First Report of Southern Root-Knot Nematode, Meloidogyne incognita, on Large Crabgrass, Digitaria sanguinalis, in China

HomePlant DiseaseVol. 103, No. 10First Report of Southern Root-Knot Nematode, Meloidogyne incognita, on Large Crabgrass, Digitaria sanguinalis, in China PreviousNext DISEASE NOTES OPENOpen Access licenseFirst Report of Southern Root-Knot Nematode, Meloidogyne incognita, on Large Crabgrass, Digitaria sanguinalis, in ChinaW. W. Song, X. Shi, N. W. Qi, C. Liang, F. M. Duan, and H. H. ZhaoW. W. Songhttp://orcid.org/0000-0002-9156-4412Key Lab of Integrated Crop Pest Management of Shandong Province, College of Plant Health and Medicine, Qingdao Agricultural University, Qingdao 266109, ChinaSearch for more papers by this author, X. ShiKey Lab of Integrated Crop Pest Management of Shandong Province, College of Plant Health and Medicine, Qingdao Agricultural University, Qingdao 266109, ChinaSearch for more papers by this author, N. W. QiKey Lab of Integrated Crop Pest Management of Shandong Province, College of Plant Health and Medicine, Qingdao Agricultural University, Qingdao 266109, ChinaSearch for more papers by this author, C. Lianghttp://orcid.org/0000-0002-0139-8140Key Lab of Integrated Crop Pest Management of Shandong Province, College of Plant Health and Medicine, Qingdao Agricultural University, Qingdao 266109, ChinaSearch for more papers by this author, F. M. DuanKey Lab of Integrated Crop Pest Management of Shandong Province, College of Plant Health and Medicine, Qingdao Agricultural University, Qingdao 266109, ChinaSearch for more papers by this author, and H. H. Zhao†Corresponding author: H. H. Zhao; E-mail Address: hhzhao@qau.edu.cnKey Lab of Integrated Crop Pest Management of Shandong Province, College of Plant Health and Medicine, Qingdao Agricultural University, Qingdao 266109, ChinaSearch for more papers by this authorAffiliationsAuthors and Affiliations W. W. Song X. Shi N. W. Qi C. Liang F. M. Duan H. H. Zhao † Key Lab of Integrated Crop Pest Management of Shandong Province, College of Plant Health and Medicine, Qingdao Agricultural University, Qingdao 266109, China Published Online:24 Jul 2019https://doi.org/10.1094/PDIS-03-19-0641-PDNAboutSectionsSupplemental ToolsAdd to favoritesDownload CitationsTrack Citations ShareShare onFacebookTwitterLinked InRedditEmailWechat Large crabgrass, Digitaria sanguinalis (L.) Scop., is a weed seriously damaging agricultural production throughout tropical and temperate regions of the world (King and Oliver 1994). However, in China, D. sanguinalis is used as a traditional Chinese medicine that may have beneficial health effects on both lung and eyesight (Hu et al. 1999). In July 2017, numerous plants of D. sanguinalis with small to large galls on the root systems, typical of Meloidogyne infection, were observed in Qingdao, Shandong Province, China. The affected plants did not exhibit obvious above-ground symptoms. Infected roots were collected from a greenhouse, and nematodes were extracted from root samples. The morphological identification of the nematode was performed based on the characteristics of females, males, second-stage juveniles (J2s), and eggs (Eisenback et al. 1981). The measurement data are shown in the supplementary materials. The perineal patterns of females had a high dorsal arch, which was square or trapezoid, with smooth or wavy striae and lacking obvious lateral lines. The stylet knob of males extended horizontally and had a distinct boundary with the stylet shaft. All data and descriptions conformed to the morphological characteristics of Meloidogyne incognita (Kofoid & White, 1919) Chitwood, 1949. DNA was extracted from mature females. Species molecular identification was confirmed by sequence characterized amplified region (SCAR) markers specific for M. incognita. Two pairs of the species-specific SCAR primers, Finc/Rinc and IncK-14F/IncK-14R, were used