Aster L. is an economically and phylogenetically important genus in the tribe Astereae. Here, the complete plastomes of the eight Aster species were assembled and characterized using next-generation sequencing datasets. The results indicated the complete plastomes of Aster had a quadripartite structure. These genomes were 152,045–152,729 bp in length and contained 132–133 genes, including 87 protein-coding genes, 37–38 tRNA genes, and eight rRNA genes. Expansion or contraction of inverted repeat regions and forward, palindromic, complement, and reverse repeats were detected in the eight Aster species. Additionally, our analyses showed the richest type of simple sequence repeats was A/T mononucleotides, and 14 highly variable regions were discovered by analyzing the border regions, sequence divergence, and hotspots. Phylogenetic analyses indicated that 27 species in Astereae were clustered into six clades, i.e., A to D, North American, and outgroup clades, and supported that the genera Heteropappus, Kalimeris, and Heteroplexis are nested within Aster. The results indicated the clades B to D might be considered as genera. Divergence time estimate showed the clades A, B, C, and D diverged at 23.15 Mya, 15.13 Mya, 24.29 Mya, and 21.66 Mya, respectively. These results shed light on the phylogenetic relationships of Aster and provided new information on species identification of Aster and its related genera.

Angiosperms are the largest group of land plants with ~375,000 species, which are classified into ~416 families and ~13,000 genera; they exhibit tremendous morphological and physiological diversities and are important members of diverse terrestrial and aquatic ecosystems. Angiosperms have attracted continuous efforts to describe and understand these diversities in a framework of interrelationships—the phylogeny, which provides strong support for angiosperm classifications and relies on morphological, anatomical, and increasing molecular markers. Today, great advances in sequencing technology have led to the generation of tens of thousands of gene sequences for individual species, facilitating angiosperm phylogenetic reconstruction with high resolution at both deep and shallow levels. In this review, we present recent insights into angiosperm phylogeny based on relatively large numbers of nuclear genes, encompassing the ordinal scale of early-divergent and backbone branches, eudicots and their major subclades, asterids and rosids, as well as monocots. We further delve into intra-order cases such as Caryophyllales (Eudicots) and Alismatales (Monocots), along with intra-family relationships for some of the largest families (e.g., Asteraceae, Orchidaceae, Fabaceae, and Poaceae) and those with economic importance (such as Brassicaceae, Solanaceae, Cucurbitaceae, and Rosaceae). Furthermore, we briefly highlight the importance of nuclear phylogeny in addressing key evolutionary questions, including the origin and divergence of angiosperms, the evolution of morphological and other characters, gene duplication and other aspects of gene family evolution. Finally, we discuss possible future trends of angiosperm phylogenomics.

Asteraceae, the largest family of flowering plants, comprises more than 26,000 species worldwide, many of which serve as crops, medicinal herbs, and ornamentals. While substantial genomic resources are available for nuclear and chloroplast genomes, mitochondrial genomes (mitogenomes) in this family remain poorly explored, limiting an integrated understanding of its genomic evolution. Here, we assembled 38 complete mitogenomes representing 12 subfamilies and 22 tribes. Our analyses revealed substantial size variation, with notably larger mitogenomes in early-diverging lineages. We also observed extensive structural rearrangements across subfamilies and tribes. Although the gene content is largely conserved, we identified notable mutations, horizontal gene transfer events, and losses of RNA editing sites. We reconstructed a comprehensive mitochondrial phylogeny of Asteraceae, which revealed both congruent and conflicting relationships with phylogenies based on plastid and nuclear markers. Furthermore, our fragment analysis of total mitochondrial DNA demonstrated that the differential retention of ancestral sequences significantly influences mitogenome size variation in Asteraceae. This study provides a systematic mitogenomic resource, offering novel insights into the evolutionary dynamics of this major plant family.

Aster xuelinii, a new species from Gansu Province, China, is described and illustrated based on morphological and phylogenetic evidence. The new species is superficially similar to A. dolichopodus Y. Ling in that both have nearly entire leaves, synflorescence solitary at branch tips or arranged in corymbiform clusters, and ray floret color. However, it differs from A. dolichopodus in having peduncles 6–9 cm in length and 12–14 ray florets, versus 2.5–15 cm in length and 19–26 ray florets. Phylogenetic analyses of nuclear ribosomal ITS and ETS sequences, as well as the chloroplast trnL-F region, place this new species within the genus Aster, where it forms a well-supported clade with A. taliangshanensis Y. Ling. A. xuelinii differs from A. taliangshanensis in that the latter has stems often purplish-red in the upper part, capitula typically arranged 1–3 at branch tips forming a loosely corymbiform synflorescence, and a higher number of ray florets (50–60), which are bluish-purple. Furthermore, detailed morphological descriptions, diagnostic illustrations, and ecological habitat characteristics are provided, supporting the classification of this new species.