Plant Systematics and Evolution最新文献

Abstract

Vriesea is one of the most diverse genera in the Brazilian Atlantic Forest, comprising approximately 170 species in this domain. Included in this genus, the V. ensiformis group encompasses ten species that are distributed from northeastern to southern Brazil. During field expeditions in Parque Nacional da Serra dos Órgãos, Rio de Janeiro, Brazil, we found a new species which was previously long recognized as Vriesea aff. gradata in herbaria. Thus, here we aim to describe V. organensis and investigate its phylogenetic relationship to other species in the V. ensiformis group through a total evidence approach. We conducted an extensive literature review, herbarium consulting and field trips to gather data for describing the new species. Additionally, we constructed a concatenated matrix of molecular and morphological data to generate a phylogenetic hypothesis for the V. ensiformis group. Vriesea organensis is morphologically related to V. psittacina, V. gradata and V. fluviatilis and is described as possibly critically endangered. Our phylogenetic tree revealed that V. organensis is closely related to V. fluviatilis, in contrast to the herbarium hypothesis of similarity with V. gradata. The new species is characterized by the floral bracts incurvate and strongly carinate at the apex, rachis exposed when flowering, petal yellow with green apex and stigma exceeding the anthers. Furthermore, our findings indicate that the V. ensiformis group is not monophyletic based on our dataset.

The aquatic and wetland plant genus Bacopa contains species that are found worldwide, with a center of diversity in the Americas. Although there have been regional taxonomic studies of the genus, a global synthesis is lacking. Variation in morphological features across species has complicated efforts to determine species boundaries and circumscribe infrageneric categories with confidence. Molecular data have enabled a more thorough understanding of phylogenetic relationships in Bacopa, and these can be used to develop a more stable taxonomy for the genus. Because there are approximately 60 species in the genus, it would be helpful to have a phylogenetically informed sectional classification and an improved understanding of ancestral biogeography and morphological evolution. We obtained novel molecular data for 28 species and produced phylogenetic hypotheses that include most species in the genus. The phylogenetic evidence supports at least four independent transitions to becoming fully aquatic species. We also reconstructed three separate ancestral dispersal events into Africa and beyond. Morphometric data were used to evaluate species boundaries and synonymy. We update sectional circumscriptions and propose a new section, Bacopa sect. Conobea, to accommodate species formerly in the genus Conobea that were found to be monophyletic with Bacopa.

The Liliaceae family includes the perennial, herbaceous, monocotyledonous plant Lilium candidum (L. candidum). The cosmetics, fragrance, and pharmaceutical industries regularly use L. candidum. It has been widely used in traditional medicine for wound healing, and its anti-inflammatory, antidiabetic, antimicrobial, and anticancer effects have been demonstrated in various studies. Natural populations of L. candidum are significantly affected by biotic and abiotic factors such as anthropological pressure, diseases, pathogen attacks, fossil fuel pollution, and climate change. Overcollection and destruction of its habitat put L. candidum into the endangered category. Therefore, it is of great importance to preserve this plant's genetic diversity, which plays a crucial role in adapting to different conditions, preserving evolutionary potential, and breeding studies. Molecular markers are essential in breeding and evolution studies to conserve genetic resources. Because of its economic and medical importance, various DNA markers have been used to evaluate the genetic diversity of L. candidum accessions. In this study, the genetic diversity of L. candidum, which is native to Türkiye, was determined with ISSR and SSR molecular markers among accessions collected from seven different cities and 76 accessions (Muğla, İzmir, Aydın, Antalya, Balıkesir, Denizli, and Manisa). Genetic distances and phylogenetic analysis were carried out using the software TASSEL 5.2.63. The assessment of genetic diversity was visualized through a UPGMA dendrogram. The resulting phylogenetic tree revealed two distinct groups. The closest and farthest accessions were determined according to the genetic distance matrix. It was determined that the highest genetic distance value was between 19 (Balıkesir, Kepsut) and 76 (Muğla, Ula) accessions (0.5390946) and the lowest genetic distance value was between 53 (Muğla, Marmaris) and 54 (Muğla, Marmaris) accessions (0.1069968).

Abstract

Laurus (Lauraceae) species are currently restricted to isolated refugia in the southern Black Sea, Mediterranean Basin, southern Morocco, and Macaronesian archipelagos. One to three species of Laurus has been recognized: the Azorean endemic Laurus azorica, L. nobilis from the Mediterranean, and L. novocanariensis from Madeira and the Canary Islands. This study aims to determine the population structure, genetic diversity, and associated patterns of gene flow within and between Azorean populations, using eight existing SSR markers. We also included plant material from L. nobilis populations found in the Azores, for comparison. Amplification was performed in 212 samples of L. azorica and in 30 samples of L. nobilis. For L. azorica, 78 alleles were amplified (average 9.75 alleles per loci). Bayesian analysis with STRUCTURE unveiled five genetic groups for the Azorean accessions, with high level of genetic admixture. Genetic diversity was generally high, with moderate levels of genetic differentiation among L. azorica populations. Moreover, high gene flow levels, likely mediated by past human translocations and naturally, by birds, might have contributed to the high level of genetic admixture observed possibly reflecting hybridization events between L. nobilis and L. azorica. Conservation measures should be applied to some populations of São Miguel, Santa Maria, and Flores Islands, based on the number of private alleles, and further, ad hoc translocation events should be avoided. Conservation in situ and the preservation of laurel forest remains are recommended. The study of this species’ taxonomy, genetics, and population dynamics in the Macaronesian region should be continued.

