Lu X H, Solangi Ghulam Sarwar, Huang J L, Liu Z M, Qin Li-Ping
Nanning, Guangxi, China;
Sindh Agriculture University, 66973, Entomology, Umerkot, Tandojam, Pakistan, 530007.
Plant Dis. 2023 Apr 5. doi: 10.1094/PDIS-02-23-0282-PDN.
Antirrhinum majus L. is a medicinal and ornamental herb commonly grown in China. In October 2022, A. majus plants were observed stunted in growth with yellowish leaves and containing a large number of galls on roots in a field in Nanning, Guangxi, China (N22°47'23.35″, E108°23'4.26). Ten samples were collected randomly from rhizosphere soil and roots of A. majus. Second-stage juveniles (J2) were isolated from fresh soil with a Baermann funnel, and a mean of 36 ± 2.9 per 500 cm3 of soil was recorded. Gall roots were dissected using a microscope, where 2+ 0.42 males per sample were recovered. The species was determined to be Meloidogyne enterolobii based on morphological characteristics, including the female perineal pattern, and DNA studies. Female perineal patterns and morphometric data were similar to the original description of M. enterolobii Yang and Eisenback 1983 from Enterolobium contortisilquum (Vell.) Morong in China (Yang and Eisenback 1983). The measurements of males (n = 10) included body length, 1600.7 ± 55.32 (1421.3 to 1924.3) µm; body diameter = 41.3 ± 0.80 (37.8 to 45.4) µm, stylt length = 20.5 ± 0.40 (19.1 to 22.2) µm, spicules length = 30.0 ± 0.47 (28.2 to 32.0) µm and DGO = 4.5 ± 0.3 (3.8 to 5.2) µm. Measurements of J2 (n = 20) included body length, 441.9 ± 5.42 (403.2 to 493.3) µm; body diameter = 16.6 ± 0.30 (14.4 to 8.7) µm, a = 26.8 ± 0.54 (21.9 to 31.2), c = 8.7 ± 0.27 (6.4 to 10.8), stylet length = 12.6 ± 0.17 (11.2 to 14.3) µm, DGO = 3.8 ± 0.10 (2.9 to 4.8) µm, tail length = 51.6 ± 1.27 (42.3 to 63.1) µm and hyaline tail terminus length = 11.7 ± 0.15 (10.2 to 13.1) µm. These morphological characteristics are similar to the original description of M. enterolobii (Yang and Eisenback 1983). Pathogenicity tests were conducted on A. majus 'Taxiti' plants directly germinated from seeds in a 10.5-cm-diameter pot filled with 600 ml of sterilized peat moss/sand (1:1, v/v) soil in the glasshouse. After 1 week, fifteen plants were inoculated with 500 J2/pot (nematode culture collected from the original field) and five uninoculated plants served as a control. After 45 days, aboveground parts of all inoculated plants showed symptoms similar to those observed in the field. No symptoms were observed on control plants. The RF value of the inoculated plants was determined by the method of Belair and Benoit (1996) 60 days after inoculation, and the average was 14.65. J2 were used in this test and sequenced on 28S rRNA-D2/D3, ITS, COII -16SrRNA 3 region and confirmed to be M. enterolobii. Species identification was confirmed by using polymerase chain reaction primers D2A/D3B (De Ley et al. 1999), F194/5368r (Ferris et al. 1993), C2F3/1108 (Powers and Harris, 1993). The sequences obtained GenBank accession numbers OP897743 (COII), OP876758 (rRNA) and OP876759 (ITS) were 100% similar to other M. enterolobii populations from China (MN269947), (MN648519) and (MT406251). M. enterolobii is a highly pathogenic species and has been reported in vegetables, ornamental plants, guava (Psidium guajava L.), and weeds in China, Africa and America (Brito et al. 2004; Xu et al. 2004; Yang and Eisenback 1983). The medicinal plant Gardenia jasminoides J. Ellis was also infected by M. enterolobii in China (Lu et al. 2019). Of concern is its ability to develop on crop genotypes carrying RKN resistance genes in tobacco (Nicotiana tabacum L.), tomato (Solanum lycopersicum L.), soybean (Glycine max (L.) Merr.), potato (Solanum tuberosum L.), cowpea (Vigna unguiculata (L.) Walp.), sweetpotato (Ipomoea batatas (L.) Lam.), and cotton (Gossypium hirsutum L.). Consequently, this species was added to the European and Mediterranean Plant Protection Organization A2 Alert List in 2010. This is the first natural infection report of M. enterolobii in Guangxi, China on the medicinal and ornamental herb A. majus. Acknowledgments This research was funded by the National Natural Science Foundation of China (31860492), Natural Science Foundation of Guangxi (2020GXNSFAA297076), and Guangxi Academy of Agricultural Sciences Fund, China (2021YT062, 2021JM14, 2021ZX24). References: Azevedo de Oliveira, S., et al. 2018. PLoS One 13:e0192397. Belair, G., and Benoit, D. L. 1996. J. Nematol. 28:643. Brito, J. A., et al. 2004. J. Nematol. 36:324. De Ley, P., et al. 1999. Nematol. 1:591-612. Ferris, V. R., et al. 1993. Fundam. Appl. Nematol. 16:177-184. Lu, X. H., et al. 2019. Plant Dis. 103:1434. Powers, T. O. and Harris, T. S. 1993. J. Nematol. 25:1-6 Vrain, T. C., et al. 1992. Fundam. Appl. Nematol. 15:563. Yang, B. and Eisenback, J. D. 1983. J. Nematol. 15:381.
