Search

Background: Michelia lacei W.W.Smith (Magnoliaceae), was classified as a Plant Species with Extremely Small Populations (PSESP) by the Yunnan Provincial Government in both action plans of 2012 and 2021. This evergreen tree is known for its high ornamental and scientific value, but it faces significant threats due to its extremely small population size and narrow geographical distribution. The study aims to understand the genetic structure, diversity, and demographic history of this species to inform its conservation strategies. Results: The analysis of transcriptome data from 64 individuals across seven populations of M. lacei identified three distinct genetic clusters and generated 104,616 single-nucleotide polymorphisms (SNPs). The KM ex-situ population, originating from Longling County, exhibited unique genetic features, suggesting limited gene flow. The genetic diversity was substantial, with significant differences between populations, particularly between the KM lineage and the OTHER lineage. Demographic history inferred from the data indicated population experienced three significant population declines during glaciations, followed by periods of recovery. We estimated the effective population size (Ne) of the KM and OTHER lineages 1,000 years ago were 85,851 and 416,622, respectively. Gene flow analysis suggested past gene flow between populations, but the KM ex-situ population showed no recent gene flow. A total of 805 outlier SNPs, associated with four environmental factors, suggest potential local adaptation and showcase the species' adaptive potential. Particularly, the BZ displayed 515 adaptive loci, highlighting its strong potential for adaptation within this group. Conclusions: The comprehensive genomic analysis of M. lacei provides valuable insights into its genetic background and highlights the urgent need for conservation efforts. The study underscores the importance of ex-situ conservation methods, such as seed collection and vegetative propagation, to safeguard genetic diversity and promote population restoration. The preservation of populations like MC and BZ is crucial for maintaining the species' genetic diversity. In-situ conservation measures, including the establishment of in-situ conservation sites and community engagement, are essential to enhance protection awareness and ensure the long-term survival of this threatened plant species. [ABSTRACT FROM AUTHOR]

Elucidating the genetic background of threatened species is fundamental to their management and conservation, and investigating the demographic history of these species is helpful in the determination of the threats facing them. The woody species of the genus Magnolia (Magnoliaceae) have high economic, scientific and ecological values. Although nearly half of all Magnolia species have been evaluated as threatened, to date there has been no population genetic study employing Next Generation Sequencing (NGS) technology in this genus. In the present study, we investigate the conservation genomics of Magnolia fistulosa , a threatened species endemic to the limestone area along the Sino-Vietnamese border, using a double digest restriction-site-associated DNA-sequencing (ddRAD-seq) approach. To increase the reliability of our statistical inferences, we employed two approaches, Stacks and ipyrad, for SNP calling. A total of 15,272 and 18,960, respectively, putatively neutral SNPs were generated by Stacks and ipyrad. Relatively high genetic diversity and large population divergence were detected in M. fistulosa. Although higher absolute values were calculated using the ipyrad data set, the two data sets showed the same trends in genetic diversity (π, H e), population differentiation (F ST) and inbreeding coefficients (F IS). A change in the effective population size of M. fistulosa within the last 1 Ma was detected, including a population decline about 0.5–0.8 Ma ago, a bottleneck event about 0.2–0.3 Ma ago, population fluctuations during the last glacial stage, and the recovery of effective population size after the last glacial maximum. Our findings not only lay the foundation for the future conservation of this species, but also provide new insights into the evolutionary history of the genus Magnolia in southeastern Yunnan, China. [ABSTRACT FROM AUTHOR]

The slipper orchid Paphiopedilum gratrixianum is a rare and endangered species found in southern China, Laos, Thailand, and Vietnam. In 2021, a population of approximately 150 mature individuals was discovered in Zhenyuan County, Yunnan Province, with additional populations found in Shiping County and Mojiang County. All of the approximately 500 known individuals occur outside of protected areas, making urgent conservation efforts necessary. Steps such as establishing conservation sites, increasing awareness and enforcement, and developing propagation and preservation technologies are needed to prevent the extinction of these populations. Further research on the species' genetic diversity, pollination ecology, and seed germination is also recommended. [Extracted from the article]

Paraboea nanxiensis Lei Cai & Gui L. Zhang, a new species of Gesneriaceae from karst area around the Sino,Vietnamese border, is described here. The new species is morphologically similar to P. nutans D. Fang & D. H. Qin in the shape and indumentum characters of leaf blade, color of flower, length of the inflorescence and glabrous pistil, but it can be easily distinguished by the shape of the corolla, the color of flower interior, the shape and indumentum of calyx lobes, and capsule morphology. The detailed descriptions, color photographs, distribution and ecology, as well as its morphological relationship with similar species are also provided. In recent years, many new taxa or newly record species have been found in limestone areas along the Sino Vietnam border, it is necessary to strengthen the investigation of plant diversity for better understanding the high biodiversity in this area. [ABSTRACT FROM AUTHOR]

A new species of Gesneriaceae, Oreocharis argentifolia Lei Cai & Z.L.Dao from Mengzi City, Yunnan Province, China, is described and illustrated. The new species is morphologically most similar to O. panzhouensis Lei Cai, Y.Guo & F.Wen in plant habit, number of stigma lobes and stamens, and the shape of the calyx, but differs in the shape of the leaf blade, indumentum, shape and color of corolla and the adnate position of the filaments. A detailed description, color photographs, distribution and habitat, as well as its morphological relationship with relevant similar species are also provided. [ABSTRACT FROM AUTHOR]

Isotrema hei Lei Cai & X.X. Zhu, a new species of Aristolochiaceae from Wenshan City, southeastern Yunnan, China, is described and illustrated. It resembles I. kunmingense and I. liangshanense in the shape and structure of the flower, but can be distinguished from both by the shape of leaf blade, bractlet and gynostemium; by the indumentum of petiole, leaf blade, bractlet and lower tube; and by the flower colour. [ABSTRACT FROM AUTHOR]

The rare and threatened fern Christensenia aesculifolia of South-east Asia is listed in China as a second-ranked plant for national protection and is also categorized as one of 62 plant species with extremely small populations by the Yunnan provincial government. Field investigations during 2014–2017 failed to relocate one previously known population, and revealed that the single known extant population of C. aesculifolia contains only 10 individual plants. The most urgent conservation requirement for this species is to conserve the threatened habitat of the remnant population. Further field surveys and research are also required for an improved understanding of the species' status. [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]