The antioxidant enzyme system is the main defense system responsible for maintaining cellular reactive oxygen species (ROS) homeostasis and normal plant growth and development after saline stress. In this study, we identified and characterized the members of the SOD, APX and CAT gene families of the antioxidant enzyme system in Gymnocarpos przewalskii, using plant physiology and molecular biology methods, and analyzed the pattern of enzyme activity in response to NaCl stress. It was found that seven, six and two genes of SOD, APX and CAT gene families, respectively, were expressed in the leaf tissue of G. przewalskii, in which most of the genes were significantly upregulated under NaCl stress, and the enzymatic activities were in accordance with the gene expression. Three positive selection sites in the GpCAT1 gene can increase the hydrophilicity of the GpCAT1 protein, increase the volume of the active site and increase the affinity for H₂O₂, thus improving the catalytic efficiency of GpCAT1. The results of the present study provide new insights for further investigations of the evolution and function of the SOD, APX and CAT gene families in G. przewalskii and their essential roles under salt stress, and the findings will be useful for revealing the molecular mechanism of salt tolerance and breeding of salt-tolerant plants.

As climate change continues to alter species distributions, Pinus bungeana, an endangered conifer of significant ecological and ornamental value, faces heightened vulnerability, underscoring the critical need to understand and predict its future habitat shifts. Here, we used 83 effective geographic distribution records, along with climate, topography, soil, and drought indices, to simulate the potential distribution of suitable ecological niches for P. bungeana under current conditions and across three future time periods (2040–2060, 2060–2080, and 2080–2100) under two shared socioeconomic pathways: SSP126 (low emissions) and SSP585 (high emissions), using the maximum entropy (MaxEnt) model. The results show that the area under the receiver operating characteristic curve (AUC) for all simulations exceeded 0.973, indicating high predictive accuracy. Soil moisture, the minimum temperature of the coldest month, temperature seasonality, isothermality, the precipitation of the wettest quarter, and altitude were identified as key environmental factors limiting the distribution of P. bungeana, with soil moisture and the minimum temperature of the coldest month being the most important factors. Under the current climatic conditions, the potentially suitable ecological niches for P. bungeana were primarily located in Shaanxi Province, southern Shanxi Province, southeastern Gansu Province, northeastern Sichuan Province, Henan Province, and northwestern Hubei Province, covering approximately 75.59 × 10⁴ km². However, under the future climate scenarios, highly suitable areas were projected to contract, with the rate of decline varying significantly between scenarios. Despite this, the total area of potentially suitable ecological niches was predicted to expand in the future periods. Additionally, a pronounced eastward shift in P. bungeana’s distribution was projected, especially under the high-emission SSP585 scenario. These findings provide insights into the potential impacts of climate change on the distribution of P. bungeana, and they offer valuable guidance for its conservation strategies and habitat management in the context of climate change.

Nitrogen assimilation plays a critical role in the response of plants to salt stress. In this study, bioinformatics and computational biology methods were employed to identify members of the Lycium GS, GOGAT, and GDH gene families, and analyzed their expression patterns and transcriptional regulatory networks under salt stress in black wolfberry (Lycium ruthenicum). In addition, the adaptive evolutionary mechanisms of the black wolfberry Fd-GOGAT gene were explored. The results showed that the genomes or transcriptomes of Lycium species contain two to four GS genes, two GOGAT genes, and three to four GDH genes. Following NaCl stress, the expression of Fd-GOGAT and NADH-GOGAT in the leaves of black wolfberry was downregulated with increasing time and NaCl concentration; in the roots, Fd-GOGAT and NADH-GOGAT were upregulated by 1.79-fold and 1.40-fold, respectively, 12 h after severe NaCl stress. GS2 and GS1.1 are highly expressed in leaves and roots, respectively, and their expression is significantly upregulated under NaCl stress. The expression of GDH in leaves is downregulated under salt stress, whereas in roots, the expression of NADP-GDH and GDH2 is upregulated under NaCl stress. C2H2-63, a key transcription factor regulating nitrogen assimilation in black wolfberry under salt stress, is likely to promote nitrogen assimilation through its upregulated expression. Additionally, seven positively selected sites (p.Glu220, p.Ala388, p.Ala880, p.Ser921, p.Leu1319, p.Ser1350, and p.Ser1570) were found in the Fd-GOGAT protein of black wolfberry. Compared to Ningxia wolfberry (L. barbarum), these mutation sites enhance the affinity of Fd-GOGAT for its substrate Glu, which helps to increase the catalytic efficiency of Fd-GOGAT in black wolfberry under salt stress. In conclusion, the adaptation of salt stress-related nitrogen assimilation genes in black wolfberry involves both gene expression regulation and adaptive evolution. Enhancing the GS/GOGAT pathway under salt stress is a primary strategic choice for nitrogen assimilation in black wolfberry.