Pereskia aculeata, commonly known as ora-pro-nobis, is a is a highly nutritive species used for human consumption with potential of expansion. However, leaf lesions that did not match the symptoms and signs of previously described pathogenic species to this culture were observed in an ora-pro-nobis cultivation in Curitiba, Paraná state, southern Brazil. Therefore, the objectives of this study were to isolate, test the pathogenicity and characterize morphologically and molecularly the causal agent of the symptoms of this species. For this purpose, isolation from leaf fragments was performed. Pathogenicity was tested in potted cuttings which were wounded to simulate the thorns natural injuries and inoculated with a conidia suspension. The colony characteristics and morphological features of conidia were determined on V8 medium, and the molecular characterization was performed with Bayesian phylogenetic inference of the partial concatenated alignment of the ITS, gapdh and tef1 genes of the isolate. Morphological characterization matched the described for Alternaria spp. The symptoms on inoculated cuttings appeared within 4 days in all inoculated leaves, while the control plants remained asymptomatic, and 10 days after inoculation all symptomatic leaves fell from the plant. The characteristics of the re-isolated fungus from the pathogenicity test lesions were morphologically similar to the isolate from naturally infected leaves. The sequences of the pathogen grouped in a reliable clade called Alternaria arborescens. To our knowledge, this is the first report of A. arborescens causing lesions on P. aculeata worldwide. Implications of these finding should be further studied.

Pereskia aculeata,通常被称为ora-pro-nobis，是一种用于人类消费的高营养物种，具有扩展潜力。然而，在巴西南部巴拉那州库里提巴的 ora-pro-nobis 种植中观察到与先前描述的病原物种的症状和体征不匹配的叶病灶。因此，本研究的目的是分离、测试致病性并在形态学和分子学上表征该物种症状的病因。为此，进行了从叶片段的分离。在模拟荆棘自然损伤并接种分生孢子悬浮液的盆栽插枝中测试致病性。在V8培养基上测定分生孢子的菌落特征和形态特征，分离株的gapdh和tef1基因。形态特征与链格孢属的描述相匹配。所有接种叶片在接种插条上的症状在 4 天内出现，而对照植物保持无症状，接种后 10 天所有有症状的叶片都从植物上脱落。从致病性试验病斑中重新分离出的真菌的特征在形态学上与从自然感染的叶片中分离出的真菌相似。病原体的序列分组在一个可靠的进化枝中，称为Alternaria arborescens。据我们所知，这是A的第一份报告。 arborescens在P上引起病变。 刺状全世界。应进一步研究这些发现的含义。