Extensive range of deserts and gobis (rocks) had promoted habitat fragmentation of species in arid northwestern China. Distribution of endangered Gymnocarpos przewalskii Maxim. covers most of gobis (rocks) and desert terrain across arid regions of northwestern China. In the present study, we had employed genomic phylogeographical analysis to investigate population structure of G. przewalskii and test the effect of environmental conditions on spatial pattern of genetic diversity. Results showed four groups were identified from east to west: Edge of the Alxa Desert, Hexi Corridor, Hami Basin, and North edge of the Tarim Basin. Genetic diversity was at an equal level among four groups. General linear model (GLM) analysis showed spatial pattern of genetic diversity was significant correlated with three habitat variables including habitat suitability at present (N_pre) and last glacial maximum (LGM) (N_LGM) periods, and locality habitat stability (N_Stab). It concluded that habitat fragmentation had triggered lineage divergences of G. przewalskii in response to long-term aridification. Genome-wide single nucleotide polymorphisms (SNPs) could increase the ability of clarifying population structures in comparison with traditional molecular markers. Spatial pattern of genetic diversity was determined by fragmented habitats with high habitat suitability (N_pre and N_LGM) and stability (N_Stab). At last, we propose to establish four conservation units which are in consistent with the population grouping to maintain the genetic integrity of this endangered species.

Northwestern China has a wealth of endemic species, which has been hypothesized to be affected by the complex paleoclimatic and paleogeographic history during Quaternary. In this paper, we used Gymnocarpos przewalskii as a model to address the evolutionary history and current population genetic structure of species in northwestern China. We employed two chloroplast DNA fragments (rps16 and psbB‐psbI), one nuclear DNA fragment (ITS), and simple sequence repeat (SSRs) to investigate the spatial genetic pattern of G. przewalskii. High genetic diversity (cpDNA: h_S = 0.330, h_T = 0.866; ITS: h_S = 0.458, h_T = 0.872) was identified in almost all populations, and most of the population have private haplotypes. Moreover, multimodal mismatch distributions were observed and estimates of Tajima's D and Fu's FS tests did not identify significantly departures from neutrality, indicating that recent expansion of G. przewalskii was rejected. Thus, we inferred that G. przewalskii survived generally in northwestern China during the Pleistocene. All data together support the genotypes of G. przewalskii into three groups, consistent with their respective geographical distributions in the western regions—Tarim Basin, the central regions—Hami Basin and Hexi Corridor, and the eastern regions—Alxa Desert and Wulate Prairie. Divergence among most lineages of G. przewalskii occurred in the Pleistocene, and the range of potential distributions is associated with glacial cycles. We concluded that climate oscillation during Pleistocene significantly affected the distribution of the species.

Sugar allocation between vegetative and reproductive tissues is vital to plant development, and sugar transporters play fundamental roles in this process. Although several transcription factors have been identified that control their transcription levels, the way in which the expression of sugar transporter genes is controlled at the posttranscriptional level is unknown. In this study, we showed that OsRRM, an RNA-binding protein, modulates sugar allocation in tissues on the source-to-sink route. The OsRRM expression pattern partly resembles that of several sugar transporter and transcription factor genes that specifically affect sugar transporter gene expression. The messenger RNA levels of almost all of the sugar transporter genes are severely reduced in the osrrm mutant, and this alters sugar metabolism and sugar signaling, which further affects plant height, flowering time, seed size, and starch synthesis. We further showed that OsRRM binds directly to messenger RNAs encoded by sugar transporter genes and thus may stabilize their transcripts. Therefore, we have uncovered the physiological function of OsRRM, which sheds new light on sugar metabolism and sugar signaling.

This study presents the first record of the overall distribution of the seagrass Halophila beccarii Ascherson on the island of Hainan. Statistical and ecological methods were used to analyze the distribution of the species and the influence of environmental factors. Halophila beccarii was mainly distributed in the northwest and southeast of Hainan, in lagoons with a total area of 20.981 km², including the largest H. beccarii area in China covering approximately 9.58 km² in Xiaohai, Wanning; there were also 4.89 km² in Xinying Bay, Danzhou, approximately 2.20 km² in Huachang Bay, Chengmai, 1.88 km² in Dongzhai Port, Haikou, 0.95 km² in Xinying Port, Lingao, approximately 0.668 km² in Laoyehai, Wanning, approximately 0.363 km² in Hongpai, approximately 0.23 km² in Maniao, and approximately 0.22 km² in Huanglong Port, Lingao. The average coverage of H. beccarii measured at 7.08–56.33%, the density of stem and branch was 487.47–20,167.1 ind/m², and the biomass measured at 1.57–112.94 gDW/m². The growth distribution was mainly influenced by habitat type and, to a lesser extent, by tidal branching channels, heavy metal content (Cu, Pb, Cr, Zn) in the marine environment, and human activities in adjacent coastal areas.