Search Results (7)

Neocosmospora (Nectriaceae) is a globally distributed fungal genus, traditionally recognized as a group of plant pathogens, with most members known to cause severe plant diseases. However, recent studies have demonstrated that many of these fungi can also colonize plants endophytically, with certain strains capable of promoting plant growth and stimulating the production of secondary metabolites. In this study, 13 strains of Neocosmospora were isolated from the stems and leaves of Dracaena cambodiana and D. lourei in Yunnan Province, China. To clarify the taxonomic placement of these strains, morphological examination and multi-gene (ITS, nrLSU, tef1, rpb1, and rpb2) phylogenetic analyses were performed. Based on morphological and phylogenetic evidence, four new species are introduced and described here: N. hypertrophia, N. kunmingense, N. rugosa, and N. simplicillium. This study expands our understanding of the fungal diversity associated with Dracaena, provides essential data for the taxonomy of Neocosmospora, and serves as a resource for the future development and utilization of Neocosmospora endophytes. Full article

Ultraviolet-B (UV-B) radiation is a major abiotic stress that dragon trees are exposed to during their growth and development; however, it is also an environmental signal perceived by plants that affects the flavonoid pathway. Previous studies have demonstrated that amounts of flavonoids are contained in dragon tree resin, otherwise known as dragon’s blood. However, the traits and mechanism involved in the UV-B-mediated increase in flavonoids in dragon trees are still unknown. Here, we studied the response of Dracaena cambodiana under full solar UV-B radiation. The results showed that the contents of total flavonoids in D. cambodiana significantly increased after UV-B radiation exposure. Then, the transcriptome was used for determining the interactive mechanism of flavonoid accumulation and UV-B stress. Differential expression analyses identified 34 differentially expressed genes (DEGs) involved in flavonoid synthesis; specifically, 24 of the identified DEGs were significantly up-regulated after UV-B radiation exposure. In addition, 57 DEGs involved in Ca²⁺/kinase sensors, 58 DEGs involved in ROS scavenging and the plant hormone pathway, and 116 DEGs transcription factors in 5 families were further identified and analyzed. Finally, we deduced the potential mechanism of UV-B-promoting flavonoid formation to neutralize ROS damage derived from UV-B radiation in D. cambodiana based on the gene co-expression network and previous studies from other plants. Considering that wild dragon tree populations are currently highly threatened by anthropogenic and natural stressors, the interactive studies between D. cambodiana plants and UV-B radiation provide valuable information toward understanding the mechanism of dragon’s blood formation and help us reveal the evolution of D. cambodiana, with the eventual goal of aiding in the global conservation of this precious biological resource. Full article

Two new names, Dracaena neoparviflora and Dracaena ridleyii are proposed as replacement names for the illegitimate names D. parviflora Baker, and D. nutans Ridl., respectively, the latter being a later homonym of D. parviflora Willd. ex Schult.f., and D. nutans H.Jaeger. Lectotypes are designated for D.cambodiana, D. interrupta (synonym of D. camerooniana), D. oddonii (synonym of D. camerooniana), D. cantleyi, D. cinnabari, D. cuspidibracteata (synonym of D. congoensis), D. haemanthoides, D. litoralis (synonym of D. braunii), D. parviflora, D. novoguineensis, D. nutans, D. petiolata, D. reflexa var. linearifolia, D. reflexa var. angustifolia, D. steudneri, D. tessmannii (synonym of D. mannii), and D. viridiflora. The second-step lectotypications are made for D. camerooniana, D. bushii, D. glomerata, D. papahu (synonym of D. steudneri), D. talbotii (synonym of D. bicolor), D. vaginata (synonym of D. viridiflora), and D. xiphophylla. A neotype is designated for the name Aletris arborea (basionym of D. arborea). Full article

