First Report of Phytopythium Helicoides Causing Root and Crown Rot on Strawberry in China

HomePlant DiseaseVol. 104, No. 9First Report of Phytopythium helicoides Causing Root and Crown Rot on Strawberry in China PreviousNext DISEASE NOTES OPENOpen Access licenseFirst Report of Phytopythium helicoides Causing Root and Crown Rot on Strawberry in ChinaY. J. Zhan, W. J. Peng, Z. Q. Xu, H. Xu, and X. H. FengY. J. ZhanNanjing Tech University, College of Food Science and Light Industry, State Key Laboratory of Materials-Oriented Chemical Engineering, Nanjing 211816, ChinaSearch for more papers by this author, W. J. PengNanjing Tech University, College of Food Science and Light Industry, State Key Laboratory of Materials-Oriented Chemical Engineering, Nanjing 211816, ChinaSearch for more papers by this author, Z. Q. XuNanjing Tech University, College of Food Science and Light Industry, State Key Laboratory of Materials-Oriented Chemical Engineering, Nanjing 211816, ChinaSearch for more papers by this author, H. Xu†Corresponding author: H. Xu; E-mail Address: xuh@njtech.edu.cnhttp://orcid.org/0000-0002-9085-9542Nanjing Tech University, College of Food Science and Light Industry, State Key Laboratory of Materials-Oriented Chemical Engineering, Nanjing 211816, ChinaSearch for more papers by this author, and X. H. FengNanjing Shineking Biotech Co., Ltd., Nanjing 210061, ChinaSearch for more papers by this author AffiliationsAuthors and Affiliations Y. J. Zhan1 W. J. Peng1 Z. Q. Xu1 H. Xu1 † X. H. Feng2 1Nanjing Tech University, College of Food Science and Light Industry, State Key Laboratory of Materials-Oriented Chemical Engineering, Nanjing 211816, China 2Nanjing Shineking Biotech Co., Ltd., Nanjing 210061, China Published Online:8 Jul 2020https://doi.org/10.1094/PDIS-03-20-0550-PDNAboutSectionsSupplemental ToolsAdd to favoritesDownload CitationsTrack Citations ShareShare onFacebookTwitterLinked InRedditEmailWechat Strawberry (Fragaria × ananassa Duch.) is an important cash crop in China. According to the 2016 China Agricultural Yearbook, Jiangsu Province is an important player in China’s strawberry market, with a cultivation area of 18,100 ha and production of 460,000 metric tons per year. We investigated a commercial field in the Jiangsu Province where the strawberry cultivar HongYan had been cultivated for more than 5 years. Between September and December 2017, symptoms of root and crown rot appeared in strawberry plants: plants developed disease symptoms characterized by yellowing of lower leaves, wilt, blight, and often death. The roots had a dark brown rot, and crowns were also rotted. The average incidence of the disease was up to 25%, and it even led to destruction and closure of a certain strawberry greenhouse. Root tissues (5 mm2) from 25 infected plants were excised from the central rotted root, surfaced sterilized by soaking in 75% ethyl alcohol for 30 s, rinsed three times in sterilized distilled water, and plated onto potato dextrose agar (PDA). All 25 isolates from each infected plant had the same morphological characteristics. They were able to grow at temperatures between 15 and 40°C, and there were no distinctive colony growth patterns on PDA. The sporangia were obovate or subglobose, papillate, and 21 to 34 × 20 to 28 µm in diameter. Oogonia were smooth and 22 to 30 µm in diameter. To confirm the identity of the pathogen, the rDNA internal transcribed spacer region (ITS, NCBI accession no. MT179561), cytochrome c oxidase I gene (cox I, MT188654), and cytochrome c oxidase II gene (cox II, MT188655) of three isolates were amplified and sequenced using the primer pairs ITS1/ITS4 (White et al. 1990), FM35/FM59, and FM66/FM58 (Martin 2000), respectively. BLAST analysis showed in all cases 98 to 100% identity with segments of Phytopythium helicoides (GenBank accession nos. MG597190.1 for ITS, KT258906.1 for cox I, and KT258907.1 for cox II). Based on the morphological features and the phylogenetic analyses of DNA sequences, the isolates were identified as P. helicoides. Pathogenicity assays were conducted on 3-week-old HongYan strawberry seedlings in September 2018. The roots of each seedling were dipped for 10 min into zoospore suspension of each isolate (1 × 106 zoospores/ml), and the control seedlings were inoculated using the same procedure with sterilized distilled water. Five replicate seedlings were inoculated and planted individually into 1.8-liter free-draining pots containing sterilized soil. All the seedlings were incubated at 22°C under a 16-h light/dark regime and watered with 50 ml every 5 days. All inoculated plants showed root necrosis and crown rot 20 days after inoculation. The symptoms of inoculated seedlings were similar to the naturally infected plants. The same pathogen was reisolated from symptomatic roots and crowns. No symptoms were observed in the control seedlings. Although P. helicoides has been reported causing root and crown rot on strawberry in Japan and America (Ishiguro et al. 2014; Marin et al. 2019), rhizome rot on Asian lotus, and stem rot on Shatangju mandarin in China (Chen et al. 2016; Yin et al. 2016), it has not been reported in China from strawberry. Thus, strawberry growers should consider this pathogen when diagnosing and managing plant diseases in this crop.The author(s) declare no conflict of interest.References:Chen, X., et al. 2016. Eur. J. Plant Pathol. 146:715. https://doi.org/10.1007/s10658-016-0952-4 Crossref, ISI, Google ScholarIshiguro, Y., et al. 2014. J. Gen. Plant Pathol. 80:423. https://doi.org/10.1007/s10327-014-0520-8 Crossref, ISI, Google ScholarMarin, M., et al. 2019. Plant Dis. 103:2696. https://doi.org/10.1094/PDIS-03-19-0658-PDN Link, Google ScholarMartin, F. 2000. Mycologia 92:711. https://doi.org/10.1080/00275514.2000.12061211 Crossref, ISI, Google ScholarWhite, T. J., et al. 1990. Page 315 in: PCR Protocols: A Guide to Methods and Applications. Academic Press, San Diego, CA. Crossref, Google ScholarYin, X., et al. 2016. Plant Dis. 100:532. https://doi.org/10.1094/PDIS-07-15-0833-PDN Link, ISI, Google ScholarThe author(s) declare no conflict of interest.Funding: Funding was provided by the Jiangsu Province Policy Guidance Program (no. BZ2018025).DetailsFiguresLiterature CitedRelated Vol. 104, No. 9 September 2020SubscribeISSN:0191-2917e-ISSN:1943-7692 DownloadCaptionRipening strawberry infected by Colletotrichum acutatum (M. Dowling et al.). Photo credit: M. Dowling. Diaporthe leaf spot caused by Diaporthe humulicola on hop cone tissue (E. Allan-Perkins et al.). Photo credit: M. Salvas. Metrics Downloaded 405 times Article History Issue Date: 26 Aug 2020Published: 8 Jul 2020First Look: 7 Apr 2020Accepted: 6 Apr 2020 Page: 2528 Information© 2020 The American Phytopathological SocietyFundingJiangsu Province Policy Guidance ProgramGrant/Award Number: BZ2018025KeywordsPhytopythium helicoidesstrawberryroot and crown rotThe author(s) declare no conflict of interest.Cited ByFirst Report of Phytopythium helicoides Causing Stalk Rot on Corn in ChinaX. Y. Xie, H. Z. Zhou, S. S. Fan, and X. J. Zhang15 November 2021 | Plant Disease, Vol. 0, No. 0Morphological and molecular characteristics of fungal species associated with crown rot of strawberry in South Korea3 November 2021 | Molecular Biology Reports, Vol. 10