Diversity of Diaporthe species associated with melanose disease on citrus trees in Jiangxi Province, China

Citrus melanose is an important disease that seriously damages citrus production. It is caused by Diaporthe species, which are known as important pathogens, endophytes or saprobes with broad host ranges. Over 170 species of Diaporthe were reported around the world and the complexity of species structures makes it hard to be identified. Phylogenetic analysis based on translation elongation factor 1-ɑ ( TEF1 ) gene, ß-tubulin ( TUB ) gene, calmodulin ( CaM ) gene, histone ( HIS ) gene and ITS locus was a reliable method to identify Diaporthe species In this study, the species structure of Diaporthe species from different tissues within individual trees was investigated. Altogether, 494 single spore isolates were obtained, and 92 of them were selected to sequence the five loci (ITS, TEF1 , HIS , TUB , CaM ) for phylogenetic analysis. Based on the combined multi-locus dataset, phylogenetic trees constructed by using two methods (MP and ML) showed that D. citri was the dominant species no matter on fruits, leaves or twigs. Diaporthe species showed the greatest diversity on fruits and the least diversity on twigs. D. eres was only isolated from twigs. The results of this study may enhance our understanding for the species diversity of Diaporthe species on different tissues from same trees, such information would be useful for the control of Diaporthe diseases in the future.