First Report of Southern Rust ( Puccinia polysora ) on Corn ( Zea mays ) in Michigan
First Report of Southern Rust ( Puccinia polysora ) on Corn ( Zea mays ) in Michigan
复制标题
密歇根州玉米（Zea mays）上首次报道南方锈菌（Puccinia polysora）
DOI：
10.1094/pdis-11-21-2569-pdn
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发表时间：
2022
期刊：
影响因子：
4.5
通讯作者：
Chilvers, M. I.
中科院分区：
文献类型：
--
作者：
Check, J. C.;Aime, M. C.;Byrne, J. M.;Chilvers, M. I.
在密歇根州，玉米 (Zea mays) 种植面积达 235 万英亩，年产值达 13.6 亿美元（USDA-NASS 2021）。南方锈病是由专性生物营养真菌 Puccinia polysora Underw 引起的。在美国南部，它经常被列为最具破坏性的前五名玉米病害（Mueller 等人，2020 年）。美国北部南部锈病造成的产量损失相当可观，2016 年至 2019 年估计达 2.31 亿蒲式耳。2020 年和 2021 年，从密歇根州各地的商业生产田采集了表现出典型 P. polysora 感染迹象的玉米叶样本。 2020 年，从布兰奇县和希尔斯代尔两个县采集了样本。 2021 年，我们从另外 10 个县采集了样本：阿勒根县、巴里县、卡尔霍恩县、伊顿县、英厄姆县、肯特县、蒙卡尔姆县、夏瓦西县、图斯科拉县和范布伦县。观察到P. polysora 的Uredinia 主要聚集在叶上表面，呈浅肉桂棕色至亮橙色，卵形，周围有黄色光环。在40倍光学显微镜下观察，核孢子中心呈黄色至金色，外膜透明，椭圆形至倒卵圆形，表面有短刺状突起。孢子 (n= 180) 尺寸为 17 至 28× 26 至 38 µm。没有观察到telia。为了确认鉴定，按照 Aime (2006) 和 Aime 等人 (2018) 中所述，对 2021 年从 Shiawassee 县采集的样本进行了扩增，并使用 rust 特异性引物对大亚基 (28S) rDNA 进行了测序。所得 DNA 序列（GenBank 登录号 OL468037）与 P. polysora 凭证 BPI 具有 99.79% 的同一性（932/934 bp） 863756（GenBank 登录号 GU058024）（Dixon 等人，2010）。这份报告是密歇根州南部锈病的第一份记录，也是对其在全州分布的初步调查。由于 P. polysora 孢子能够通过风长距离传播（Cammack 1959），因此该疾病很可能存在，但在本报告未包括的其他县中未检测到。尽管密歇根州尚未有因南方锈病造成大范围产量损失的记录，但有传闻称，谷物玉米每英亩损失 30 蒲式耳，青贮饲料田吨位损失 30%。了解南方锈菌的分布有助于为未来的疾病管理和玉米育种研究提供信息。此外，由于全球气温升高，预计到 2100 年，南方锈菌的分布将向极地移动 15 倍（Ramirez-Cabral 等人，2017 年），并且应记录南方锈菌向北方玉米种植区的移动。其他确认有南部锈病的密歇根州县将继续通过玉米 IPMpipe (https://corn.ipmpipe.org/) 进行报告。
In Michigan, corn (Zea mays) is grown on 2.35 million acres with an annual production valued at $1.36 billion (USDA-NASS 2021). Southern rust is caused by the obligate biotrophic fungus Puccinia polysora Underw. and is often ranked in the top five most destructive corn diseases in the southern United States (Mueller et al. 2020). Yield losses due to southern rust in the northern United States have been considerable and estimated to be 231 million bushels from 2016 to 2019. In 2020 and 2021, corn leaf samples exhibiting signs typical of infection by P. polysora were collected from commercial production fields across Michigan. In 2020, samples were collected from two counties, Branch and Hillsdale. In 2021, samples were collected from 10 additional counties: Allegan, Barry, Calhoun, Eaton, Ingham, Kent, Montcalm, Shiawassee, Tuscola, and Van Buren. Uredinia of P. polysora were observed aggregated primarily on the upper leaf surface and were light cinnamon brown to bright orange, ovular, and surrounded by yellow halos. Urediniospores were yellow to gold in the center, hyaline along the outer membrane, ellipsoid to obovoid, and with short echinulations on the surface when viewed at 40× magnification under a light microscope. Urediniospores (n= 180) measured 17 to 28× 26 to 38 µm. No telia were observed. To confirm identification, the large subunit (28S) rDNA was amplified and sequenced with rust specific primers as described in Aime (2006) and Aime et al.(2018) on a sample collected from Shiawassee County in 2021. The resulting DNA sequence (GenBank accession no. OL468037) shared 99.79% identity (932/934 bp) with P. polysora voucher BPI 863756 (GenBank accession no. GU058024)(Dixon et al. 2010). This report serves as the first documentation of southern rust in Michigan and an initial survey of its distribution throughout the state. Because of the ability of P. polysora spores to travel long distances via wind (Cammack 1959), it is likely that the disease was present but not detected in additional counties not included in this report. Although widespread yield losses due to southern rust have not been documented in Michigan, there have been anecdotal reports of 30 bushels per acre losses in grain corn and 30% loss of tonnage from silage fields. Understanding the distribution of southern rust can help inform future disease management and corn breeding research. Furthermore, the distribution of southern rust is projected to move poleward by 15 by 2100 due to increasing global temperatures (Ramirez-Cabral et al. 2017), and the movement of southern rust into northern corn growing regions should be documented. Additional Michigan counties with confirmations of southern rust will continue to be reported via the corn IPMpipe (https://corn. ipmpipe. org/).