to diagnose whether these nematodes from large crabgrass were M. incognita (Zijlstra et al. 2000; Randig et al. 2002). The fragments of 1,200 and 400 bp were observed under a UV light, respectively, confirming this population to be M. incognita. In addition, primers specific for M. arenaria (Far/Rar) and M. javanica (Fjav/Rjav) were also used but failed to amplify any fragments from the nematode DNA (Zijlstra et al. 2000; Randig et al. 2002). Ten D. sanguinalis plants about 15 cm long were transplanted into 20-cm-diameter pots in a growth chamber, and each seedling was inoculated with 4,000 J2s accompanied by uninoculated plants as the control. After 16 weeks, all inoculated plant roots showed galling symptoms, which were similar to those produced in the greenhouse. There were different life stages of the nematode in dissected galled tissues, with population densities ranging from 728 to 3,563 eggs and J2s per 5 g of fresh roots. The control seedlings had no galls. On the basis of these results, the population of Meloidogyne sp. on D. sanguinalis was confirmed to be M. incognita. M. incognita is one of the most devastating nematodes of economic crops and vegetables worldwide. D. sanguinalis has also been reported as a major host of M. incognita in Florida (Noling and Gilreath 2002), but in another study, D. sanguinalis was a nonhost of M. incognita in Florida (Kaur et al. 2007). The contradiction between the above two studies might be because of the different M. incognita races used. The discovery that D. sanguinalis could be infected by M. incognita is significant for integrated nematode management, particularly for crop rotation. To our knowledge, this is the first report of D. sanguinalis as a host of M. incognita in China.The author(s) declare no conflict of interest.References:Zijlstra, C., et al. 2000. Nematology 2:847. https://doi.org/10.1163/156854100750112798 Crossref, ISI, Google ScholarEisenback, J. D., et al. 1981. A Guide to the Four Most Common Species of Root-Knot Nematodes (Meloidogyne spp.), with a Pictorial Key. North Carolina State University, Raleigh, NC. Google ScholarHu, X. M., et al. 1999. Chinese Materia Medica. Shanghai Scientific and Technical Publishers, Shanghai, China. Google ScholarKaur, R., et al. 2007. Nematropica 37:107. Google ScholarKing, C. A., and Oliver, L. R. 1994. Weed Sci. 42:561. https://doi.org/10.1017/S0043174500076955 Crossref, ISI, Google ScholarNoling, J. W., and Gilreath, J. P. 2002. Page 49-1 in: Proceedings of the Annual International Research Conference on Methyl Bromide Alternative Reductions and Emissions Reductions. MBAO. Google ScholarRandig, O., et al. 2002. Genome 45:862. https://doi.org/10.1139/g02-054 Crossref, ISI, Google ScholarThe author(s) declare no conflict of interest.Funding: Funding was provided by Special Fund for Agro-scientific Research in the Public Interest (grant no. 201503114).DetailsFiguresLiterature CitedRelated Vol. 103, No. 10 October 2019SubscribeISSN:0191-2917e-ISSN:1943-7692 DownloadCaptionBell pepper cv. Bomby infected with zucchini yellow mosaic virus along with cucumber mosaic virus, pepper mild mottle virus, and tobacco mosaic virus (Verma et al.). Photo credit: S. Tripathi. Severe stunting, leaf chlorosis, and horizontal head growth of sunflower infected with Plasmopara halstedii, causal agent of downy mildew (Humann et al.). Photo credit: S. Markell. Metrics Article History Issue Date: 3 Oct 2019Published: 24 Jul 2019First Look: 23 May 2019Accepted: 17 May 2019 Page: 2694 Information© 2019 The American Phytopathological SocietyFundingSpecial Fund for Agro-scientific Research in the Public InterestGrant/Award Number: 201503114KeywordsMeloidogyne incognitaDigitaria sanguinalismorphological identificationmolecular identificationThe author(s) declare no conflict of interest.Cited byMeloidogyne incognita (root-knot nematode)CABI Compendium, Vol. CABI Compendium