No abstract

The complete chloroplast genome sequence of Hibiscus syriacus L. is presented in this study. The genome is composed of 161 019 bp in length, with a typical circular structure containing a pair of inverted repeats of 25 745 bp of length separated by a large single-copy region and a small single-copy region of 89 698 bp and 19 831 bp of length, respectively. The overall GC content is 36.8%. One hundred and fourteen genes were annotated, including 81 protein-coding genes, 4 ribosomal RNA genes and 29 transfer RNA genes.

Plant endophyte and epiphyte communities cooperatively interact with their host plants and play crucial roles in sustaining plant fitness. In Korea, a variety of studies have been conducted to elucidate the reasons for the declining population of the endangered Korean fir (Abies koreana), but the relationship between microbiota and the healthy condition of trees remains unclear. Here, we conducted bacterial 16S rRNA gene and fungal ITS sequence analyses to dissect the composition of endophytic and epiphytic microbiota in both live and dead trees located in the same Mt. Jiri habitat. In the live trees, the bacterial class Armatimonadia and the lichenized fungi groups were significantly dominant, whereas many bacterial and fungal taxa mainly found in rotten wood were enriched in the dead trees. Functional prediction of the microbial communities in live trees suggested the possibility that bacterial endophytes and epiphytes play a role in inorganic nutrient metabolism and fungal endophytes and epiphytes produce biologically active secondary metabolites, thereby contributing to the healthy condition of Korean fir trees. The ecological function of endophytes and epiphytes in dead trees was predicted to be involved in the decomposition of wood for nutrient recycling. Our analyses revealed a distinct difference in microbial communities depending on the health condition of Korean fir trees. The results from this study would be useful for understanding the ecological function of endophytic and epiphytic microorganisms to conserve and manage this endangered species from ecologically vulnerable environments.

Monodehydroascorbate reductase (MDHAR) isan important enzyme that plays a role in the detoxification of reactive oxygen species (ROS) by maintaining reduced pool of ascorbate through recycling the oxidized form of ascorbate. In this study, we isolated a PagMDHAR1 gene from Populus alba × P. glandulosa, and investigated its expression characteristics. The PagMDHAR1 cDNA encodes a putative 434 amino acids containing FAD-and NAD(P)H-binding domains. Southern blot analysis indicated that a single nuclear gene encodes this enzyme. Northern hybridization analysis revealed that PagMDHAR1 is highly expressed in both suspension cells and flower tissues, while its expression levels were enhanced by drought, salt, cold, wounding and ABA. Therefore, PagMDHAR1 might be expressed in response to abiotic stress through the ABA-mediated signaling pathway in this poplar species, suggesting that the PagMDHAR1 plays an important role in the defense mechanisms against oxidative stress.