Corynespora cassiicola isolates display morphological, pathogenic, and ecological diversity, inducing target spot-like diseases in more than 500 hosts worldwide, including tomato and cucumber. Nevertheless, there is a scarce number of studies about the genetic variability of Corynespora isolates in the New World. Here, we characterized a collection of 58 Corynespora isolates from tomatoes and distinct hosts in Brazil and Florida (USA). All isolates were identified as C. cassiicola according to the sequencing information of the internal transcribed spacer (ITS) region of 18S–28S nuclear ribosomal DNA as well as the translation elongation factor 1-alpha (tef-1α) and β-tubulin (tub2) genes. However, intraspecific resolution was observed in phylogenetic analyses according to the geographical and host origin of the isolates. The β-tubulin (tub2) haplotype network was in agreement with phylogenetic analyses, revealing a polyphyletic structure with three well-defined phylogenetic lineages. The concatenated trees (encompassing all three genomic regions) showed superior intraspecific resolution than the individual phylogenetic trees. Thirteen selected C. cassiicola isolates (representing all three phylogenetic lineages) displayed variability in colony morphology (color, texture, growth rate, and shape) and in conidial morphometrics. Three selected C. cassiicola isolates confirmed their pathogenicity to the original hosts and to other plant species. Novel natural and experimental host-pathogen interactions were identified, including cabbage, Commelina benghalensis, eggplant, Eruca sativa, Hibiscus sabdariffa, and melon. The diversity of C. cassiicola isolates indicates that these phylogenetic lineages may represent a complex of closely related species with distinct patterns of host and cultivar-specificity.

Corynespora cassiicola分离株表现出形态、致病和生态多样性，在全球 500 多个宿主中诱发靶点样疾病，包括番茄和黄瓜。然而，关于新大陆棒孢属分离株遗传变异性的研究很少。在这里，我们对来自巴西和佛罗里达（美国）的西红柿和不同宿主的 58株棒状孢子菌进行了鉴定。所有分离株均被鉴定为C. cassiicola根据18S-28S核核糖体DNA的内部转录间隔区（ITS）区域以及翻译延伸因子1-α（tef-1α）和β-微管蛋白（tub2）基因的测序信息。然而，根据分离株的地理和宿主起源，在系统发育分析中观察到种内分辨率。β-微管蛋白 (tub2) 单倍型网络与系统发育分析一致，揭示了具有三个明确系统发育谱系的多系结构。连接的树（包括所有三个基因组区域）显示出比单个系统发育树更好的种内分辨率。十三精选C. cassiicola分离株（代表所有三个系统发育谱系）在菌落形态（颜色、质地、生长速率和形状）和分生孢子形态测量中表现出变异性。三个选定的C. cassiicola分离株证实了它们对原始宿主和其他植物物种的致病性。鉴定了新的天然和实验性宿主-病原体相互作用，包括卷心菜、孟加拉草芥、茄子、Eruca sativa、Hibiscus sabdariffa和甜瓜。C. cassiicola分离株的多样性表明，这些系统发育谱系可能代表了具有不同宿主模式和品种特异性的密切相关物种的复合体。