Wang X Z, Wang L F, Piao C G, Guo M W, Li Y
The Key Laboratory of Forest Protection, State Forestry Administration, Research Institute of Forest Ecology, Environment and Protection, Chinese Academy of Forestry, Beijing 100091, China.
Plant Dis. 2012 Oct;96(10):1583. doi: 10.1094/PDIS-02-12-0144-PDN.
Atractylodis macrocephalae is an important Chinese herbal medicine plant and its rhizome is of high medicinal value. In recent years, a severe decline in yield has been observed in Bozhou City (China's largest A. macrocephalae producing area), Anhui Province, China. A survey for plant-parasitic nematodes was conducted in this area from June to September 2011. Stunted plants displayed chlorotic or necrotic lower leaves near the ground part by the growth reduction; examination of the roots of stunted plants revealed the presence of galls typical of infestation by root knot nematode. Root nodules were found on the tap and lateral roots caused the fleshy tap root deformity. The incidence of diseased plants was estimated to be 45%, and yield loss was quantified as 43.5%. Nematodes were extracted from the root samples as previously described (4) and identified by morphology, enzyme analysis, and molecular characterization. Morphology of the female perineal patterns and measurements of the second-stage juveniles (J2s) matched those of the original description of Meloidogyne arenaria. Enzyme analysis of the esterase (Est) phenotype was also typical of the AII phenotype in M. arenaria (2). DNA was extracted according to a modified protocol (1), and the rDNA-internal transcribed spacer (ITS1_5.8S_ITS2) region was amplified with universal primers V5367 (5'-TTGATTACGTCCCTGCCCTTT-3') and 26S (5'-TTTCACTCGCCGTTACTAAGG-3'). PCR yielded a fragment of 764 bp and the purified product was sequenced by Sanger's dideoxy chain termination method (ABI3730). Sequences were identical to that of M. arenaria in GenBank (Accession No. AF387092) (3). Amplification of the D2/D3 fragments of the 28S RNA with universal primers D2A (5'-ACAAGTACCGTGAGGGAAAGTTG-3') and D3B (5'-TCGGAAGGAACCAGCTACTA-3') yielded a PCR fragment of 758 bp. These sequences were also identical to that of M. arenaria in GenBank (Accession No. AF435803). For further confirmation, amplification of the IGS region with universal primers 5S (5'-TTAACTTGCCAGATCGGACG-3') and 18S (5'-TCTAATGAGGGAACCAGCTACTA-3') yielded a PCR fragment of 713 bp. These sequences were 99.64% homologous to that of M. arenaria (GenBank Accession No. MAU42342). To our knowledge, this is the first report of M. arenaria species on A. macrocephalae in China. The fleshy tap root of A. macrocephalae is the main edible part of the plant, and the damage caused by root knot nematode will potentially reduce the yield and quality of this herb. References: (1) J. L. Cenis et al. Phytopathology 83:76, 1993. (2) P. R. Esbenshade and A. C. Triantaphyllou. J. Nematol. 17:6, 1985. (3) T. C. Vrain et al. Appl Nematol. 15:563, 1992. (4) L. F. Wang et al. Forest Res. 14:484, 2001.
白术是一种重要的中药材植物，其根茎具有很高的药用价值。近年来，在中国安徽省亳州市（中国最大的白术产区）观察到产量严重下降。2011年6月至9月在该地区进行了植物寄生线虫调查。生长发育迟缓的植株表现为靠近地面部分的下部叶片黄化或坏死，生长受阻；对生长发育迟缓植株的根系检查发现存在根结线虫侵染典型的瘤状物。在主根和侧根上发现根瘤，导致肉质主根畸形。估计病株发生率为45%，产量损失量化为43.5%。按照先前描述的方法（4）从根样本中提取线虫，并通过形态学、酶分析和分子特征进行鉴定。雌虫会阴花纹的形态和二期幼虫（J2s）的测量结果与南方根结线虫的原始描述相符。酯酶（Est）表型的酶分析也为南方根结线虫的AII表型（2）。根据改良方案（1）提取DNA，用通用引物V5367（5'-TTGATTACGTCCCTGCCCTTT-3'）和26S（5'-TTTCACTCGCCGTTACTAAGG-3'）扩增核糖体DNA内部转录间隔区（ITS1_5.8S_ITS2）区域。PCR产生一个764 bp的片段，纯化产物通过桑格双脱氧链终止法（ABI3730）进行测序。序列与GenBank中南方根结线虫的序列相同（登录号AF387092）（3）。用通用引物D2A（5'-ACAAGTACCGTGAGGGAAAGTTG-3'）和D3B（5'-TCGGAAGGAACCAGCTACTA-3'）扩增28S RNA的D2/D3片段，得到一个758 bp的PCR片段。这些序列也与GenBank中南方根结线虫的序列相同（登录号AF435803）。为进一步确认，用通用引物5S（5'-TTAACTTGCCAGATCGGACG-3'）和18S（5'-TCTAATGAGGGAACCAGCTACTA-3'）扩增IGS区域，得到一个713 bp的PCR片段。这些序列与南方根结线虫（GenBank登录号MAU42342）的序列同源性为99.64%。据我们所知，这是中国首次报道南方根结线虫侵染白术。白术的肉质主根是该植物的主要可食用部分，根结线虫造成的损害可能会降低这种药材的产量和质量。参考文献：（1）J. L. Cenis等人，《植物病理学》83:76，1993年。（）P. R. Esbenshade和A. C. Triantaphyllou，《线虫学杂志》17:6，1985年。（3）T. C. Vrain等人，《应用线虫学》15:563，1992年。（4）L. F. Wang等人，《林业研究》14:484，2001年。
