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First Report of Soybean Cyst Nematode (Heterodera glycines Ichinohe) on Soybean in the Province of Quebec, Canada

In eastern Canada, soybean, Glycine max (L.) Merr., is the most important legume, and its cultivation is expanding to new regions as cultivars for the short growing season are developed. The soybean cyst nematode (SCN), Heterodera glycines Ichinohe, is among the most destructive pests of soybean in the world. This nematode is also under quarantine regulations in many countries, including Canada. Until now, in Canada, SCN was only reported in the province of Ontario. Since its first detection in 1988 in the southwestern part of the province (1), SCN has been found in 12 other counties. It appears that SCN has been spreading in a north and northeast direction along the St. Lawrence River. We report here the first detection of SCN in the province of Quebec. Second stage juveniles (J2) and cysts were found in St. Anicet, Quebec, Canada, in a 10-ha soybean field. Light textured soil is a characteristic of the field, the same site where Pratylenchus alleni was recently discovered (2) and where irregular patches of stunted soybean plants were observed. Morphological and molecular studies of J2 and cysts confirmed the identification of this nematode population as SCN. The J2 were typical for SCN with a body length of 393 to 428 μm, lateral fields harboring four straight lines, a well-developed stylet 23 to 25 μm long, sub-ventral base knobs with posterior slops, a tail length of 43 to 50 μm, and a hyaline part of 23 to 29 μm. Cysts were brown and lemon-shaped with a posterior protuberance, ambifenestrated, underbridged, and had a strongly developed bullae. Key morphometrics were: a cyst fenestra 40 to 57 μm long and 28 to 44 μm wide, and a vulval slit 39 to 53 μm long. All of these are coincident with those of SCN (3). Ribosomal DNA of the ITS, 18S, and D2/D3 regions, and mitochondrial COX1 gene were PCR amplified from cysts and J2s gDNA using primers ITS-F (5′-TTGATTACGTCCCTGCCCTTT-3′) and ITS-R (5′-ACGAGCCGAGTGATCCACCG-3′); 18S-F (5′-TTGGATAACTGTGGTTTAACTAG-3′) and 18S-R (5′-ATTTCACCTCTCACGCAACA-3′); D2A (5′-ACAAGTACCGTGAGGGAAAGT-3′) and D3B (5′-GACCCGTCTTGAAACACGGA-3′); and COXI-F (5′-CCTACTATGATTGGTGGTTTTGGTAATTG-3′) and COX1-R (5′-GTAGCAGCAGTAAAATAAGCACG-3′), respectively, and sequenced. The nucleotide sequences were 98 to 100% similar to those of SCN found in NCBI nr database (July 2013). All the sequences have been submitted to GenBank with the following accession numbers: ITS (KF453621); 18S (KF453622); D2/D3 (KF453623); and COX1 (KF453624). Using species specific sequence characterized amplified region (SCAR) primers (4) also confirmed this was H. glycines. This is the first reported case of SCN in Quebec, Canada. The proximity of St. Anicet to the Ontario border is in accordance with the North/Northeastern dispersal hypothesis. The HG type of the SCN population will have to be determined before any resistant cultivars are deployed for the management of this pathogen in the province.

References: (1) T. R. Anderson et al. Plant Dis. 72:453, 1988. (2) G. Bélair et al. Plant Dis. 97:292, 2013. (3) R. H. Mulvey. Can. J. Zool. 50:1277, 1972. (4) S. Ou et al. Nematology 10:397, 2008.