Transcriptome Analysis of Hong Yang Kiwifruit in Response to Bactrocera dorsalis (Diptera: Tephritidae) Larval Feeding

Abstract The Oriental fruit fly, Bactrocera dorsalis (Hendel) (Diptera: Tephritidae), is a major pest of Hong Yang kiwifruit (Actinidia chinensis Planch cv. chinensis) grown in China. Our transcriptome analysis of the interaction between Hong Yang kiwifruit and B. dorsalis revealed numerous changes in gene expression level attributable to Oriental fruit fly feeding, resulting in the down-regulation of 112 genes and the up-regulation of 226 genes. Gene ontology analysis revealed that differential expression genes (DEGs) were mainly involved in biological processes (4,568; 56.28%), molecular function (2,297; 28.30%), and cellular components (1,251; 15.41%). By searching against the Kyoto Encyclopedia of Genes and Genomes Pathway database (KEGG), 258 DEGs were assigned to 51 KEGG pathways belonging to five main categories: metabolism (239, 92.64%), genetic information processing (10, 3.88%), organismal systems (5, 1.94%), cellular processes (3, 1.16%), and environmental information processing (1, 0.39%). The numbers of DEGs up-regulated were much higher than those down-regulated. Expression of genes involved in the secondary metabolism was detected, and several key genes showed differential expression. Our results suggest that B. dorsalis induced defense response of Hong Yang kiwifruit, including hypersensitive response and immunity triggered by either pathogen/microbe-associated molecular patterns or immunity effectors. Metabolic process was also adjusted to adapt to these responses. Our results provide extensive transcriptome information for A. chinensis and valuable clues for elucidating the mechanism of interaction between Hong Yang kiwifruit and B. dorsalis, and will facilitate molecular breeding for Actinidia crop plants.