Department of Plant Pathology, Washington State University, Pullman, USA.
Phytopathology. 2013 Jan;103(1):55-63. doi: 10.1094/PHYTO-04-12-0073-R.
Verticillium dahliae causes Verticillium wilt of potato and can be found in soil associated with potato seed tubers. The purpose of this research was to quantify V. dahliae in soil associated with certified seed tubers and determine if this potential inoculum source is related to disease development in the field. Approximately 68% of seed lots assayed contained V. dahliae-infested soil on seed tuber surfaces (seed tuber soil). Over 82% of seed lots contained V. dahliae in loose seed lot soil obtained from bags and trucks used to transport seed tubers. Most samples contained ≤50 CFU/g but some contained >500 CFU/g. Most isolates (93%) were vegetative compatibility group 4A. Populations of V. dahliae in stem sap increased with increasing inoculum densities in field soils only when V. dahliae concentrations in seed tuber soil were low. High concentrations of V. dahliae in seed tuber soil resulted in greater stem sap colonization when V. dahliae inoculum densities in field soil were low (P < 0.01) and resulted in greater pathogen inoculum densities in postharvest field soils (P = 0.04). Seed tubers contaminated with V. dahliae-infested soils may introduce the pathogen into fields not previously cropped to potato or recontaminate those which have received preplant management practices. Long-term management of V. dahliae requires reducing propagules in soil associated with seed lots.
黄萎轮枝菌可引起马铃薯黄萎病，且可在与马铃薯种薯相关的土壤中发现。本研究的目的是量化与经认证的种薯相关的土壤中黄萎轮枝菌的含量，并确定该潜在接种源是否与田间病害的发展有关。大约 68%的种薯样本在种薯表面（种薯土壤）上含有黄萎轮枝菌污染的土壤。超过 82%的种薯样本在用于运输种薯的袋子和卡车上获得的松散种薯土壤中含有黄萎轮枝菌。大多数样本中含有 ≤50 CFU/g，但有些样本中含有 >500 CFU/g。大多数分离株（93%）为营养体亲和群 4A。仅当种薯土壤中黄萎轮枝菌浓度较低时，田间土壤中黄萎轮枝菌接种密度的增加才会导致茎汁中黄萎轮枝菌种群的增加。种薯土壤中黄萎轮枝菌浓度高时，即使田间土壤中黄萎轮枝菌接种密度低，也会导致茎汁中更大的定植（P < 0.01），并导致收获后田间土壤中病原体接种密度增加（P = 0.04）。受黄萎轮枝菌污染土壤的种薯可能会将病原体引入以前未种植过马铃薯的田地，或重新污染已经接受过种植前管理措施的田地。长期管理黄萎轮枝菌需要减少与种薯相关的土壤中的繁殖体。
