First Report of Top Blight of Cunninghamia lanceolata Caused by Diaporthe unshiuensis and Diaporthe hongkongensis in China

Four Unrecorded Species of Endophytic Diaporthe (Sordariomycetes) in Korea

Endophytic fungi associated with four plant species in Korea were isolated and characterized using morphological and molecular analyses. Phylogenetic analyses of the internal transcribed spacer (ITS) region, β-tubulin (TUB) gene, and translation elongation factor 1-α (EF1-α) gene revealed four previously unrecorded species of Diaporthe in Korea: D. caryae, D. phoenicicola, D. stewartii, and D. unshiuensis. Detailed descriptions of colony morphology and conidial characteristics are provided for each species. This study expands our knowledge of the diversity and distribution of endophytic Diaporthe in Korea and highlights the importance of these fungi in the ecosystem.

Morphological and phylogenetic analyses reveal three new species of Fusarium (Hypocreales, Nectriaceae) associated with leaf blight on Cunninghamialanceolata in China

Chinese fir (Cunninghamialanceolata) is a special fast-growing commercial tree species in China with high economic value. In recent years, leaf blight disease on C.lanceolata has been observed frequently. The diversity of Fusarium species associated with leaf blight on C.lanceolata in China (Fujian, Guangxi, Guizhou, and Hunan provinces) was evaluated using morphological study and molecular multi-locus analyses based on RNA polymerase second largest subunit (RPB2), translation elongation factor 1-alpha (TEF-1α), and RNA polymerase largest subunit (RPB1) genes/region as well as the pairwise homoplasy index tests. A total of five Fusarium species belonging to four Fusarium species complexes were recognized in this study. Two known species including Fusariumconcentricum and F.fujikuroi belonged to the F.fujikuroi species complex, and three new Fusarium species were described, i.e., F.fujianense belonged to the F.lateritium species complex, F.guizhouense belonged to the F.sambucinum species complex, and F.hunanense belonged to the F.solani species complex. To prove Koch's postulates, pathogenicity tests on C.lanceolata revealed a wide variation in pathogenicity and aggressiveness among the species, of which F.hunanense HN33-8-2 caused the most severe symptoms and F.fujianense LC14 led to the least severe symptoms. To our knowledge, this study also represented the first report of F.concentricum, F.fujianense, F.fujikuroi, F.guizhouense, and F.hunanense causing leaf blight on C.lanceolata in China.

Molecular Identification and Pathogenicity of Diaporthe eres and D. hongkongensis (Diaporthales, Ascomycota) Associated with Cherry Trunk Diseases in China

This study aimed to identify fungal species associated with trunk diseases of sweet cherries (Prunus avium) in several commercial cherry orchards in Beijing, Guizhou and Shandong provinces, China. In total, eighteen fungal strains that fitted well into the species concept of Diaporthe were isolated. Based on both morphological and multi-locus phylogenetic analyses of internal transcribed spacer region (ITS), beta-tubulin (tub-2), calmodulin (Cal) and translation elongation factor 1-α (tef1-α) sequencing data, fourteen isolates were identified as Diaporthe eres, while four isolates were classified as D. hongkongensis. Here, we report D. hongkongensis causing sweet cherry branch dieback disease and, further, we confirmed the host association of D. eres with sweet cherries in China. A pathogenicity assay revealed the ability of both D. eres and D. hongkongensis to cause shoot necrosis and stem lesions on Prunus avium cv. 'Brooks' (mean lesion lengths of 1.86 cm and 1.56 cm, respectively). The optimal temperature for the growth of both Diaporthe species was tested. The optimal growth temperature for D. hongkongensis was 30 °C, and the 25-28 °C temperatures were the most favorable for the growth of D. eres strains. This research advances the understanding of fungal trunk diseases in fruit crops, particularly gummosis and branch dieback disease in Chinese cherry orchards, and will aid growers in making decisions about cultural practices and disease management.