First Report of Summer Patch of Kentucky Bluegrass Caused by Magnaporthe poae in China

Abstract

HomePlant DiseaseVol. 101, No. 1First Report of Summer Patch of Kentucky Bluegrass Caused by Magnaporthe poae in China PreviousNext DISEASE NOTES OPENOpen Access licenseFirst Report of Summer Patch of Kentucky Bluegrass Caused by Magnaporthe poae in ChinaQ. Y. Liu, M. H. Liu, T. Li, J. H. Chen, F. G. Zhang, and J. HuQ. Y. LiuSearch for more papers by this author, M. H. LiuSearch for more papers by this author, T. LiSearch for more papers by this author, J. H. ChenSearch for more papers by this author, F. G. ZhangSearch for more papers by this author, and J. HuSearch for more papers by this authorAffiliationsAuthors and Affiliations Q. Y. Liu M. H. Liu T. Li J. H. Chen F. G. Zhang J. Hu , College of Agro-grassland Science, Nanjing Agricultural University, Nanjing 210095, China. Published Online:24 Oct 2016https://doi.org/10.1094/PDIS-05-16-0732-PDNAboutSections ToolsAdd to favoritesDownload CitationsTrack Citations ShareShare onFacebookTwitterLinked InRedditEmailWechat Magnaporthe poae Landschoot & Jackson, the causal agent of summer patch on Kentucky bluegrass (Poa pratensis L.), creeping bentgrass (Agrostis stolonifera L.) and annual bluegrass (P. annua L.) has been reported in North America (Bassoriello and Jordan 2012; Swift et al. 2007; Tredway 2005); however, it has not been confirmed on turfgrass in China. In July 2015, over 40 turf samples exhibiting symptoms of tan irregular patches of dead turf ranging from 20 to 50 cm in diameter and discolored roots were collected from four golf courses in Beijing. Sections of root tissue with dark tips were surface sterilized in 0.6% sodium hypochlorite (NaClO) for 5 min, air dried for 1 min, and placed on potato dextrose agar (PDA) containing 50 mg liter–1 ampicillin and streptomycin sulfate. Plates were sealed with Parafilm and incubated in the dark at 25°C for 2 to 4 days, at which point a hyphal tip was cut and transferred to a new PDA plate and incubated at 25°C for another 7 days. A total of 28 isolates with morphology identical to M. poae were consistently recovered (Clarke and Gould 1993). Two isolates (FH-2, YQH-5) representing two golf courses were selected for molecular identification. DNA was extracted from mycelium using a DNAsecure Plant kit (Tiangen Biotech, China). The nuclear ribosomal internal transcribed spacer (ITS) region was amplified using primers ITS 4 and ITS 5 (White et al. 1990). PCR products were sequenced and BLAST analysis showed 99% similarity to M. poae in the GenBank database. Sequences have been deposited as accessions KX256158 and KX256159. To complete Koch’s postulates, sterile soil was put into six plastic pots (15 cm height × 15 cm top diameter × 10 cm bottom diameter, three replicates for each isolate), and 25 mg M. poae-infested Kentucky bluegrass seed was added and then covered by healthy Kentucky bluegrass core samples that were collected from a sward grown on sterile soil in a plastic container (50 cm length × 30 cm width × 30 cm height) at the turfgrass center in Nanjing Agricultural University. Pots were placed in a growth chamber with a 12-h day/night cycle at 30/25°C and 90% relative humidity. Disease symptoms were noted 2 to 3 weeks after inoculation. Isolations from symptomatic root samples on PDA produced fungal colonies with morphology consistent with M. poae. To our knowledge, this is the first confirmed report of summer patch on Kentucky bluegrass caused by M. poae in China. Its confirmation is a critical step toward developing disease management strategies for turfgrass in China.