Cassava root rot is a highly destructive disease that causes great damage in Brazil. Identification of the causal agents is essential for the management of this disease. Roots of cassava plants ( Crantz) with symptoms of root rot were collected from a cassava crop in the municipality of Garanhuns, Pernambuco State, Brazil. This study aimed to identify a species isolated from cassava root rot in Brazil and evaluate pathogenicity in cassava plants and roots. At 7 days after inoculation (DAI), tuberous roots showed necrotic lesions, a soft appearance, and pink color in the center and brown to greenish at the edges, while seedlings showed root rot, wilting, yellowing, drying out, and leaf fall at 66 DAI in the soil. All plants in the control group were asymptomatic. After reisolations and confirmation of Koch's postulates, the causal agent was conclusively identified as through the multilocus phylogenetic analyses involving the ITS, , , and genes. The results showed that the morphological characteristics, such as colonies with abundant aerial mycelium, formation of pycnidia and alpha conidia, were consistent with those described for species of the genus . This is the first report of causing cassava root rot in Brazil and worldwide.

中文翻译：

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巴西伯南布哥州的 Diaporthe ueckeri 引起木薯根腐病


木薯根腐病是一种破坏性极强的病害，在巴西造成巨大损失。识别致病因素对于控制这种疾病至关重要。从巴西伯南布哥州加兰洪斯市的木薯作物中采集具有根腐病症状的木薯植物 (Crantz) 的根。本研究旨在鉴定从巴西木薯根腐病中分离出来的物种，并评估木薯植物和根部的致病性。接种后7天(DAI)，块根出现坏死病斑，外观松软，中心呈粉红色，边缘呈棕绿色，幼苗则出现根部腐烂、萎蔫、变黄、干枯、落叶等现象。土壤中 66 DAI。对照组的所有植物均无症状。在重新分离和确认科赫假设后，通过涉及 ITS、 、 和 基因的多位点系统发育分析，最终确定了致病因素。结果表明，菌落气生菌丝丰富、分生孢子器和α分生孢子形成等形态特征与该属物种的描述一致。这是巴西和世界范围内第一份引起木薯根腐病的报告。