Grey leaf spot is a serious yield-reducing disease of maize (Zea mays) in many parts of the world where this crop is cultivated. The causal organism associated with the disease is Cercospora zeae-maydis. Two potential sibling species have been recognized as Groups I and II. The DNA sequences for the internal transcribed spacers (ITS1 & ITS2), the 5.8S rRNA gene, elongation factor 1-alpha, histone H3, actin and calmodulin gene regions suggest that Groups I and II are two distinct species. Furthermore, Cercospora zeae-maydis (Group I) can be distinguished from C. zeina sp. nov. (Group II) by its faster growth rate on artificial media, the ability to produce cercosporin, longer conidiophores, and broadly fusiform conidia. A PCR-based test that distinguishes the two species was developed using species-specific primers designed from the histone H3 gene.

中文翻译：

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与玉米灰斑病相关的尾孢属物种。

在世界许多种植这种作物的地区，灰叶斑病是玉米 (Zea mays) 的严重减产病害。与该疾病相关的致病微生物是玉米尾孢。两个潜在的同胞物种已被确认为组 I 和 II。内部转录间隔区（ITS1 和 ITS2）、5.8S rRNA 基因、延伸因子 1-α、组蛋白 H3、肌动蛋白和钙调蛋白基因区域的 DNA 序列表明，I 组和 II 组是两个不同的物种。此外，Cercospora zeae-maydis（I 组）可以与 C. zeina sp. 区分开来。十一月 （第 II 组）因其在人工培养基上的更快生长速度、产生尾孢菌素的能力、更长的分生孢子和广泛的梭形分生孢子。