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The dove tree (Davidia involucrata Baill.), a tertiary relic species, is adapted to cool climates. With the progression of global warming, high-temperature stress has become the primary environmental factor restricting geographic distribution, ex situ conservation, and landscape application for D. involucrata resources. However, the detailed molecular events underlying D. involucrata responses to heat stress are poorly understood. Here, we conducted RNA-Seq-based gene expression profiling in D. involucrata seedlings during the time course of a 42 &deg, C heat treatment (0, 1, 6, and 12 h). After de novo assembly, we obtained 138,923 unigenes, of which 69,743 were annotated in public databases. Furthermore, 19,532, 20,497 and 27,716 differentially expressed genes (DEGs) were identified after 1 h (HS1), 6 h (HS6), and 12 h (HS12) of heat treatment in comparison to 0 h (HS0), respectively. Based on a KEGG enrichment analysis, the two pathways &ldquo, protein processing in endoplasmic reticulum&rdquo, and &ldquo, plant hormone signal transduction&rdquo, are hypothesized to play vital roles during heat response in D. involucrata, and their potential interactions during heat stress are also discussed. In addition, 32 genes encoding putative heat shock transcription factors (Hsfs) were found to be associated with the response of D. involucrata to heat stress. Finally, the expression patterns of eight heat-responsive genes derived from qRT-PCR were in agreement with their transcript level alterations, as determined by a transcriptome analysis. Taken together, our transcriptomic data provide the first comprehensive transcriptional profile affected by heat stress in D. involucrata, which will facilitate further studies on the improvement of heat tolerance in this rare and endangered species.

Davidia involucrata Baill (in Nyssaceae family) is a relic species of tertiary paleo tropical relic in China. It belongs to class I of the national key protected endangered plant. Recently, there are signs of large-scale death. This study investigated the population of Davidia involucrata Baill in the Mount Fanjing Nature Reserve and used field sampling and laboratory analysis to systematically study the stoichiometric characteristics of C, N and P in the plants and the soil and their driving factors. The results indicate that the average contents of organic carbon, total nitrogen, total phosphorus, hydrolysable nitrogen and available phosphorous in soils from Davidia involucrata Baill lands were 24.06 g kg−1, 2.22 g kg−1, 4.94 g kg−1, 168.84 mg kg−1 and 58.30 mg kg−1, respectively. The total nitrogen, sodium and zinc contents and the physical and chemical soil characteristics were positively correlated with the C, N and P contents in the leaves of Davidia involucrata Baill. The available phosphorous, magnesium, total phosphorous and available potassium in the soil were positively correlated with the C and N contents in the stems of Davidia involucrata Baill. The growth of Davidia involucrata Baill is substantially limited by organic C. We hope this study could provide some theoretical basis for scientific and effective protection of Davidia involucrata in Fanjing Mountain.