Primula, well known for its heterostyly, is the largest genus in the family Primulaceae with more than 500 species. The considerable species number has introduced a huge challenge for taxonomy. The phylogenetic relationships among Primula still maintain unresolved due to frequent hybridization and introgression between closely related species. In this study, we sequenced and assembled the complete chloroplast genomes of Primula wilsonii Dunn, which is a PSESP (plant species with extremely small populations), using Illumina sequencing and compared its genomic sequences with those of four related Primula species. The chloroplast genomes of Primula species were similar in the basic structure, gene order, and GC content. The detected 38 SSRs (simple sequence repeats) loci and 17 hypervariable regions had many similarities in P. wilsonii, P. anisodora, P. miyabeana, and P. poissonii, but showed a significant difference compared with those in P. secundiflora. Slight variations were observed among Primula chloroplast genomes, in consideration of the relatively stable patterns of IR (inverted repeats) contraction and expansion. Phylogenetic analysis based on chloroplast genomes and protein‐coding genes confirmed three major clades in Chinese Primula, but the infrageneric sections were not in accordance with morphological traits. The P. poissonii complex was confirmed here and P. anisodora was the most closely related species to P. wilsonii. Overall, the chloroplast genome sequences provided useful genetic and evolutionary information for phylogeny and population genetics on Chinese Primula species.

There is discussion over whether pollen limitation exerts selection on floral traits to increase floral display or selects for traits that promote autonomous self‐fertilization. Some studies have indicated that pollen limitation does not mediate selection on traits associated with either pollinator attraction or self‐fertilization.Primula tibeticais an inconspicuous cross‐fertilized plant that may suffer from pollen limitation. We conducted a selection analysis onP. tibeticato investigate whether pollen limitation results in selection for an increased floral display in case the evolution of autonomous self‐fertilization has been difficult for this plant. The self‐ and intra‐morph incompatibility features, the capacity for autonomous self‐fertilization, and the magnitude of pollen limitation were examined through hand‐pollination experiments. In 2016, we applied selection analysis on the flowering time, corolla width, stalk height, flower tube length, and flower number inP. tibeticaby tagging 76 open‐pollinated plants and 37 hand‐pollinated plants in the field. Our results demonstrated thatP. tibeticawas strictly self‐ and intra‐morph incompatible. Moreover, the study population underwent severe pollen limitation during the 2016 flowering season. The selection gradients were found to be significantly positive for flowering time, flower number, and corolla width, and marginally significant for the stalk height. Pollinator‐mediated selection was found to be significant on the flower number and corolla width, and marginally significant on stalk height. Our results indicate that the increased floral display may be a vital strategy for small distylous species that have faced difficulty in evolving autonomous self‐fertilization.

Background: Pollen limitation occurs widely and has an important effect on flowering plants. The East Himalaya-Hengduan Mountains region is a global biodiversity hotspot. However, to our knowledge, no study has synthetically assessed the degree of pollen limitation in this area. The present study aims to reveal the degree of pollen limitation for the flowering plants growing on East Himalaya-Hengduan Mountains and to test whether the reproductive features or the elevation is closely correlated with the degree of pollen limitation in this area. Results: We complied data from 76 studies, which included 96 species and 108 independent data records. We found that the flowering plants in this area undergo severe pollen limitation [overall Hedges’ d = 2.004, with a 95% confidence interval (1.3264, 2.6743)] that is much higher than that of the flowering plants growing in many other regions around the world. The degree of pollen limitation was tested to determine the correlation with the capacity for autonomous self-reproduction and with the pollination pattern (generalized vs. specialized pollination) of plants. In addition, we found a clear relationship between elevation and the degree of pollen limitation, which indicates that plants might undergo more severe pollen limitation in relatively high places. Conclusions: This paper is the first to address the severe pollen limitation of the flowering plants growing in East Himalaya-Hengduan Mountains region. Moreover, we reveal the positive correlation between elevation and the degree of pollen limitation.

Iris cangshanensis X. F Jiang, Y. Yang, J. F Liu & Y. P Xie, 2024, is a newly described perennial herb with a small population size. This study utilized Illumina sequencing technology to construct the complete chloroplast genome of Iris cangshanensis. The chloroplast genome is 154,008 base pairs (bp) in size with 37.32% overall GC content, consisting of an 83,559 bp (35.35%) large single-copy region (LSC), a 17,937 bp (30.56%) small single-copy region (SSC), and a pair of 26,256 bp (42.78%) inverted repeat (IR) sequences. The chloroplast genome has 130 genes, including 84 protein-coding genes, 38 tRNA genes, and eight rRNA genes. A maximum-likelihood (ML) phylogenetic analysis based on the plastomes of 15 Iridaceae species revealed that Iris cangshanensis is closely related to the other 12 species within the Iris genus. Owing to the limited chloroplast genome sampling of the genus Iris in the present study, determining the position of Iris cangshanensis in this genus is difficult. Overall, the chloroplast genome reported in this study will be useful for further taxonomic and evolutionary studies of Iris. This study constructs the complete chloroplast genome of Iris cangshanensis. The chloroplast genome is 154,008 base pairs (bp) in size with 37.32% overall GC content, consisting of an 83,559 bp (35.35%) large single-copy region (LSC), a 17,937 bp (30.56%) small single-copy region (SSC), and a pair of 26,256 bp (42.78%) inverted repeat (IR) sequences. The chloroplast genome has 130 genes, including 84 protein-coding genes, 38 tRNA genes, and eight rRNA genes. A maximum-likelihood (ML) phylogenetic analysis based on 15 Iridaceae species revealed that Iris cangshanensis is closely related to the species within the Iris genus.

Introduction: Pseudocydonia sinensis, also known as Chinese quince, is a perennial shrub or small tree highly valued for its edibility and medicinal properties.Method: This study presents the first chromosome-level genome assembly of P. sinensis, achieved using HiFi sequencing and Hi-C scaffolding technology.Results: The assembly resulted in a high-quality genome of 576.39 Mb in size. The genome was anchored to 17 pseudo-chromosomes, with a contig N50 of 27.6 Mb and a scaffold N50 of 33.8 Mb. Comprehensive assessment using BUSCO, CEGMA and BWA tools indicates the high completeness and accuracy of the genome assembly. Our analysis identified 116 species-specific genes, 1196 expanded genes and 1109 contracted genes. Additionally, the distribution of 4DTv values suggests that the most recent duplication event occurred before the divergence of P. sinensis from both Chaenomeles pinnatifida and Pyrus pyrifolia.Discussion: The assembly of this high-quality genome provides a valuable platform for the genetic breeding and cultivation of P. sinensis, as well as for the comparison of the genetic complexity of P. sinensis with other important crops in the Rosaceae family.