A comprehensive study of the genetic characteristics of endangered species is a prerequisite for their effective conservation and management. Rhododendron farinosum is an endangered ornamental species with extremely small populations located in northeastern Yunnan Province. To unravel the reasons behind the endangerment of this species and provide guidance for the rational conservation of this species, this study obtained a large number of SNP loci by using double-digest restriction-site-associated DNA sequencing (ddRAD-seq) to evaluate the genetic diversity and genetic structure of R. farinosum, as well as to infer the population history of this species. Our findings reveal that, at the population level, R. farinosum exhibited a high genetic diversity (π = 0.1948 ± 0.0020, H_E = 0.1880 ± 0.0020). The F_ST values (0.1383–0.2231) indicated high genetic differentiation among the three populations. The AMOVA revealed that 62.83% of the genetic variation originated within populations and 37.17% between populations. The PCA, Structure, and UPGMA consistently depicted that the three populations of R. farinosum are clearly distinguished into three clusters. Furthermore, the effective population size of R. farinosum was inferred to date back to 95,000 years ago using the stairway plot, with a continuous decline from 3292 years. Based on these findings, we propose conservation strategies and management measures for R. farinosum.

Sapindus delavayi is a drought-resistant tree species endemic to the dry–hot valleys of Southwestern China and is of great significance for soil and water conservation and ecological restoration. In this study, we sequenced the transcriptome of its leaves using the Illumina HiSeq 4000 platform and obtained 96.12 Gb of high-quality data (Q20 = 98.68%, Q30 = 95.62%), which were de novo assembled to obtain 89,228 unigenes (N50 = 1538 bp), of which 63,005 (70.61%) were successfully annotated to at least one database (NR, NT, SwissProt, KOG, KEGG, GO, Pfam). Overall, 53.96% of the unigenes in the S. delavayi leaves were annotated to Acer yangbiense, which belongs to the same family as S. delavayi. A total of 42,870 CDSs and 21,488 SSR loci were detected, with the highest mononucleotide repeat rate at 42.72% of the total number. Drought stress experiments identified 669–1203 differentially expressed genes (DEGs). Through our research, the first high-quality transcriptome database of S. delavayi has been constructed and its drought-resistance-related gene features have been analyzed, laying an important foundation for future functional gene mining, molecular marker development, molecular diversity studies, molecular breeding, and ecological adaptation research.