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HomePlant DiseaseAhead of PrintFirst Report of Meloidogyne javanica Infecting Bletilla striata in Yunnan, China PreviousNext DISEASE NOTE OPENOpen Access licenseFirst Report of Meloidogyne javanica Infecting Bletilla striata in Yunnan, ChinaYanmei Yang, Pengjun Wang, Xinghua Yu, Yanqiong Dai, Hanyang Yao, Yunxia Li, Qiankun Li, and Xianqi HuYanmei Yanghttps://orcid.org/0000-0002-0858-2303College of Plant Protection, Yunnan Agricultural University, Kunming 650201, Yunnan, ChinaState Key Laboratory of Biological Resources Protection and Utilization, Kunming 650201, Yunnan, ChinaSearch for more papers by this author, Pengjun WangAgricultural Technology Extension Center of Xuanwei, Xuanwei 655400, ChinaSearch for more papers by this author, Xinghua YuStudent Affairs Departments, Yunnan Agricultural University, Kunming 650201, Yunnan, ChinaSearch for more papers by this author, Yanqiong DaiAgricultural Technology Extension Center of Xuanwei, Xuanwei 655400, ChinaSearch for more papers by this author, Hanyang YaoCollege of Plant Protection, Yunnan Agricultural University, Kunming 650201, Yunnan, ChinaState Key Laboratory of Biological Resources Protection and Utilization, Kunming 650201, Yunnan, ChinaSearch for more papers by this author, Yunxia LiCollege of Plant Protection, Yunnan Agricultural University, Kunming 650201, Yunnan, ChinaState Key Laboratory of Biological Resources Protection and Utilization, Kunming 650201, Yunnan, ChinaSearch for more papers by this author, Qiankun LiCollege of Plant Protection, Yunnan Agricultural University, Kunming 650201, Yunnan, ChinaState Key Laboratory of Biological Resources Protection and Utilization, Kunming 650201, Yunnan, ChinaSearch for more papers by this author, and Xianqi Hu†Corresponding author: X. Q. Hu; E-mail Address: [email protected]College of Plant Protection, Yunnan Agricultural University, Kunming 650201, Yunnan, ChinaState Key Laboratory of Biological Resources Protection and Utilization, Kunming 650201, Yunnan, ChinaSearch for more papers by this authorAffiliationsAuthors and Affiliations Yanmei Yang1 2 Pengjun Wang3 Xinghua Yu4 Yanqiong Dai3 Hanyang Yao1 2 Yunxia Li1 2 Qiankun Li1 2 Xianqi Hu1 2 † 1College of Plant Protection, Yunnan Agricultural University, Kunming 650201, Yunnan, China 2State Key Laboratory of Biological Resources Protection and Utilization, Kunming 650201, Yunnan, China 3Agricultural Technology Extension Center of Xuanwei, Xuanwei 655400, China 4Student Affairs Departments, Yunnan Agricultural University, Kunming 650201, Yunnan, China Published Online:20 Sep 2023https://doi.org/10.1094/PDIS-02-23-0215-PDNAboutSectionsView articlePDFSupplemental ToolsAdd to favoritesDownload CitationsTrack Citations ShareShare onFacebookTwitterLinked InRedditEmailWechat View articleBletilla striata (Thunb. ex Murray) Rchb. F. (family Orchidaceae) is an endangered traditional Chinese medicinal plant and has been traditionally used for hemostasis and detumescence in China (Wang et al. 2022). In March of 2021, during a field survey in Xuanwei City, Yunnan Province, China, some B. striata plants with symptoms of plant dwarfing and leaf yellowing were observed. Roots of diseased plants presented numerous galls, typical symptoms of root-knot nematode (RKN) infection. The diseased area was approximately 66,667 m2, showing a patchy disease distribution pattern. To identify the species of RKNs, females and eggs were isolated from galled tissues, and second-stage juveniles (J2s) hatched from eggs were collected. Nematodes were identified through comprehensive morphological and molecular methods. The perineal pattern of females was round to ovoid with a flat or moderately high dorsal arch and had two conspicuous lateral line striae. Morphological measurements of females (n = 20) included body length (L) = 702.9 ± 70.8 (556.2 to 780.2) μm, body width (BW) = 404.1 ± 48.5 (327.5 to 470.1) μm, stylet length = 15.5 ± 2.2 (12.3 to 18.6) μm, and distance from the base of the stylet to the dorsal esophageal gland opening (DGO) = 3.7 ± 0.8 (2.1 to 4.9) μm. The morphometrics of J2s (n = 20) were L = 438.4 ± 22.6 (354.1 to 464.8) μm, BW = 17.4 ± 2.0 (12.9 to 20.8) μm, stylet length = 13.5 ± 0.4 (13.0 to 