Joseph Soumi, Mekete Tesfamariam, Danquah Wiseborn B, Noling Joseph
University of Florida, Entomology and Nematology Department; Gainesville 32611.
Department of Plant Pathology, University of California, Davis 95616.
Plant Dis. 2016 Jul;100(7):1438-1445. doi: 10.1094/PDIS-09-15-1113-RE. Epub 2016 Apr 4.
Meloidogyne haplanaria is a species originally found infesting peanut in Texas and, more recently, in Arkansas. In this study, we confirmed the presence of M. haplanaria in Florida based on morphological and molecular characterization. This species was identified from a sample submitted for diagnosis collected from Mi-resistant tomato rootstock grown in Naples, FL. The major diagnostic criteria to distinguish M. haplanaria from other closely related root-knot nematode (RKN) species are based on morphological differences and host range tests, which are time consuming and labor intensive and require living or well-preserved specimens. In our study, we provide an easy diagnostic strategy to distinguish M. haplanaria from other RKN species based on amplification of two mitochondrial DNA regions. These regions span the intergenic spacer and part of the adjacent large subunit ribosomal RNA gene (lrDNA) and sequence polymorphisms in lrDNA revealed by the restriction pattern following digestion with the restriction enzymes HinfI and MnlI. A unique haplotype pattern, which has not been observed in any of the RKN species described thus far, was observed in M. haplanaria. The outcome of molecular analysis of M. haplanaria aligned with morphological measurement and characteristics as well as perineal pattern originally described for M. haplanaria.
南方根结线虫是一种最初在得克萨斯州被发现侵染花生的线虫物种，最近在阿肯色州也有发现。在本研究中，我们基于形态学和分子特征确认了佛罗里达州存在南方根结线虫。该物种是从佛罗里达州那不勒斯种植的抗根结线虫番茄砧木上采集的一份送检诊断样本中鉴定出来的。区分南方根结线虫与其他近缘根结线虫物种的主要诊断标准基于形态差异和寄主范围测试，这些方法既耗时又费力，且需要活的或保存良好的标本。在我们的研究中，我们提供了一种基于两个线粒体DNA区域扩增来区分南方根结线虫与其他根结线虫物种的简易诊断策略。这些区域跨越基因间隔区和相邻的大核糖体RNA基因（lrDNA）的一部分，通过用限制性内切酶HinfI和MnlI消化后的限制性图谱揭示lrDNA中的序列多态性。在南方根结线虫中观察到一种独特的单倍型模式，这在迄今为止描述的任何根结线虫物种中都未观察到。南方根结线虫的分子分析结果与最初描述的南方根结线虫的形态测量、特征以及会阴花纹一致。
