ARC Plant Protection Research Institute, P. Bag X5017, Stellenbosch, 7599.
Stud Mycol. 2006;55:65-74. doi: 10.3114/sim.55.1.65.
Die-back of rooibos (Aspalathus linearis) causes substantial losses in commercial Aspalathus plantations in South Africa. In the past, the disease has been attributed to Phomopsis phaseoli (teleomorph: Diaporthe phaseolorum). Isolates obtained from diseased plants, however, were highly variable with regard to morphology and pathogenicity. The aim of the present study was thus to identify the Phomopsis species associated with die-back of rooibos. Isolates were subjected to DNA sequence comparisons of the internal transcribed spacer region (ITS1, 5.8S, ITS2) and partial sequences of the translation elongation factor-1 alpha gene. Furthermore, isolates were also compared in glasshouse inoculation trials on 8-mo-old potted plants to evaluate their pathogenicity. Five species were identified, of which D. aspalathi (formerly identified as D. phaseolorum or D. phaseolorum var. meridionalis) proved to be the most virulent, followed by D. ambigua, Phomopsis theicola, one species of Libertella and Phomopsis, respectively, and a newly described species, P. cuppatea. A description is also provided for D. ambigua based on a newly designated epitype specimen.
南非商业化罗布斯塔茶（Aspalathus linearis）种植园的罗布斯塔茶枯萎病造成了巨大损失。过去，这种疾病被归因于 Phomopsis phaseoli（同物异名：Diaporthe phaseolorum）。然而，从患病植物中获得的分离物在形态和致病性方面差异很大。因此，本研究的目的是鉴定与罗布斯塔茶枯萎病相关的 Phomopsis 物种。对分离物进行了内部转录间隔区（ITS1、5.8S、ITS2）和翻译延伸因子-1α基因部分序列的 DNA 序列比较。此外，还在温室接种试验中对 8 个月大的盆栽植物进行了比较，以评估其致病性。鉴定出了 5 个物种，其中 D. aspalathi（以前被鉴定为 D. phaseolorum 或 D. phaseolorum var. meridionalis）是最毒的，其次是 D. ambigua、Phomopsis theicola、Libertella 的一个种和 Phomopsis，以及一个新描述的种 P. cuppatea。还根据新指定的模式标本对 D. ambigua 进行了描述。
