Abstract

Southern corn rust, caused by Puccinia polysora, is a yield-limiting disease on corn (Zea mays). As a biotrophic fungal pathogen, P. polysora requires a living host for its survival. Southern corn rust is favoured by high-temperatures and humid environmental conditions, and therefore is more prevalent in the southern United States. In August 2020, corn plants displaying signs and symptoms of southern rust were collected in a field in Grand Forks County, North Dakota. Due to its rare occurrence in the region, spores of the pathogen were isolated and analyzed morphologically, and found to be consistent with P. polysora. This identification was confirmed by PCR analysis and Sanger sequencing, and demonstrated further using Koch’s postulates. The discovery of P. polysora poses a potential threat to corn yields across North Dakota, and surveillance must be enhanced to predict possible epidemics in the future.

摘要

由Puccinia polysora引起的南方玉米锈病是一种限制玉米 ( Zea mays )产量的病害。作为一种生物营养性真菌病原体，多肉孢霉需要一个活宿主才能生存。南方玉米锈病受高温和潮湿环境条件的青睐，因此在美国南部更为普遍。2020 年 8 月，在北达科他州大福克斯县的一个田地里收集了表现出南方锈病迹象和症状的玉米植株。由于其在该地区的罕见发生，病原体的孢子被分离出来并进行形态学分析，发现与多肉孢子菌一致. 该鉴定通过 PCR 分析和 Sanger 测序得到证实，并使用 Koch 假设进一步证明。P. polysora的发现对整个北达科他州的玉米产量构成了潜在威胁，必须加强监测以预测未来可能的流行病。