Sophora alopecuroides is a perennial drought-tolerant leguminous herb mainly distributed in the northwestern region of China with important medicinal and foraging economic values. We explored the geographical distribution pattern and dominant environmental variables in populations of S. alopecuroides under various climate change scenarios using the MaxEnt model and ArcGIS. Our dataset comprises geographic distribution from 137 sites combined with a temporal element comprising past (Last Interglacial, Last Glacial Maximum, Mid-Holocene), current, and future (2050s, 2070s) predicted environmental variables under four CO2 representative concentration pathways. Results indicate that (1) the result by the MaxEnt model showed that the average Area Under the Curve (AUC) values exceeded 0.9, suggesting that the performance of our model was optimal and reliable; (2) annual mean temperature (bio1), temperature annual range (bio7), mean temperature of driest quarter (bio9), and elevation were the most important variables explaining the model; (3) under current climatic conditions, suitable habitat for S. alopecuroides accounted for 28.9% of the total area of China, which is consistent with the actual distribution of the species; (4) from the Last Interglacial to current period, the center of gravity for the distribution of suitable areas for S. alopecuroides has gradually shifted southeastward by a small distance in response to the ongoing increase in temperature, and is expected to shift northwestwards from the present to the 2050s to the 2070s; and that (5) the Loess Plateau and the Inner Mongolia Plateau may be the origin and are the modern distribution centers of S. alopecuroides.

Understanding the potential effects of climate change on species distribution is vital for the conservation of endangered taxa. The Saxifragaceae family, known to be susceptible to habitat disturbance, has a diverse distribution. While a significant portion is found on the Qinghai-Xizang Plateau (QXP), about half the species of Saxifraga are native to Europe, and other genera, such as Heuchera, have their centers of diversity in regions like North America and Japan. In this study, we employ the Maximum Entropy (MaxEnt) model in conjunction with Shared Socioeconomic Pathways (SSPs) to assess the MaxEnt potential influence of climate change on the distribution and richness of four endangered Saxifragaceae species (Saxifraga cernua L., Saxifraga tangutica Engl., Saxifraga przewalskii Engl. ex-Maxim., Saxifraga unguiculata Engl.) on the QXP, spanning time periods from the Last Glacial Maximum to 2080. Our results indicate that factors such as elevation, slope, mean annual temperature, isothermality, precipitation seasonality, and precipitation during the wettest quarter significantly affect species distribution patterns. Historical climate models demonstrate that approximately 30% of the QXP provided highly suitable habitat for Saxifragaceae species. Current projections suggest that this proportion has increased to over 30% and is anticipated to remain above 30% for the subsequent three-time intervals. Optimal habitats have been identified in southeastern QXP, western Sichuan, and northern Yunnan. The taxa are predicted to shift southward in response to future climate changes. Our findings underscore the importance of implementing conservation strategies that prioritize the establishment of protected areas in the southeastern QXP to safeguard these vulnerable Saxifragaceae species.

Climate change and human activities present substantial threats to the biodiversity of the Qinghai-Tibet Plateau (QTP), a region renowned for its rich endemic species. We aimed to examine genomic diversity and evolutionary trajectory of Achnatherum breviaristatum, a critically endangered monotypic grass genus endemic to the QTP. Diverging from its sister clade approximately 15 million years ago, A. breviaristatum stands in contrast to two widespread, ecologically dominant monotypic genera within the same clade—Neotrinia splendens and Psammochloa villosa—which thrive in arid northwestern China and neighboring regions. By analyzing high-quality chromosome-level genome assemblies and population resequencing data from all three species, we reveal that A. breviaristatum exhibits markedly low genetic diversity and heterozygosity. All species underwent parallel demographic declines since the Quaternary glaciation. During the Holocene, population sizes of all three species continued to diminish further, with A. breviaristatum ultimately becoming the smallest. The species’ current critically endangered status likely stems from its inability to reproduce clonally compared with two widespread relatives, coupled with Holocene vegetation shift and anthropogenic activities. Intriguingly, a significantly reduced genetic load in A. breviaristatum may have counteracted its low diversity, enabling provisional persistence on the QTP. This study highlights the interplay of historical climatic shifts, genetic constraints, and anthropogenic impacts in shaping the fate of endemic species, offering insights for conservation strategies in vulnerable ecosystems.

Ancient whole-genome duplication (WGD) or polyploidization is prevalent in plants and has played a crucial role in plant adaptation. However, the underlying genomic basis of ecological adaptation and subsequent diversification after WGD are still poorly understood in most plants. Here, we report a chromosome-scale reference genome assembly for the genus Orinus (Orinus kokonorica as representative) and preformed comparative genomics with its closely related genus Cleistogenes (Cleistogenes songorica as representative), both belonging to a newly named subtribe Orininae of the grass subfamily Chloridoideae. The two genera may share one paleo-allotetraploidy event before 10 million years ago, and their two subgenomes display neither fractionation bias nor global homoeolog expression dominance. Recent expansion of transposable elements and enormous contraction in gene families in O. kokonorica have maintained a similar genome size compared to C. songorica. Further comparative genomic analyses reveal substantial genome rearrangements and extensive structural variations (SVs) between the two species. With comparative transcriptomics, we demonstrate that functional innovations of orthologous genes have played an important role in promoting adaptive evolution and diversification of the two genera after polyploidization. In addition, copy number variations in flower and rhizome development related genes and extensive SVs between orthologs may contribute to the morphological differences between the two genera. Our results provide significant new insights into the adaptive evolution and subsequent diversification of the two genera after polyploidization.

We sought to generate a preliminary demographic framework for Psammochloa villosa to support of future studies of this ecologically important desert grass species, its conservation, and sustainable utilization. Psammochloa villosa occurs in the Inner Mongolian Plateau where it is frequently the dominant species and is involved in sand stabilization and wind breaking. Here, we characterized the genetic diversity and structure of 210 individuals from 43 natural populations of P. villosa using amplified fragment length polymorphism (AFLP) markers. We obtained 1728 well-defined amplified bands from eight pairs of primers, of which 1654 bands (95.72%) were polymorphic.All these values indicate that there is abundant genetic diversity, but limited gene flow in P. villosa. However, an analysis of molecular variance (AMOVA) showed that genetic variation mainly exists within 43 populations of the species (64.16%), and we found that the most genetically similar populations were often not geographically adjacent. Thus, this suggests that the mechanisms of gene flow are surprisingly complex in the species and may occur over long distances. In addition, we predicted the distribution dynamics of P. villosa based on the spatial distribution modeling and found that its range has contracted continuously since the last inter-glacial period. We speculate that dry, cold climates have been critical in determining the geographic distribution of P. villosa during the Quaternary period. Our study provides new insights into the population genetics and evolutionary history of P. villosa in the Inner Mongolian Plateau, which can be used to design in-situ conservation actions and to prioritize sustainable utilization of germplasm resources.