The Socotra dragon`s blood tree (Dracaena cinnabari Balf.) is endemic to the island of Socotra in Yemen. This iconic species plays an essential role in the survival of associated organisms, acting as an umbrella tree. Overexploitation, overgrazing by livestock, global climate change, and insufficient regeneration mean that the populations of this valuable species are declining in the wild. Although there are many studies on the morphology, anatomy, and physiology of D. cinnabari, no genomic analysis of this endangered species has been performed so far. Therefore, the main aim of this study was to characterize the complete chloroplast sequence genome of D. cinnabari for conservation purposes. The D. cinnabari chloroplast genome is 155,371 bp with a total GC content of 37.5%. It has a quadripartite plastid genome structure composed of one large single-copy region of 83,870 bp, one small single-copy region of 18,471 bp, and two inverted repeat regions of 26,515 bp each. One hundred and thirty-two genes were annotated, 86 of which are protein-coding genes, 38 are transfer RNAs, and eight are ribosomal RNAs. Forty simple sequence repeats have also been identified in this chloroplast genome. Comparative analysis of complete sequences of D. cinnabari chloroplast genomes with other species of the genus Dracaena showed a very high conservativeness of their structure and organization. Phylogenetic inference showed that D. cinnabari is much closer to D. draco, D. cochinchinensis, and D. cambodiana than to D. terniflora, D. angustifolia, D. hokouensis, and D. elliptica. The results obtained in this study provide new and valuable omics data for further phylogenetic studies of the genus Dracaena as well as enable the protection of genetic resources of highly endangered D. cinnabari. Full article

Dragon’s blood that is extracted from Dracaena plants has been widely used as traditional medicine in various ancient cultures. The application of dragon’s blood has a cherished history in China, even though the original plants were not discovered for some period. Dracaena cochinchinensis and Dracaena cambodiana were successively discovered in southern China during the 1970s–1980s. In the last half of the century, Chinese scientists have extensively investigated the production of dragon’s blood from these two Dracaena species, whereas these results have not been previously systematically summarized, as in the present paper. Herein, we present the applied history in ancient China and artificially induced technologies for dragon’s blood development based on these two Dracaena species, in particular, using tissue cultures seedlings and tender plants of D. cambodiana. Big data research, including transcriptomic and genomic studies, has suggested that dragon’s blood might be a defense substance that is secreted by Dracaena plants in response to (a)biotic stimuli. This review represents an effort to highlight the progress and achievements from applied history as well as induction techniques that are used for the formation of dragon’s blood that have taken place in China. Such knowledge might aid in the global conservation of wild Dracaena species and contribute to understanding dragon blood formation mechanisms, eventually assisting in the efficient utilization of limited Dracaena plant resources for the sustainable production of dragon’s blood. Full article

Dracaena draco, which belongs to the genus Dracaena, is an endemic succulent of the Canary Islands. Although it is one of the most popular and widely grown ornamental plants in the world, little is known about its genomic variability. Next generation sequencing, especially in combination with advanced bioinformatics analysis, is a new standard in taxonomic and phylogenetic research. Therefore, in this study, the complete D. draco chloroplast genome (cp) was sequenced and analyzed in order to provide new genomic information and to elucidate phylogenetic relationships, particularly within the genus Dracaena. The D. draco chloroplast genome is 155,422 bp, total guanine-cytosine (GC) content is 37.6%, and it has a typical quadripartite plastid genome structure with four separate regions, including one large single copy region of 83,942 bp length and one small single copy region of 18,472 bp length, separated by two inverted repeat regions, each 26,504 bp in length. One hundred and thirty-two genes were identified, 86 of which are protein-coding genes, 38 are transfer RNAs, and eight are ribosomal RNAs. Seventy-seven simple sequence repeats were also detected. Comparative analysis of the sequence data of various members of Asparagales revealed mutational hotspots potentially useful for their genetic identification. Phylogenetic inference based on 16 complete chloroplast genomes of Asparagales strongly suggested that Dracaena species form one monophyletic group, and that close relationships exist between D. draco, D. cochinchinensis and D. cambodiana. This study provides new and valuable data for further taxonomic, evolutionary and phylogenetic studies within the Dracaena genus. Full article

The antioxidant activities of the petroleum ether, ethyl acetate, n-BuOH and water extract fractions from Dracaena cambodiana Pierre ex Gagnep were evaluated in this study. The ethyl acetate fraction contained the highest amount of total phenolics and total flavonoids, and showed the greatest DPPH˙, ABTS⁺ and Superoxide anion radical-scavenging capacities. The DPPH˙, ABTS⁺ and Superoxide anion radical-scavenging capacities of nine compounds isolated from the ethyl acetate fraction were also evaluated. The results indicated that these compounds contributed to the antioxidant activity of D. cambodiana. Therefore, D. cambodiana and these compounds might be used as natural antioxidants. Full article