Complete plastid genome structure of 13 Asian Justicia (Acanthaceae) species: comparative genomics and phylogenetic analyses.

BACKGROUND: Justicia L. is the largest genus in Acanthaceae Juss. and widely distributed in tropical and subtropical regions of the world. Previous phylogenetic studies have proposed a general phylogenetic framework for Justicia based on several molecular markers. However, their studies were mainly focused on resolution of phylogenetic issues of Justicia in Africa, Australia and South America due to limited sampling from Asia. Additionally, although Justicia plants are of high medical and ornamental values, little research on its genetics was reported. Therefore, to improve the understanding of its genomic structure and relationships among Asian Justicia plants, we sequenced complete chloroplast (cp.) genomes of 12 Asian plants and combined with the previously published cp. genome of Justicia leptostachya Hemsl. for further comparative genomics and phylogenetic analyses. RESULTS: All the cp. genomes exhibit a typical quadripartite structure without genomic rearrangement and gene loss. Their sizes range from 148,374 to 151,739 bp, including a large single copy (LSC, 81,434-83,676 bp), a small single copy (SSC, 16,833-17,507 bp) and two inverted repeats (IR, 24,947-25,549 bp). GC contents range from 38.1 to 38.4%. All the plastomes contain 114 genes, including 80 protein-coding genes, 30 tRNAs and 4 rRNAs. IR variation and repetitive sequences analyses both indicated that Justicia grossa C. B. Clarke is different from other Justicia species because its lengths of ndhF and ycf1 in IRs are shorter than others and it is richest in SSRs and dispersed repeats. The ycf1 gene was identified as the candidate DNA barcode for the genus Justicia. Our phylogenetic results showed that Justicia is a polyphyletic group, which is consistent with previous studies. Among them, J. grossa belongs to subtribe Tetramerinae of tribe Justicieae while the other Justicia members belong to subtribe Justiciinae. Therefore, based on morphological and molecular evidence, J. grossa should be undoubtedly recognized as a new genus. Interestingly, the evolutionary history of Justicia was discovered to be congruent with the morphology evolution. CONCLUSION: Our study not only elucidates basic features of Justicia whole plastomes, but also sheds light on interspecific relationships of Asian Justicia plants for the first time.

Flora diversity survey and establishment of a plant DNA barcode database of Lomas ecosystems in Peru.

Lomas formations or "fog oases" are islands of vegetation in the desert belt of the west coast of South America, with a unique vegetation composition among the world's deserts. However, plant diversity and conservation studies have long been neglected, and there exists a severe gap in plant DNA sequence information. To address the lack of DNA information, we conducted field collections and laboratory DNA sequencing to establish a DNA barcode reference library of Lomas plants from Peru. This database provides 1,207 plant specimens and 3,129 DNA barcodes data corresponding with collections from 16 Lomas locations in Peru, during 2017 and 2018. This database will facilitate both rapid species identification and basic studies on plant diversity, thereby enhancing our understanding of Lomas flora's composition and temporal variation, and providing valuable resources for conserving plant diversity and maintaining the stability of the fragile Lomas ecosystems.

Rungiafangdingiana (Acanthaceae), a new species from Guangxi, China.

Rungiafangdingiana, a new species of Acanthaceae from Guangxi, China is described and illustrated. This new species belongs to Rungiasect.Rungia, and resembles R.sinothailandica and R.burmanica in the erect perennial herbaceous habit, elliptic leaves and inflorescence form, but differs mainly by the indumentum and the morphology of the bracts and corolla. The pollen and seed micromorphology of this new species are studied, with photographs and a line drawing provided.

The complete chloroplast genome of Rungia pectinata (Acanthaceae).

Rungia pectinata is an important traditional Chinese herbal medicine from the family Acanthaceae. The complete chloroplast genome (cp genome) of the genus Rungia was sequenced for the first time. The cp genome of R. pectinata was 149,627 bp in length. It was consisted of a large single copy (LSC) region (81,976 bp) and a small single copy (SSC) region (16,626 bp), which were separated by two inverted repeats (IRs, 25,511 bp). This plastome contained 114 unique genes, including 80 protein-coding genes, 30 tRNA genes, and four rRNA genes. The overall GC content was 38.0%. Phylogenetic analysis of nine species in Acanthaceae was also conducted. This newly sequenced cp genome will be useful to further evolutionary studies, phylogenetic studies, and pharmacognostic identification in the genus Rungia.

Lysimachia huangsangensis (Primulaceae), a New Species from Hunan, China.

A new species, Lysimachia huangsangensis (Primulaceae), from Hunan, China is described and illustrated. The new species is closely related to L. carinata because of the crested calyx, but differs in the leaf blades that are ovate to elliptic and (3-)4.5-9 × 2-3.4 cm, 2-5-flowered racemes, and the calyx lobes that are ovate-lanceolate and 5-6 × 3-4 mm. The systematic placement and conservation status are also discussed.