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Camellia fascicularis belongs to the family Theaceae and is a plant species with extremely small populations. It is also a second-class national protected plant in China. In recent years, the anti-inflammation, antioxidation, and antitumor effects of C. fascicularis polyphenols and flavonoids have been reported. However, changes in the soil chemistry and microbes after artificial cultivation of C. fascicularis have not been well studied. Therefore, three healthy plants from each different artificial planting year's plot (Age_3, Age_5, and Age_7) were selected, and the chemical properties of the rhizosphere soil and root endophytic microbial communities for different cultivation years of C. fascicularis were studied in Hekou County, China. The accumulation of pathogenic and beneficial microbes in the rhizosphere of C. fascicularis was also discussed. The results show that (1) the alpha diversity in rhizosphere soil was significantly higher than that in roots, and roots recruited more Actinobacteria, which might produce beneficial secondary metabolites for the plant; (2) the total nitrogen in the rhizosphere soil of C. fascicularis cultivated for 7 years was significantly higher than that in the soil cultivated for 3 years; (3) there was no significant difference in the alpha and beta diversity in the rhizosphere soil and root endophytes of C. fascicularis in different cultivation years; (4) there was no difference in the abundance of plant-growth-promoting rhizobacteria (PGPR) in either the rhizosphere soil or roots, but the number of PGPR in roots was higher than that in rhizosphere soil; and (5) the changes in pathogenic fungi and biocontrol fungi in rhizosphere soil were greater than those of endophytic fungi in roots. The results show that there are no significant differences in microbial communities among 3, 5, and 7 years, but the influence of the outside environment on the soil and fungi was greater than that of the roots and bacteria. These results can help us to understand the soil chemical and microbial community changes during the artificial cultivation of C. fascicularis and play an important role in its artificial conservation and breeding, as it is a plant species with extremely small populations. [ABSTRACT FROM AUTHOR]

Buddleja sessilifolia is a plant species with extremely small populations (PSESP) in southwest China. The trial of transplantation failed in our Buddleja outdoor garden, and only succeeded in the flowerpots of greenhouse. In this study, we conducted metagenomic analyses on microbial diversity in bulk soil from wild habitat of B. sessilifolia, the Buddleja garden and the B. sessilifolia pots of greenhouse, and meanwhile analyzed soil physicochemical properties. We aimed to uncover the related soil factors which may influence the transplantation of B. sessilifolia. Our results showed the bulk soil from the wild habitat of B. sessilifolia and the B. sessilifolia pots had significantly richer total potassium content than that from the Buddleja garden. Bacterial order Rhizobiales and archaeal class Nitrososphaeria showed a higher diversity in both the wild habitat and the pot than the garden. Furthermore, soil total potassium content was the most correlated to bacterial community structure of the bulk soil, while soil total nitrogen content and total phosphorus content were most important to archaeal and fungal community structures. We accordingly inferred that B. sessilifolia had a high demand on potassium and microbial Rhizobiales and Nitrososphaeria in soil for its survival. Our findings will contribute to the ex-situ conservation of B. sessilifolia. [ABSTRACT FROM AUTHOR]

The concept of Plant Species with Extremely Small Populations (PSESP) has been employed to guide conservation of threatened plant species in China. Climate change has a high potential to threaten PSESP. As a result, it is necessary to integrate climate change effects on PSESP into conservation planning in China. Here, ecological niche modelling is used to project current and future habitat distributions of six PSESP in China under climate change scenarios and conservation planning software is applied to identify priority conservation areas (PCAs) for these PSESP based on habitat distributions. These results were used to provide proposals for in-situ and ex-situ conservation measures directed at PSESP. It was found that annual precipitation was important for habitat distributions for all six PSESP (with the percentage contribution to habitat distributions ranging from 18.1 % to 74.9 %) and non-climatic variables including soil and altitude have a large effect on habitat suitability of PSESP. Large quantities of PCAs occurred within some provincial regions for these six PSESP (e.g. Sichuan and Jilin for the PSESP Cathaya argyrophylla, Taxus cuspidata, Annamocarya sinensis and Madhuca pasquieri), indicating that these are likely to be appropriate areas for in-situ and ex-situ conservation measures directed at these PSESP. Those nature reserves with large quantities of PCAs were identified as promising sites for in-situ conservation measures of PSESP; such reserves include Yangzie and Dongdongtinghu for C. argyrophylla, Songhuajiangsanhu and Changbaishan for T. cuspidata and Shiwandashanshuiyuanlian for Tsoongiodendron odorum. These results suggest that existing seed banks and botanical gardens occurring within identified PCAs should allocate more resources and space to ex-situ conservation of PSESP. In addition, there should be additional botanical gardens established for ex-situ conservation of PSESP in PCAs outside existing nature reserves. To address the risk of negative effects of climate change on PSESP, it is necessary to integrate in-situ and ex-situ conservation as well as climate change monitoring in PSESP conservation planning. [ABSTRACT FROM AUTHOR]