金鱼草是一种常见于中国的药用和观赏草本植物。2022年10月，在中国广西南宁的一块田地中（北纬22°47'23.35″，东经108°23'4.26），观察到金鱼草植株生长发育不良，叶片发黄，根部有大量虫瘿。从金鱼草的根际土壤和根部随机采集了10个样本。用贝尔曼漏斗从新鲜土壤中分离出二龄幼虫（J2），每500立方厘米土壤中平均记录到36±2.9条。使用显微镜解剖有虫瘿的根，每个样本回收了2±0.42条雄虫。根据包括雌虫会阴花纹在内的形态特征以及DNA研究，确定该物种为南方根结线虫。雌虫会阴花纹和形态测量数据与1983年杨和艾森巴克对中国南方根结线虫（从扭荚相思中分离得到）的原始描述相似（杨和艾森巴克，1983年）。雄虫（n = 10）的测量数据包括体长，1600.7±55.32（1421.3至1924.3）微米；体宽 = 41.3±0.80（37.8至45.4）微米，口针长 = 20.5±0.40（19.1至22.2）微米，交合刺长 = 30.0±0.47（28.2至32.0）微米，背食道腺开口到口针基部的距离（DGO） = 4.5±0.3（3.8至5.2）微米。J2（n = 20）的测量数据包括体长，441.9±5.42（403.2至493.3）微米；体宽 = 16.6±0.30（14.4至8.7）微米，a值 = 26.8±0.54（21.9至31.2），c值 = 8.7±0.27（6.4至10.8），口针长 = 12.6±0.17（11.2至14.）微米，DGO = 3.8±0.10（2.9至4.8）微米，尾长 = 51.6±1.27（42.3至63.1）微米，透明尾端长 = 11.7±0.15（10.2至13.1）微米。这些形态特征与南方根结线虫的原始描述相似（杨和艾森巴克，1983年）。在温室中，对直接从种子萌发的金鱼草‘塔西提’植株进行致病性测试，花盆直径为10.5厘米，装有600毫升经过消毒的泥炭藓/沙子（1:1，体积/体积）土壤。1周后，每盆接种500条J2（从原始田地采集的线虫培养物），共接种15株，5株未接种的植株作为对照。45天后所有接种植株的地上部分出现了与田间观察到的症状相似的症状。对照植株未观察到症状。接种60天后，按照贝莱尔和贝努瓦（1996年）的方法测定接种植株的RF值，平均值为14.65。本试验使用J2，并对其28S rRNA - D2/D（3）、ITS、COII - 16SrRNA 3个区域进行测序，确认其为南方根结线虫。使用聚合酶链反应引物D2A/D3B（德莱伊等人，1999年）、F194/5368r（费里斯等人，1993年）、C2F3/1108（鲍尔斯和哈里斯，1993年）进行物种鉴定确认。获得的序列GenBank登录号OP897743（COII）、OP876758（rRNA）和OP876759（ITS）与来自中国的其他南方根结线虫种群（MN269947）、（MN648519）和（MT406251）100%相似。南方根结线虫是一种高致病性病原体，在中国、非洲和美洲的蔬菜、观赏植物、番石榴（Psidium guajava L.）和杂草中均有报道（布里托等人，2004年；徐等人，2004年；杨和艾森巴克，1983年）。中国的药用植物栀子（Gardenia jasminoides J. Ellis）也受到南方根结线虫的感染（陆等人，2019年）。令人担忧其在携带根结线虫抗性基因的烟草（Nicotiana tabacum L.）、番茄（Solanum lycopersicum L.）、大豆（Glycine max (L.) Merr.）、马铃薯（Solanum tuberosum L.）、豇豆（Vigna unguiculata (L.) Walp.）、甘薯（Ipomoea batatas (L.) Lam.）和棉花（Gossypium hirsutum L.）等作物基因型上发育的能力。因此，该物种在2010年被列入欧洲和地中海植物保护组织A2预警名单。这是中国广西首次关于南方根结线虫对药用和观赏草本植物金鱼草自然感染的报道。致谢本研究由中国国家自然科学基金（31860492）、广西自然科学基金（2020GXNSFAA297076）和中国广西农业科学院基金（2021YT062、2021JM14、2021ZX24）资助。参考文献：阿泽维多·德·奥利维拉，S.等人，2018年。《公共科学图书馆·综合》13:e0192397。贝莱尔，G.和贝努瓦，D. L.，1996年。《线虫学杂志》28:643。布里托，J. A.等人，2004年。《线虫学杂志》36:（324）。德莱伊，P.等人，1999年。《线虫学》1:591 - 612。费里斯，V. R.等人，1993年。《基础与应用线虫学》16:177 - 184。陆，X. H.等人，2019年。《植物病害》1（03）:1434。鲍尔斯，T. O.和哈里斯（T. S.），1993年。《线虫学杂志》25:1 - 6。弗雷恩，T. C.等人，1992年。《基础与应用线虫学》15:563。杨，B.和艾森巴克，J. D.，1983年。《线虫学杂志》15:381。
