Chinese chestnut (Castanea mollissima Blume) can be infested by Dryocosmus kuriphilus Yasumatsu, resulting in gall formation and yield losses. Research on the control of gall wasps using genomics approaches is rarely reported. We used RNA-seq to investigate the dynamic changes in the genes of a chestnut species (C. mollissima B.) during four gall-formation stages caused by D. kuriphilus. A total of 21,306 genes were annotated by BLAST in databases. Transcriptome comparison between different gall-formation stages revealed many genes that were differentially expressed compared to the control. Among these, 2410, 7373, 6294, and 9412 genes were differentially expressed in four gall-formation stages: initiation stage (A), early growth stage (B), late growth stage (C), and maturation stage (D), respectively. Annotation analysis indicated that many metabolic processes (e.g., phenylpropanoid biosynthesis, secondary metabolism, plant–pathogen interaction) were affected. Interesting genes encoding putative components of signal transduction, stress response, and transcription factors were also differentially regulated. These genes might play important roles in response to D. kuriphilus gall formation. These new data on the mechanism by which D. kuriphilus infests chestnuts could help improve chestnut resistance.

Chinese Chestnut (Castanea mollissima) is an economically valuable tree in China. More than 300 wild and cultivated varieties were reported. In this study, we reported and characterized the complete chloroplast genome sequence of Chinese Chestnut cultivar ‘Hongli’, variant dominant strain with high yield, good quality of nuts, especially with red coloration in their leaves, twigs, and involucres of fruits. The chloroplast genome was determined to be 160,871 bp in length. It contained large single-copy (LSC) and small single-copy (SSC) regions of 90,498 and 18,971 bp, respectively, which were separated by a pair of 25,701 bp inverted repeat (IR) regions. The genome is predicted to contain 130 genes, including 83 protein-coding genes, 37 tRNA genes, 8 rRNA genes, and 2 pseudo genes. The overall GC content of the genome is 36.7%. A phylogenetic tree reconstructed by 25 chloroplast genomes reveals that C. mollissima 'Hongli' is most closely related to wild C. mollissima that was collected from China.