Background: Amorphophallus albus P. Y. Liu & J. F. Chen (Araceae) is a plant species with extremely small populations (PSESP) and an important economic crop endemic to dry-hot valleys along the Jinsha River. In order to gain information for sustaining the development and conservation of A. albus, we studied the genetic diversity and population structure of this species using microsatellite markers (SSR). In this study, we analysed 364 individuals belonging to 24 populations, including four wild populations and three ex-situ cultivated populations, collected in the provinces Yunnan, Sichuan and Hubei. Results: The population genetic analyses indicated that A. albus possesses moderate genetic diversity with the percentage of polymorphic loci (PPL) from 69.23 to 100%, an expected heterozygosity (He) of 0.504 and an average Shannon's Information Index (I) 0.912. Analysis of molecular variance (AMOVA) indicated that most of the variance (71%) resided within populations and the estimated gene flow (Nm) was 0.61. The results of UPGMA cluster tree, STRUCTURE analyses together with the Mantel test (R2 = 0.352, P < 0.01) indicated that geographically closely located populations are clustered together with some exceptions. Conclusions: Our results showed that A. albus still possesses moderate genetic variation in most of the studied populations, and for now, most cultivated populations were naturally distributed but still some reintroduction exists. For sustaining the present genetic variation, some protections measures are necessary for the wild populations and also for the cultivated ones with high genetic diversity. [ABSTRACT FROM AUTHOR]

Plant Species with Extremely Small Populations, PSESP, is a conservation concept developed in China aimed at rescuing most threatened plant species of China. The PSESP conservation program was first implemented in Yunnan Province in 2005. Here, we review the development and importance of this concept. Current progress based on the Implementation Plan of Rescuing and Conserving China's PSESP (2011–2015) is highlighted. 120 species were targeted for priority conservation under this program. Based on the PSESP guidelines, several key national and provincial projects supporting practical conservation and research in conservation biology were initiated. While a number of conservation objectives were achieved, unexpected challenges have hindered the fulfillment of five goals that the Plan expected to accomplish by 2015. We provide examples of a successful methodology and the factors supporting these techniques, as well as describe the gaps between scientific research and conservation practices. Finally, we emphasize how interdisciplinary conservation efforts involving multi-stakeholder coalitions with representatives from research institutes, government agencies, non-governmental organizations and local communities should be encouraged to achieve successful PSESP conservation. While this review seeks to facilitate China's tremendous plant conservation efforts to help overcome existing and be prepared for future challenges, the PSESP approach could be valuable in other countries for the preservation of threatened plants. [ABSTRACT FROM AUTHOR]

Background Acer yangbiense is a newly described critically endangered endemic maple tree confined to Yangbi County in Yunnan Province in Southwest China. It was included in a programme for rescuing the most threatened species in China, focusing on "plant species with extremely small populations (PSESP)". Findings We generated 64, 94, and 110 Gb of raw DNA sequences and obtained a chromosome-level genome assembly of A. yangbiense through a combination of Pacific Biosciences Single-molecule Real-time, Illumina HiSeq X, and Hi-C mapping, respectively. The final genome assembly is ∼666 Mb, with 13 chromosomes covering ∼97% of the genome and scaffold N50 sizes of 45 Mb. Further, BUSCO analysis recovered 95.5% complete BUSCO genes. The total number of repetitive elements account for 68.0% of the A. yangbiense genome. Genome annotation generated 28,320 protein-coding genes, assisted by a combination of prediction and transcriptome sequencing. In addition, a nearly 1:1 orthology ratio of dot plots of longer syntenic blocks revealed a similar evolutionary history between A. yangbiense and grape, indicating that the genome has not undergone a whole-genome duplication event after the core eudicot common hexaploidization. Conclusion Here, we report a high-quality de novo genome assembly of A. yangbiense , the first genome for the genus Acer and the family Aceraceae. This will provide fundamental conservation genomics resources, as well as representing a new high-quality reference genome for the economically important Acer lineage and the wider order of Sapindales. [ABSTRACT FROM AUTHOR]