Plant Pathology & Plant-Microbe Biology Section, School of Integrative Plant Science, Cornell AgriTech at the New York State Agricultural Experiment Station, Cornell University, Geneva, NY 14456, U.S.A.
Phytopathology. 2020 Apr;110(4):943-951. doi: 10.1094/PHYTO-11-19-0412-R. Epub 2020 Mar 2.
and are important pathogens of table beet, sugar beet, and Swiss chard ( subsp. ), causing Cercospora leaf spot (CLS) and Phoma leaf spot, root rot, and damping-off, respectively. Both pathogens may be seedborne; however, limited evidence is available for seed infestation by . Due to the limitations of culture-based seed assessment methods, detection of these pathogens was investigated using PCR. A -specific quantitative PCR assay was developed and used in conjunction with a -specific assay to assess the presence of pathogen DNA in 12 table beet seed lots. DNA of and was detected in four and eight seed lots, respectively. Plate tests and BIO-PCR confirmed the viability of each pathogen; however, competitive growth of other microbes and low incidence limited the frequency and sensitivity of detection in some seed lots. The results for support previously described infestation of seed. Further investigation of -infested seed lots indicated the ability of seedborne to cause CLS on plants grown from infested seed. Detection of viable on table beet seed demonstrates the potential for pathogen dispersal and disease initiation via infested seed, and provides valuable insight into the epidemiology of CLS. Surveys of commercial table beet seed are required to determine the frequency and source of seed infestation and its role as primary inoculum for epidemics, and to evaluate the effectiveness of seed treatments.
和 是甜菜、糖甜菜和瑞士甜菜（亚种）的重要病原体，分别引起尾孢叶斑病（CLS）和茎点霉叶斑病、根腐病和猝倒病。两种病原体都可能通过种子传播；然而，关于 侵染种子的证据有限。由于基于培养的种子评估方法的局限性，使用 PCR 研究了这些病原体的检测。开发了一种 -特异性定量 PCR 检测方法，并与 -特异性检测方法结合，用于评估 12 个甜菜种子批中病原体 DNA 的存在。在四个和八个种子批中分别检测到 和 的 DNA。平板试验和 BIO-PCR 证实了每种病原体的活力；然而，其他微生物的竞争生长和低发生率限制了一些种子批中检测的频率和灵敏度。对 的检测结果支持先前描述的种子侵染。对 -侵染种子批的进一步调查表明，种子携带的 能够在受侵染种子种植的植物上引起 CLS。在甜菜种子上检测到有活力的 表明了通过受侵染的种子传播病原体和引发疾病的潜力，并为 CLS 的流行病学提供了有价值的见解。需要对商业甜菜种子进行调查，以确定 种子侵染的频率和来源及其作为流行病初始接种体的作用，并评估种子处理的有效性。
