Bae J, Atallah Z K, Jansky S H, Rouse D I, Stevenson W R
Department of Horticulture, University of Wisconsin-Madison, 53706.
Department of Plant Pathology, University of Wisconsin-Madison, 53706.
Plant Dis. 2007 Sep;91(9):1137-1141. doi: 10.1094/PDIS-91-9-1137.
Potato early dying (PED), caused by Verticillium dahliae, is a chronic yield-limiting disease of potato (Solanum tuberosum). In this study, we describe the colonization dynamics of V. dahliae in two potato cultivars with varying responses to PED. We utilized a quantitative real-time polymerase chain reaction (Q-PCR) assay to assess the colonization and spatial progression of V. dahliae in cvs. Ranger Russet (moderately resistant) and Russet Norkotah (highly susceptible). Ninety plants per cultivar were inoculated with a conidial suspension in the greenhouse. Every 2 weeks until week 10, we collected basal samples from 15 plants, and repeatedly sampled the growing apices of another 15 plants. The mean infection coefficient (IC) values in the basal and apical samples were significantly lower in cv. Ranger Russet at all five sampling dates. The pathogen was detected in basal samples of both cultivars by week 2, and in apical samples of cv. Russet Norkotah at week 4 and of cv. Ranger Russet at week 6. Colonization of cv. Russet Norkotah consistently increased in apical and basal samples during the 10 weeks, while it plateaued after week 6 in cv. Ranger Russet. Differences in response to PED appear associated with the speed of colonization and the establishment of a higher population density by V. dahliae in the plant.
由大丽轮枝菌引起的马铃薯早死病（PED）是马铃薯（Solanum tuberosum）一种导致产量长期受限的病害。在本研究中，我们描述了大丽轮枝菌在两个对PED有不同反应的马铃薯品种中的定殖动态。我们利用定量实时聚合酶链反应（Q-PCR）分析来评估大丽轮枝菌在品种Ranger Russet（中度抗病）和Russet Norkotah（高度感病）中的定殖情况和空间扩展。在温室中，每个品种用分生孢子悬浮液接种90株植株。在第10周之前，每2周我们从15株植株上采集基部样本，并对另外15株植株的生长顶端进行重复采样。在所有五个采样日期，品种Ranger Russet基部和顶端样本中的平均感染系数（IC）值均显著较低。到第2周时，在两个品种的基部样本中均检测到病原体，在第4周时在Russet Norkotah品种的顶端样本中检测到病原体，在第6周时在Ranger Russet品种的顶端样本中检测到病原体。在10周内，Russet Norkotah品种在顶端和基部样本中的定殖持续增加，而Ranger Russet品种在第6周后趋于平稳。对PED反应的差异似乎与定殖速度以及大丽轮枝菌在植物中建立更高种群密度有关。
