Hippophae gyantsensis Lian is a pioneering tree species in Chinese forestry ecological engineering, known for its robust stress tolerance, water retention capacity, and soil improvement qualities. However, the lack of rapid nursery technology has been a significant impediment to the development of the H. gyantsensis industry. In the present study, we have successfully established a tissue culture regeneration system for H. gyantsensis. The most effective methods for seed disinfection, ensuring sterility in seedlings, were found to be 75% alcohol disinfection for 40 s and 10% sodium hypochlorite disinfection for 10 min. The best media tested for callus induction in cotyledons and hypocotyls of sterile seedlings were 1/3 MS + 0.5 mg/L KT + 0.75 mg/L NAA and 1/3 MS + 0.3 mg/L 6-BA + 1.5 mg/L IBA, respectively. As the explants, cotyledons yielded larger calli with a greater size and differentiation ability than hypocotyls. For the induction of indeterminate shoots and proliferation, the most suitable media were 1/3 MS + 0.5 mg/L IAA + 0.75 mg/L 6-BA and 1/3 MS + 1.0 mg/L 6-BA + 0.05 mg/L IBA + 0.1 mg/L KT, respectively. Lastly, the best worked rooting formulation was 1/4 MS + 0.3 mg/L IBA. This study marks a significant milestone in the establishment of a systematic tissue culture regeneration system for H. gyantsensis, which will facilitate the industrial rapid propagation of high-quality seedlings and provide the foundation for improvement through genetic transformation.

The Plateau Hongliu (Myricaria elegans Royle.) is a woody shrub halophyte that thrives in arid areas of western Tibet, in the Himalayan Mountains. It is acclaimed as superior in saline stress acclimation and as a critical pharmaceutical resource of the Tibetan traditional herb. Nevertheless, the mitogenome in the genus Myricaria remains unknown. Here, using the Illumina and PacBio sequencing assays, the first complete mitogenome of the M. elegans revealed a multi-branched skeleton with a total length of 416,354 bp and GC content of 44.33%, comprising two circular molecules (M1 and 2). The complete mitogenome annotates 31 unique protein-encoding genes (PEGs), fifteen tRNAs, and three rRNA genes. The UAA exhibits the most prominent codon usage preference as a termination, followed by UUA codons for leucine. The mitogenome contains 99 simple sequence repeats and 353 pairs of dispersed repeats, displaying the most frequent in palindromic repeats. Gene transfer analyses identified 8438 bp of 18 homologous fragments from the plastome, accounting for 2.03% of the total length. Using the PREP suite, 350 C-U RNA editing sites were predicted, of which nad4 and ccmB were on the top frequency. Syntenic and phylogenetic analyses suggested weakly conserved patterns of M. elegans in Caryophyllales owing to the genome rearrangement. In summary, the deciphered unique features and complexities of the mitogenome in M. elegans provide novel insights into understanding the evolution and biological conservation underlying climate resilience in halophytes.

The accurate and efficient extraction of individual tree phenotypic traits for seabuckthorn (Hippophae rhamnoides L.) in natural forests is crucial for germplasm exploration, precision silviculture, and ecological restoration. This study extracted structural and biochemical traits of seabuckthorn in Tibet’s Lhasa valley using Unmanned aerial vehicle (UAV) LiDAR, multispectral imagery, and the N-PROSAIL model. Firstly, building on a classification conducted through multi-scale spatial analysis and hierarchical clustering with dynamic thresholds, shrub interference was effectively reduced, thereby improving the accuracy of individual tree segmentation. Tree height and crown width were derived from the segmentation results, and a DBH estimation model was developed using handheld LiDAR data. Finally, leaf nitrogen content was mapped within canopies using random forest combined with the N-PROSAIL model and nitrogen reference data. The results demonstrated that the optimized segmentation method successfully extracted structural traits (F1 = 84.21%). Tree height was accurately estimated (R² = 0.814, RMSE = 0.580 m), and the DBH prediction model performed satisfactorily (R² = 0.779, RMSE = 1.725 cm). The random forest model also effectively estimated leaf nitrogen content (R² = 0.680, RMSE = 2.074 mg/g).

Hippophae gyantsensis Lian is an important native tree species in the “One River, Two Streams” valley of Tibet, valued for its ecological restoration potential and nutrient-rich fruits. However, this species has several limitations, including a long fruiting cycle (3–5 years to flowering and 10–15 years to reach peak fruit production), small fruit size, and numerous branch thorns. These traits hinder large-scale cultivation and mechanized harvesting, creating an urgent need for improved varieties with larger fruit and higher yield. In this study, we established an efficient Agrobacterium-mediated genetic transformation system for H. gyantsensis using hypocotyls as explants. Under optimized conditions (OD₆₀₀ = 0.5, AS = 200 μmol/L, infection time = 15 min), the transformation efficiency reached 36.67% (calculated as the number of PCR-positive plants divided by the total number of explants initially inoculated with Agrobacterium). A rooting rate of 12.5% was achieved using 100 mg/L rooting powder (ABT1) for 40 min, resulting in an overall success rate of approximately 4–5%. Furthermore, we identified and cloned two fruit-size-related genes, Hgfw2.2 and Hgfw3.2, from H. gyantsensis. Heterologous expression of Hgfw2.2 and Hgfw3.2 in tomato decreased and increased fruit size, respectively, consistent with their regulatory roles in fruit development. Given the positive regulatory effect of Hgfw3.2, this gene was further transformed into H. gyantsensis. This study represents the first report of a stable genetic transformation platform for H. gyantsensis, providing a robust technical foundation for future molecular breeding and the development of improved, large-fruited varieties.