Leptosphaerulina species isolated from golf turfgrass in China, with description of L. macrospora, sp. nov.

ABSTRACT

Leptosphaerulina leaf blight occurs on most turfgrasses. Hitherto, Leptosphaerulina species associated with this disease include L. americana, L. argentinensis, L. australis, and L. trifolii. However, following Koch’s postulates, L. australis was confirmed as saprobes but not pathogens, and the other three species have not been tested. The pathogenicity of Leptosphaerulina spp. is still questionable. In this study, we isolated 19 Leptosphaerulina strains from diseased golf turfgrasses in China, and they were identified as L. gaeumannii, L. saccharicola, and a new species, L. macrospora, through multilocus (ITS, 28S, rpb2, and tub2) phylogenetic analyses and morphological observations. Pathogenicity test revealed that the three Leptosphaerulina species identified in this study cannot infect live/healthy turfgrass tissues of Poa pratensis and Agrostis stolonifera and only produced pseudothecia on the dead leaves of stressed seedlings. Considering the results of pathogenicity tests in this and previous studies, we speculate that most Leptosphaerulina species isolated from diseased turfgrass are not pathogens but saprobes. Applying proper management practices to prevent severe turfgrass stress is a key measure to reduce or eliminate the effects of Leptosphaerulina on golf turfgrass.

KEYWORDS:

• High temperature stress
• Leptosphaerulina leaf blight
• multilocus phylogeny
• pathogenicity test
• turfgrass disease
• 1 new taxon

ACKNOWLEDGMENTS

The authors are grateful to G. Q. Huang, golf course maintenance (GCM) manager of Longxishunjing Golf Club, and Z. W. Cao, GCM manager of Changyang Golf Club, for their assistance in sample collection. In addition, the authors would also like to thank L. Zhu and H. Z. Geng, GCM managers of Olympic Golf Club, for supplying healthy turfgrass seedlings for pathogenicity test.

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Additional information

Funding

This study was financially supported by the National Natural Science Foundation of China (no. 31750001) and Frontier Key Program of Chinese Academy of Sciences (no. QYZDY-SSW-SMC029).