Transcriptional Analysis ofColletotrichum fructicolafrom Different Geographic Regions Inoculated toCamellia oleifera

Anthracnose, caused by Colletotrichum. Spp., is an important disease affecting oil tea ( Camellia oleifera ). Extensive molecular studies have demonstrated that Colletotrichum fructicola is the dominant pathogen of oil tea anthracnose in China. The study aims to investigate differences in molecular processes and regulatory genes at different stages of infection of C. fructicola , to aide in understanding differences in pathogenic mechanisms of C. fructicola of different geographic populations. Materials and Methods: We compared the pathogenicity of C. fructicola from different populations (Wuzhishan, Hainan province and Shaoyang, Hunan province), and gene expression of representative strains of the two populations before and after inoculation in oil tea using RNA sequencing. In results we found that C. fructicola from Wuzhishan has a stronger ability to infect and impact oil tea leaf tissue. Up-regulated genes in oil tea following infection with the two geographic populations were associated with a number of ribosome-related GO terms and ribosome metabolic related KEGG pathways, and were significantly enriched in galactosidase activity, glutamine family amino acid metabolism, arginine and proline metabolism. In addition, up-regulated gene lists associated with infection in the Wuzhishan strains were significantly enriched purine metabolism pathways as well, while Shaoyang strains were not significantly enriched in these processes. Differences in gene expression were indicative of greater active transcription and translation in the Wuzhishan population while more active glycoprotein metabolism was observed following inoculation with strains from Shaoyang. These results indicate that C. fructicola obtained sugars and amino acids from oil tea tissue to resist host immune pressure. Moreover, more active in transcriptional and translational activity and the greater regulation of purine metabolism pathway in the Wuzhishan strain might contribute to its stronger pathogenicity.