First Report of the Apple Root-Knot Nematode, Meloidogyne mali, Infecting Crape Myrtle From Japan

Abstract

HomePlant DiseaseVol. 99, No. 6First Report of the Apple Root-Knot Nematode, Meloidogyne mali, Infecting Crape Myrtle From Japan PreviousNext DISEASE NOTES OPENOpen Access licenseFirst Report of the Apple Root-Knot Nematode, Meloidogyne mali, Infecting Crape Myrtle From JapanJ. F. Gu and J. HeJ. F. GuSearch for more papers by this author and J. HeSearch for more papers by this authorAffiliationsAuthors and Affiliations J. F. Gu J. He , Technical Centre, Ningbo Entry-exit Inspection and Quarantine Bureau, Ningbo 315012, Zhejiang, China. Published Online:27 May 2015https://doi.org/10.1094/PDIS-11-14-1145-PDNAboutSections ToolsAdd to favoritesDownload CitationsTrack Citations ShareShare onFacebookTwitterLinked InRedditEmailWechat Crape myrtle (Lagerstroemia indica L.) is commonly imported from Japan to Ningbo Port, China. In 2014, during inspections of imported crape myrtle plants for plant-parasitic nematodes, five of 51 inspected trees had roots showing small and round galls (0.4 to 0.7 mm in size). Females of Meloidogyne spp. were dissected from these galls. Nematodes were also extracted from soil surrounding the roots using a modified Baermann funnel methods and second-stage juveniles (J2) were detected. The perineal patterns of females (n = 10) were oval with smooth, fine striae. Both the dorsal and ventral arch were low and flat, and the phasmids were large and wider apart than the length of vulval slit. The body length and tail of J2 (n = 20) were short, 362 to 466 μm and 29.2 to 39.3 μm, respectively. Tail length/tail diameter (c′) = 11.6 to 15.3. These morphological characteristics were the same as those for Meloidogyne mali Itoh, Ohshima & Ichinohe, 1969 (2). The morphological identification was confirmed by sequence analysis of the D2-D3 expansion segment of the 28S rDNA gene following amplification with the primers D2A (5′-ACAAGTACCGTGAGGGAAAGTT-3′) and D3B (5′-TCGGAAGGAACCAGCTACTA-3′) (3). A PCR product approximately 780 bp in length was obtained and sequenced. The sequences were compared with previously published sequences in the NCBI database and showed 96 to 100% sequence similarity with M. mali (JX978226, KF880399, KF880398, and KF895396). Amplification and sequencing of the partial 18S rDNA gene was also performed with two overlapping PCR fragments. For the first fragment, primer 988F (5′-CTCAAAGATTAAGCCATGC-3′) was used in combination with the primer 1912R (5′-TTTACGGTCAGAACTAGGG-3′). The second fragment was amplified with primers 1813F (5′-CTGCGTGAGAGGTGAAAT-3′) and 2646R (5′-GCTACCTTGTTACGACTTTT-3′) (3). A PCR product approximately 1,750 bp in length was obtained and sequenced. Sequences were compared with those in the NCBI database and had 99 to 100% identity with sequences from M. mali (JX978225, EU669947 to EU669949). To our knowledge, this is the first report of the root-knot nematode M. mali in crape myrtle from Japan. M. mali was first reported in Japan in 1969, with the type host being apple. There are about 44 different plant species currently recognized as hosts for M. mali (1). It is highly probable that this root-knot nematode has an even wider host range and distribution than is currently known.