Genetic diversity and structure of the endemic and endangered species Aristolochia delavayi growing along the Jinsha River

The reduced growth due to elevated CO2 concentration hinders the sexual reproduction of mature Northern pipevine (Aristolochia contorta Bunge)

The phenology has gained considerably more attention in recent times of climate change. The transition from vegetative to reproductive phases is a critical process in the life history of plants, closely tied to phenology. In an era of climate change, understanding how environmental factors affect this transition is of paramount importance. This study consisted of field surveys and a greenhouse experiment on the reproductive biology of Northern pipevine (Aristolochia contorta Bunge). During field surveys, we investigated the environmental factors and growth characteristics of mature A. contorta, with a focus on both its vegetative and reproductive phases. In its successful flowering during the reproductive phase, A. contorta grew under the conditions of 40% relative light intensity and 24% soil moisture content, and had a vertical rhizome. In the greenhouse experiments, we examined the impact of increased CO2 concentration on the growth and development of 10-year-old A. contorta, considering the effect of rhizome direction. Planted with a vertical rhizome direction, A. contorta exhibited sufficient growth for flowering under ambient CO2 concentrations. In contrast, when planted with a horizontal rhizome direction, it was noted to significantly impede successful growth and flowering under elevated CO2 concentrations. This hindered the process of flowering, highlighting the pivotal role of substantial vegetative growth in achieving successful flowering. Furthermore, we observed a higher number of underground buds and shoots under the conditions of elevated CO2 concentration and a horizontal rhizome direction instead of flowering. Elevated CO2 concentrations also exhibited diverse effects on mature A. contorta's flower traits, resulting in smaller flower size, shorter longevity, and reduced stigma receptivity, and pollen viability. The study shed light on elevated CO2 concentrations can hinder growth, potentially obstructing sexual reproduction and diminishing genetic diversity.

Phylogeographic analysis reveals extensive genetic variation of native grass Elymus nutans (Poaceae) on the Qinghai-Tibetan plateau

Introduction

Elymus nutans holds ecological and pastoral significance due to its adaptability and nutritional value, the Qinghai-Tibet Plateau (QTP) is a key hub for its genetic diversity. To conserve and harness its genetic resources in highland ecosystems, a thorough assessment is vital. However, a comprehensive phylogeographic exploration of E. nutans is lacking. The objective of this study was to unravel the genetic diversity, adaptation, and phylogenetics of E. nutans populations.

Methods

Encompassing 361 individuals across 35 populations, the species' genetic landscape and dynamic responses to diverse environments were decoded by using four chloroplast DNA (cpDNA) sequences and nine microsatellite markers derived from the transcriptome.

Results and discussion

This study unveiled a notable degree of genetic diversity in E. nutans populations at nuclear (I = 0.46, He = 0.32) and plastid DNA levels (Hd = 0.805, π = 0.67). Analysis via AMOVA highlighted genetic variation predominantly within populations. Despite limited isolation by distance (IBD), the Mekong-Salween Divide (MSD) emerged as a significant factor influencing genetic differentiation and conserving diversity. Furthermore, correlations were established between external environmental factors and effective alleles of three EST-SSRs (EN5, EN57 and EN80), potentially linked to glutathione S-transferases T1 or hypothetical proteins, affecting adaptation. This study deepens the understanding of the intricate relationship between genetic diversity, adaptation, and environmental factors within E. nutans populations on the QTP. The findings shed light on the species' evolutionary responses to diverse ecological conditions and contribute to a broader comprehension of plant adaptation mechanisms.

Transcriptome data reveals the conservation genetics of Cypripedium forrestii, a plant species with extremely small populations endemic to Yunnan, China

The Cypripedium forrestii is an orchid species with extremely small populations (PSESP) in Yunnan, China. C. forrestii is range-restricted and less-studied than many orchid species, and it is exposed to various threats to its survival. We investigated its potential habitats and collected 52 samples from eight locations, as well as two outgroup species for reference. We developed genetic markers (SNPs) for C. forrestii based on transcriptome sequencing (RNA-seq) data, and analyzed the genetic diversity, population structure, gene flow and demographic history of C. forrestii in detail. C. forrestii is a taxonomically independent species to protect. We found that the genetic diversity of C. forrestii was very low (1.7e-4) compared with other endangered species. We identified three genetic clusters, and several populations with distinct genetic backgrounds. Most genetic diversity was found within sampling sites (87.87%) and genetic clusters (91.39%). Gene flow has been greatly limited over the most recent generations, probably due to geographical distance, historical climate change and habitat fragmentation. We also detected a severe bottleneck event brought about by the recent population constraints. These factors, together with its reproductive characteristics, contribute to the population fragmentation and low genetic diversity of C. forrestii. Based on our findings, we suggest an integrative conservation strategy to protect and recover the genetic diversity of C. forrestii and a further comprehensive study of its ecological traits in the future.

