle

Editorial: Molecular mechanisms of flowering plant reproduction

Plant reproduction is an intricate process important for the survival of all dominant autotrophs and critical in agriculture and stable food production as the basis of our diet. Angiosperms undergo extreme transformations during their ontogeny, leading to the reproductive transition. During this process, several steps are needed, including transforming a shoot apical or a lateral vegetative meristem into an inflorescence meristem with flowering competence. Floral meristems are formed from the latter accompanied by cell differentiation leading to gamete formation in specialized reproductive floral organs. Gamete interaction relies on successful pollination, whether that occurs via biotic or abiotic vectors. In addition, fertilization requires numerous molecular and hormonal signals in place and results in proper pollen tube growth, zygote viability, and seed formation. This Research Topic addresses some of the most outstanding discoveries on angiosperm reproduction in model species like Arabidopsis thaliana and Oryza sativa and crops like cauliflower, cassava, citrus, and sugarcane, among others. In the papers on the topic, the reader will discover highlights on extremely diverse floral promotion pathways, mechanisms of floral organ identity and morphogenesis, sporogenesis and gametogenesis, pollen presentation, pollination, and fertilization strategies.Fil: Pabón Mora, Natalia. Universidad de Antioquia; ColombiaFil: Goldman, Maria Helena S.. Universidade de Sao Paulo; BrasilFil: Smyth, David R.. Monash University; AustraliaFil: Muschietti, Jorge Prometeo. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Investigaciones en Ingeniería Genética y Biología Molecular "Dr. Héctor N. Torres"; ArgentinaFil: Costa, Maria Manuela R.. Universidade do Minho; Portuga

Duplication and Diversification of REPLUMLESS – A Case Study in the Papaveraceae

There is a vast amount of fruit morphological diversity in terms of their texture, the number of carpels, if those carpels are fused or not and how fruits open to disperse the seeds. Arabidopsis thaliana, a model eudicot, has a dry bicarpellate silique, when the fruit matures, the two valves fall apart through the dehiscence zone leaving the seeds attached to the remaining medial tissue, called the replum. Proper replum development in A. thaliana is mediated by REPLUMLESS (RPL), a TALE Homeodomain protein. RPL represses the valve margin genetic program and the downstream dehiscence zone formation in the medial tissue of the siliques and RPL orthologs have conserved roles across the Brassicaceae eudicots. A RPL homolog, qSH1, has been studied in rice, a monocot, and plays a role in fruit shedding making it difficult to predict functional evolution of this gene lineage across angiosperms. Although RPL orthologs have been identified across all angiosperms, expression and functional analyses are scarce. In order to fill the phylogenetic gap between the Brassicaceae and monocots we have characterized the expression patterns of RPL homologs in two poppies with different fruit types, Bocconia frutescens with operculate valvate dehiscence and a persistent medial tissue, similar to a replum, and Papaver somniferum, a poppy with persistent medial tissue in between the multicarpellate gynoecia. We found that RPL homologs in Papaveraceae have broad expression patterns during plant development; in the shoot apical meristem, during flowering transition and in many floral organs, especially the carpels. These patterns are similar to those of RPL in A. thaliana. However, our results suggest that RPL does not have conserved roles in the maintenance of medial persistent tissues of fruits but may be involved with establishing the putative dehiscence zone in dry poppy fruits