Transcriptome of Pterospermum kingtungense provides implications on the mechanism underlying its rapid vegetative growth and limestone adaption.

Pterospermum kingtungense C.Y.Wu ex Hsue is a typical tree species living in the relatively adverse limestone habitat. Due to its excellent wood quality and big size, it is an important timber resource which caused its endangered. We firstly provide the data resources by reporting an annotated transcriptome assembly. 203 million unique Illumina RNA-seq reads were produced with totally 50,333 transcripts, among which 48,778 transcripts were annotated. By a global comparison of homology between P. kingtungense and cacao, we identified 9,507 single copy orthologues and 990 P. kingtungense specific genes. GO enrichment analyses indicate that P. kingtungense specific genes are enriched in defense response, implying potential adaptation to limestone environment. As to cell compartment, the genes are enriched in thylakoid component. Consistently, KEGG enrichment indicates that genes are enriched in photosynthesis. In addition, we identified two genes under positive selection in P. kingtungense species. These results suggest that P. kingtungense have strong photosynthetic capacity, which related to vegetation growth. Our work provides the genomic resources of a limestone specific tree with economic importance to local society and suggests possible mechanism on its characteristics on the limestone adaption and excellent wood properties, which will be important for its conservation and sustainable utilization.