The cashew tree Anacardium occidentale is a globally important food species and in Brazil is a natural component of cerrado and restinga vegetation and has an important role in local economies as a food and medicinal plant. Nevertheless, diversity studies of wild populations—the most important reservoir of natural variation—of this naturally widespread species are urgently needed for conservation strategies because of human impact on tropical American ecosystems where it occurs. Here, we sought to differentiate the previously recognized restinga and cerrado ecotypes using multivariate morphometrics of wild populations in a limited area of northeast Brazil (northern Piauí and northeastern Maranhão states). Thirty individuals were sampled for 47 vegetative and reproductive descriptors from six wild populations (three of each ecotype). Data analysis included principal component analysis and three classification methods (linear discriminant analysis, k-nearest neighbour analysis and classification and regression tree analysis); cross-validation tests were applied to classification results. Univariate statistics obtained for each population and ecotype were found to be consistent with the previously proposed distinction between the two ecotypes. Although principal component analysis showed extensive variation and overlap between populations, cross-validations of classification analyses showed strong differentiation between ecotypes and between most populations; vegetative and reproductive variables were equally important for discrimination. Cerrado populations were more variable and somewhat less distinct than restinga ones. New molecular genetic investigations of wild populations are needed to provide genetic support for the morphological differentiation of the ecotypes reported here.

Connaraceae is a pantropical family of about 200 species containing lianas and small trees with remarkably diverse floral polymorphisms, including distyly, tristyly, homostyly, and dioecy. To date, relationships within the family have not been investigated using a targeted molecular phylogenetic treatment, severely limiting systematic understanding and reconstruction of trait evolution. Accordingly, their last infrafamilial classification was based only on morphological data. Here, we used phylogenomic data obtained using the Angiosperms353 nuclear target sequence capture probes, sampling all tribes and almost all genera, entirely from herbarium specimens, to revise infrafamilial classification and investigate the evolution of heterostyly. The backbone of the resulting molecular phylogenetic tree is almost entirely resolved. Connaraceae consists of two clades, one containing only the African genus Manotes (4 or 5 species), which we newly recognize at the subfamily level. Vegetative and reproductive synapomorphies are proposed for Manotoideae. Within Connaroideae, Connareae is expanded to include the former Jollydoreae. The backbone of Cnestideae, which contains more than half of the Connaraceae species, remains incompletely resolved. Reconstructions of reproductive system evolution are presented that tentatively support tristyly as the ancestral state for the family, with multiple parallel losses, in agreement with previous hypotheses, plus possible re-gains. However, the great diversity of stylar polymorphisms and their phylogenetic lability preclude a definitive answer. Overall, this study reinforces the usefulness of herbarium phylogenomics, and unlocks the reproductive diversity of Connaraceae as a model system for the evolution of complex biological phenomena.

Supplementary information: The online version contains supplementary material available at 10.1007/s00606-024-01909-y.

The availability of genome sequence resources and genomic information enables the functional characterization of genes in crop plants. These genes can be used in targeted crop breeding to accelerate crop improvement. Publication of genome assemblies of major Solanaceae crops and their wild relatives during the last decade has provided information for basic research and breeding programs. This review discusses the current status of Solanaceae genome sequencing studies, as well as genetics and evolutionary insights gained from them. Comparative analyses of the high-quality genome sequences revealed the evolutionary history of the genomes. The studies also shed new insights into the diversification of species accompanied by changes in the sizes, content, and organization of genomes. Annotation of the sequenced genomes further revealed gene networks and the putative function of genes involved in the evolution of a number of phenotypic traits. Future studies with more genomes of other Solanaceae crops and wild relatives from different clades will facilitate the reconstruction of more comprehensive phylogenies and the identification of genetic bases for phenotypic diversification across the family.

Helianthemum songaricum and H. ordosicum are two shrubs disjunctively distributed in Central Asia and northwestern China. For conservation purposes, we used genotyping by sequencing (GBS) to investigate the genetic diversity and genetic structure of their populations. Based on the GBS data, H. songaricum populations showed considerable genetic differences from H. ordosicum populations. Helianthemum songaricum populations also showed a stronger population genetic structure within the isolated valleys in the Tianshan Mountains than was seen in previous studies. We speculated that the two species may represent two cotemporal migration events between the Middle East and Central Asia/Ordos Plateau since the early Pliocene. Due to the intense uplift of the Tianshan Mountains in the late Pliocene, populations of H. songaricum were isolated in different valleys. Subsequently, the cold glacial climate during the Pleistocene intensified the in situ intraspecific differentiation of the species. Based on our single nucleotide polymorphism data, we propose habitat damage by anthropological activities, where the two species inhabit should be urgently prohibited by executive management. In addition, a nursery for germplasm resources should be urgently set up to culture adequate progenies for the purpose of expanding the populations.

Silica-scaled chrysophytes, including several lineages of the class Chrysophyceae, possess morphologically diverse silica scales. Despite their ecological significance, few data on their distribution are available from this region. In this study, we aimed to explore the diversity and distribution of silica-scaled chrysophytes in southeastern Queensland. Samples were collected from different water bodies, and scale morphology was examined using transmission and scanning electron microscopy. Water chemical analyses were conducted to reveal the ecological requirements of the species. A total of 35 taxa were identified, including species from the orders Synurales, Chromulinales, and Paraphysomonadales. Mallomonas pseudocoronata, originally thought to be an endemic of North America and later recorded from Europe, was found in Queensland. Our findings provide valuable floristic data and contribute to the understanding of silica-scaled chrysophytes distribution in Australia. Molecular characterization of these species is crucial to assess endemism and further advance chrysophyte research in the region.