Centaurea cyanus has been a weed in farmland for a long time. In this study, the chloroplast genome of C. cyanus was sequenced to establish the phylogenetic relationship between its genomic characteristics and other related species. The chloroplast gene structure of C. cyanus is a circular molecule with a length of 152,433 bp, including a large single-copy (LSC) region of 83,464 bp, a small single-copy (SSC) region of 18,545 bp, and a pair of inverted repeats sequences (IRs) region of 25,212 bp. The whole genome contains 130 genes, including 86 protein-coding genes, 36 tRNA genes, and eight rRNA genes. Phylogenetic analysis showed that C. cyanus is close to Carthamus. tinctorius, C. tinctorius, C. diffusa, and C. maculosa, and all of them were in one clade. This study provides genetic resource information for the further study of Centaurea.

Plants have evolved various self-defense mechanisms against insect feeding. There are many reports regarding both direct and indirect defense mechanisms in seed-plant. However, only direct defenses on ferns were considered and the indirect defense mechanism has never been reported. In this study, it was observed that the fern Hypolepis punctata can attract the assassin bug Sclomina erinacea in the field. We collected and analyzed volatiles from H. punctata healthy individuals and the ones wounded by Bertula hadenalis, using dynamic headspace and GC-MS. We recorded the electroantennogram responses of antennae of S. erinacea to different standards of volatile compounds identified from the GC-MS analysis. We also analyzed the behavior of male and female S. erinacea adults in response to volatiles collected from H. punctata using a Y-tube olfactometer. The results showed that a number of volatile compounds were produced when the fern was damaged by B. hadenalis. Electroantennography and Y-tube olfactometer results showed that some herbivore-induced volatiles and volatiles from undamaged leaves could attract S. erinacea. Our research suggests that H. punctata can attract insect predators by releasing herbivory-induced volatile organic compounds, and for the first time we found ferns may also have indirect defense mechanisms using volatile organic compounds.

Galium spurium is a farmland weed, with strong stress resistance. However, its chloroplast genome has never been reported. In this study, the complete sequence of the chloroplast genome of G. spurium was characterized, which is a circular molecule, 153,481 bp in length, and with a large single copy region of 84,334 bp, a small single copy region of 17,057 bp, and a pair of inverted repeat regions of 26,045 bp. The whole genome contained 127 genes, including 82 protein-coding genes, 37 transfer RNA genes, and eight ribosomal RNA genes. Phylogenetic analysis shows that it relates closely to G. aparine. This study provides a basis for the further phylogenic study of Galium.

Gomesa flexuosa (Lodd) M.W.Chase & N.H.Williams is a new species of orchid revised in 2009. In this study, the chloroplast genome of G. flexuosa was sequenced to determine its genomic characteristics and phylogenetic relationship with other related species. G. flexuosa has a chloroplast genome size of 147,764 bp, comprising 25,757 bp of two inverted repeat (IR) regions, 83,579 bp of large single-copy (LSC) region, and 12,671 bp of small single-copy (SSC) region. Moreover, the whole genome contains 73 protein-coding genes, 38 tRNA genes, and eight rRNA genes. Phylogenetic analysis showed that G. flexuosa is closely related to Oncidium sphacelatum.

Sedum bulbiferum is a traditional medicinal plant in China, with few reports on its chloroplast genome. In this study, the chloroplast genome of Sedum bulbiferum was characterized, and its phylogenetic position among other closely related species was studied. The results showed that the full length of the chloroplast genome was 150,074 bp, containing a large single-copy (LSC) region and a small single-copy (SSC) region of 81,730 and 16,726 bp, respectively, as well as two inverted repeat regions (IRs) of 25,809 bp like other plants. A total of 128 genes were found, including 83 protein-coding genes, 37 tRNA genes, and eight rRNA genes. Phylogenetic analysis showed that Sedum bulbiferum is closely related to Sedum emarginatum, Sedum alfredii, Sedum tricarpum, Sedum plumbizincicola, and Sedum sarmentosum.

The Diospyros genus (Ebenaceae) has significant economic value. During field surveys, we discovered a Diospyros specimen showing morphological overlap with both D. oleifera and D. kaki var. silvestris, provisionally named Diospyros aff. oleifera. To resolve its taxonomy, we sequenced and analyzed its chloroplast genome. The complete chloroplast genome is 157,732 bp with a quadripartite structure. mVISTA analysis revealed unique sequence variations compared to related species. Phylogenetic analysis using 75 protein-coding genes grouped it with D. oleifera, indicating their close relationship. Our findings suggest this specimen likely represents a novel, undescribed species. This study provides insights into Diospyros diversity and a foundation for future research.