14.2) μm, DGO = 3.2 ± 0.6 (2.6 to 4.7) μm, and hyaline tail terminus = 12.3 ± 1.9 (9.6 to 15.7) μm. These morphological characteristics were similar to the original descriptions of Meloidogyne javanica (Rammah and Hirschmann 1990). DNA extraction was done 60 times, each from a different single female, following the method of Yang et al. (2020). Amplification of the ITS1-5.8S-ITS2 region of rDNA and the coxI region of mtDNA was done by using the primers 18S/26S (5′-TTGATTACGTCCCTGCCCTTT-3′/5′-TTTCACTCGCCGTTACTAAGG-3′) (Vrain et al. 1992) and cox1F/cox1R (5′-TGGTCATCCTGAAGTTTATG-3′/5′-CTACAACATAATAAGTATCATG-3′) (Trinh et al. 2019), respectively. The PCR amplification program followed the method described by Yang et al. (2021). The ITS1-5.8S-ITS2 gene sequence (768 bp, GenBank accession no. OQ091922) showed 99.35 to 100% similarity to the known sequences of M. javanica (GenBank accession nos. KX646187, MW672262, KJ739710, KP901063, and MK390613). The coxI gene sequence (410 bp, OQ080070) showed 99.75 to 100% similarity to the known sequences of M. javanica (OP646645, MZ542457, KP202352, KU372169, and KU372170). Furthermore, the M. javanica species-specific primers Fjav/Rjav (5′-GGTGCGCGATTGAACTGAGC-3′/5′-CAGGCCCTTCAGTGGAACTATAC-3′) were used for PCR amplification. An expected fragment of approximately 670 bp was obtained, which was identical to that previously reported for M. javanica (Zijlstra et al. 2000). To verify pathogenicity of this nematode on B. striata, six 1.6-year-old tissue culture seedlings of B. striata were maintained in 10-cm-diameter × 9-cm-high plastic pots containing a sterilized mixed soil (humus soil/laterite soil/perlite = 3:1:1), and each plant was inoculated with 1000 J2s hatched from eggs of M. javanica. Three noninoculated B. striata were used as the negative controls. All plants were placed in a greenhouse at approximately 14 to 26°C. After 90 days, the inoculated plants presented symptoms such as leaf yellowing and root knots identical to those observed in the fields. The root gall rating was 2 according to the 0-to-5 RKNs rating scale (Anwar and McKenry 2002), and the reproductive factor (RF = final population/initial population) was 1.6. No symptoms or nematodes were observed on the control plants. The nematode was reisolated and identified as M. javanica by morphological and molecular methods as described above. To our knowledge, this is the first report of infection of M. javanica on B. striata. The infection of this economically important medicinal plant with M. javanica could pose a great threat to B. striata production in China, and further research will be necessary to develop control strategies.The author(s) declare no conflict of interest.References:Anwar, S. A., and McKenry, M. V. 2002. J. Nematol. 34:28. ISI, Google ScholarRammah, A., and Hirschmann, H. 1990. J. Nematol. 2:56. Google ScholarTrinh, Q. P., et al. 2019. J. Helminthol. 93:242. https://doi.org/10.1017/S0022149X18000202 Crossref, ISI, Google ScholarVrain, T. C., et al. 1992. Nematology 15:563. ISI, Google ScholarWang, H. Y., et al. 2022. Plant Dis. 106:1070. https://doi.org/10.1094/PDIS-07-21-1486-PDN Link, ISI, Google ScholarYang, Y. M., et al. 2020. J. Plant Prot. 47:657. https://doi.org/10.13802/j.cnki.zwbhxb.2020.2019154 Google ScholarYang, Y. M., et al. 2021. PLoS One 16:e0245201. https://doi.org/10.1371/journal.pone.0245201 Crossref, ISI, Google ScholarZijlstra, C., et al. 2000. Nematology 2:847. https://doi.org/10.1163/156854100750112798 Crossref, ISI, Google ScholarFunding: This research was supported by the Basic Research Special Project-Youth Project (202301AU070116) and Startup Funding for Doctoral Scientific Research (KY2022-40).The author(s) declare no conflict of interest.DetailsFiguresLiterature CitedRelated Just PublishedSubscribeISSN:0191-2917e-ISSN:1943-7692 Metrics Article History Published: 20 Sep 2023First Look: 29 Jun 2023Accepted: 27 Jun 2023 Information© 2023 The American Phytopathological SocietyFundingBasic Research Special Project-Youth ProjectGrant/Award Number: 202301AU070116Startup Funding for Doctoral Scientific ResearchGrant/Award Number: KY2022-40KeywordsBletilla striataMeloidogyne javanicanematodepathogen detectionThe author(s) declare no conflict of interest.PDF download