荞麦(FagopyrumesculentumMoench)属于虎杖科,由于其高营养而被广泛种植,营养食品,和药用特性。巴西排名第七,2018年产量为66,000吨。荞麦还因其作为覆盖作物的适应性而受到重视,在大豆的谷物田中(甘氨酸max(L.)合并。,玉米(玉米L.),和高粱(双色高粱(L.)Moench)(Görgen等人。2016年,巴布等人。2018),尤其是在高度感染植物寄生线虫(PPN)的领域。PPN造成严重的根部损伤,抑制植物发育和产量生产。2018年10月,在有症状的荞麦斑块中收集了六个根和土壤样本,在瓜伊拉SP(20°19\'32\“S48°13\'15.4\”W)。样本在线虫实验室(LabNema)进行了分析,UNESP,Jaboticabal,SP,BR.植物表现出黄叶的症状,根部发臭和体积减少。根结线虫。被发现,由10g根中的6,320个卵和第二阶段的幼体(J2s)和100cm的土壤中的1,628个J2s组成。成人形态特征,酯酶同工酶表型,并进行分子分析以鉴定根结线虫物种。会阴模式呈现高梯形背弓(n=15),雄性显示出梯形的唇区,包括一个由一个大的圆形唇盘形成的高头帽,该唇盘升高到内侧嘴唇上方并居中凹入(n=15)(Eisenback和Hirscmann1981)。这些特征在南方根结线虫(Kofoid和White,1912)奇特伍德,1949年(纳西门托等人。,2020年;Eisenback和Hirschmann1981;Netscher和Taylor1974)。用雌性(n=8)进行酶表型,表型I1得到验证,Esbenshade和Triantaphyllou(1985)描述为隐身分枝杆菌的典型特征。为确认物种DNA样本是从单个雌性(n=6)中提取的,并用特定引物进行PCR,以标记M.incognita(Mi-F5'-GTGAGATTCAGCTCCCCCCCAG-3'和Mi-R5'-ACGAGGGGAACATCTCCGTCC-3')和M.javanica(Treub)ChitGATGACTCAC(2004)和Zijlstra等人。(2000),分别,以及Long等人描述的扩增rDNA-IGS2区域的肠球菌和Eisenback1983年的特异性引物(Me-F5'-AACTTTGTGAAAGTGCCGCTG-3'和Me-R5'-TCAGTTCAGGCAGGATCAACC-3')。(2006)进行了测试。在Mi-F/R引物中扩增了955pbDNA大小的片段,这证实了M.incognita的身份(孟等人Al.,2004).使用原始人群进行致病性测试。在温室里,单个荞麦种子(简历。IPR91Baili)播种在六个装有高压灭菌土壤的5L盆中,并在每个盆中接种3,000个鸡蛋和J2s(n=6)和对照(n=6)。60天后,从根中提取线虫,并确认了M.incognita。平均回收了15738个鸡蛋和J2s,(生殖系数=5.24),这证实了荞麦是M.incognita的寄主。接种的植物表现出在田间观察到的症状。在对照上没有注意到症状或线虫。据报道,隐匿的Meloidogyne对加利福尼亚的F.esculentum造成了严重损害(Gardner和Caswell-Chen1994)以及巴西的几种作物(Nascimento等人。,2020)。然而,这是该线虫在巴西感染荞麦的第一份报告。鉴于荞麦在巴西的重要性,广泛用作牧草,覆盖作物,和它的营养特性,本报告对采取具体的管理措施是必不可少的,以避免进一步的损失。
Buckwheat (Fagopyrum esculentum Moench) belongs to the Polygonaceae family and has been widely cultivated due to its high nutritional, nutraceutical, and medicinal properties. Brazil ranks seventh-largest producer, with 66,000 tons produced in 2018. Buckwheat is also valued for its adaptability as a cover crop, in grain fields of soybean (Glycine max (L.) Merr., maize (Zea mays L.), and sorghum (Sorghum bicolor (L.) Moench) (Görgen et al. 2016, Babu et al. 2018) especially in fields highly infested with plant-parasitic nematodes (PPN). PPN cause severe root damage, suppressing plant development and yield production. In October 2018, six samples of roots and soil were collected in symptomatic patches of buckwheat, in Guaíra SP (20° 19\' 32\"S 48° 13\' 15.4\"W). Samples were analyzed in the Nematology Laboratory (LabNema), UNESP, Jaboticabal, SP, BR. Plants presented symptoms of yellow leaves and galled and volume-reduced roots. Meloidogyne sp. was found, comprising 6,320 eggs and second-stage juveniles (J2s) from 10 g of root and 1,628 J2s in 100 cm³ of soil. Adult morphological characteristics, isoenzyme phenotype of esterase, and molecular analysis were performed to identify the Meloidogyne species. The perineal patterns presented high and trapezoidal dorsal arch (n=15), and the males showed a trapezoidal labial region, including a high head cap formed by a large round labial disc that is raised above the medial lips and centrally concave (n=15) (Eisenback and Hirscmann 1981). These characteristics are typical in Meloidogyne incognita (Kofoid and White, 1912) Chitwood, 1949 (Nascimento et al., 2020; Eisenback and Hirschmann 1981; Netscher and Taylor 1974). The enzymatic phenotype was performed with females (n=8), and the phenotype I1 was verified, described by Esbenshade and Triantaphyllou (1985) as typical for M. incognita. To confirm the species DNA samples were extracted from individual females (n=6) and PCR with specific primers for M. incognita (Mi-F 5\'- GTGAGGATTCAGCTCCCCAG-3\' and Mi-R 5\'-ACGAGGAA CATACTTCTCCGTCC-3\') and M. javanica (Treub) Chitwood 1949 (Fjav 5\'-GGTGCGCGATTGAACTGAGC-3\' and Rjav 5\'-CAG GCCCTTCAGTGGAACTATAC-3\') that amplify SCAR markers described by Meng et al. (2004) and Zijlstra et al. (2000), respectively, and specific primers for M. enterolobii Yang & Eisenback 1983 that amplify rDNA-IGS2 region (Me-F 5\'-AACTTTTG TGAAAGTGCCGCTG-3\' and Me-R 5\'-TCAGTTCAGGCAGG ATCAACC-3\') described by Long et al. (2006) were tested. A fragment of 955 pb DNA size was amplified in Mi-F/R primer, which confirmed the M. incognita identification (Meng et. al., 2004). The original population was used to execute pathogenicity test. In a greenhouse, single buckwheat seeds (cv. IPR 91 Baili) were sown in six 5L pots filled with autoclaved-soil and inoculated with 3,000 eggs and J2s per pot (n=6) and control (n=6). After 60 days, the nematodes were extracted from roots and the M. incognita was confirmed. An average of 15,738 eggs and J2s were recovered, (reproductive factor = 5.24), which confirmed buckwheat as a host to M. incognita. The inoculated plants showed symptoms as those observed in the field. No symptom or nematode was noted on the control. Meloidogyne incognita has been reported causing high damage to the F. esculentum in California (Gardner and Caswell-Chen 1994) plus several crops in Brazil (Nascimento et al., 2020). However, this is the first report of this nematode infecting buckwheat in Brazil. Given the importance of buckwheat in Brazil, with extensive use as forage, cover crop, and its nutritional properties, this report is essential to specific management measures are adopted to avoid further losses.