SSR molecular marker developments and genetic diversity analysis of Zanthoxylum nitidum (Roxb.) DC

Zanthoxylum nitidum (Roxb.) is a commonly used traditional Chinese medicine. However, the collection and protection of wild germplasm resources of Z. nitidum are still insufficient, and there is limited research on its genetic diversity and fingerprint. In the present study, 15 simple sequence repeat (SSR) markers were developed by genotyping based on multiplexed shotgun sequencing. The genetic diversity of 51 populations (142 individuals) of Z. nitidum was evaluated using these 15 SSRs. A total of 245 alleles (Na) were detected, with an average value of 16.333, and the average polymorphism information content was 0.756. The genetic distance among 51 populations was 0.164~1.000, with an average of 0.659. Analysis of molecular variance showed low genetic differentiation (40%) and high genetic differentiation (60%) between populations and individuals, respectively. The genetic differentiation coefficient (Fst) of the population was 0.338, indicating that 66.2% of the genetic variation occurred within the population, and the gene flow (Nm) was 0.636, demonstrating that the gene exchange between populations was low. Clustering analysis revealed that the genetic similarity coefficient was 0.30, dividing the 51 populations into 4 groups of 2, 17, 3, and 29 populations. There was no specific relationship between geographical location differences and genetic distance. The genetic diversity level of Z. nitidum is relatively high, and our results provide a theoretical basis for the rapid identification of Z. nitidum germplasm resources and variety selection.

Population Genetics, Genetic Structure, and Inbreeding of Commiphora gileadensis (L.) C. Chr Inferred from SSR Markers in Some Mountainous Sites of Makkah Province

Commiphora gileadensis (L.) C. Chr is a perennial plant existing mainly in the southern and western mountains of the Arabian Peninsula. In the Makkah province, the remaining populations are threatened by many factors such as overcutting, overgrazing, and urban developments. These dangers are expected to be aggravated by the progression of aridification factors arising from climate change. To overcome the decline in remaining populations of this valuable species, a timely evaluation of the population's genetic variables and genetic structure is vital for the conservation of existing C. gileadensis populations. In this study, we used 61 SSR primers to achieve this objective. Only 50 loci showed polymorphisms, which led to further analysis of the population genetics for 600 genotypes that were collected from 50 populations of C. gileadensis found in 10 different sites in the Makkah region: Gebel Al Muliesaa, Wadi Albathna, Wadi Houra, Wadi Albaidaa, Wadi Elebiedia, Gebel Kniethl, Wadi Sayaa, Wadi Elbarasa, Wadi Alfawara, and Wadi Alkharar. The results showed an obvious decrease in genetic diversity variables in all studied populations. The range of PPL was between 8 and 40; additionally, the low H_T value of 0.804 and the high value of inbreeding, F_is = 0.238, reflected a severe lack of heterozygotes. High levels of F_ST and G_ST and low gene flow indicate considerable segregation among the C. gileadensis populations, which creates a barrier to gene migration. Our data suggest the need for conservation planning for C. gileadensis in order to avoid the species' forthcoming extinction. Efforts should be largely oriented around managing water consumption, prohibiting overcutting and overgrazing, and establishing appropriate seed banks.

Diversity and Genetic Structure of Scarlet Plume (Euphorbia fulgens), an Endemic Plant of Mexico

Euphorbia fulgens is an ornamental species cultivated in Europe and endemic to Mexico; its ecological, genetic, and evolutionary aspects are not known. The objectives of this study were to determine its distribution, describe the places it inhabits, and analyze the diversity and genetic structures of wild populations of E. fulgens. A bibliographic review of the herbarium specimens and a field evaluation were carried out to develop a potential distribution map based on a multi-criteria analysis of the climatic and topographic variables. Three populations (forty-five individuals) from pine–oak and cloud forests located in the Southern Sierra of Oaxaca were analyzed using ten microsatellite loci. The analysis was conducted using Arlequin v. 3.5, Mega v. 10, and Structure v. 2.3 programs. Eight loci were polymorphic, and a total of thirty-eight alleles were obtained. The average number of alleles per polymorphic locus was 4.6. The average heterozygosity of the three populations was high (Ho = 0.5483), and genetic differentiation between populations were low, with a high genetic flow, suggesting that it could be an ancestral population that became fragmented and was just beginning to differentiate genetically. The information generated on this restricted distribution species can be used in conservation programs pertaining to human activities that endanger the habitats where it is found.