Rashed Arash, Workneh Fekede, Paetzold Li, Rush Charles M
University of Idaho, Aberdeen R&E Center, Aberdeen 83210, and Texas A&M AgriLife Research and Extension Center, Amarillo 79109.
Texas A&M AgriLife Research and Extension Center, Amarillo.
Plant Dis. 2015 Feb;99(2):274-280. doi: 10.1094/PDIS-04-14-0421-RE.
Zebra chip (ZC) is a disease of potato, putatively caused by the vectorborne bacterium 'Candidatus Liberibacter solanacearum'. Although ZC has been a major concern due its significant negative impact on both potato yield and quality, its effect on seed potato sprouting has been the subject of recent evaluations. The present study was conducted to determine whether variation in emergence is affected by the infection duration of 'Ca. L. solanacearum'-infected seed potato prior to harvest. Furthermore, changes in pathogen detectability and titer levels in late-season-infected plants also were evaluated during and after cold storage. The rate of ZC-affected seed potato emergence following cold storage was not affected by the time of infection in the field, and the majority of ZC-infected tubers failed to sprout. Time to "seedling" emergence also was significantly longer in seed potato from plants infected ≥2 weeks before harvest. The small percentage of plants that emerged from ZC-affected seed potato produced stunted, nonvigorous plants that often died after a few weeks. The rate of successful 'Ca. L. solanacearum' detection increased during cold storage, suggesting a continued 'Ca. L. solanacearum'-tuber interaction postharvest. After tubers were removed from cold storage and held at room temperature, 'Ca. L. solanacearum' titer started to increase. Although none of the tubers from plants infected 1 week before harvest exhibited any disease symptoms or tested positive for 'Ca. L. solanacearum' at harvest, up to 38% of these tubers tested positive following placement at room temperature after cold storage. Results of this study suggest that the role of seedborne ZC in disease epidemiology is likely to be insignificant. Furthermore, the findings of this study emphasized the importance of continued control measures until at least a week before harvest, and highlighted the need for improved methods of 'Ca. L. solanacearum' detection at harvest, especially in tubers infected late in the season.
斑马薯片病（ZC）是马铃薯的一种病害，据推测由媒介传播细菌“番茄伪菌 Liberibacter solanacearum”引起。尽管由于斑马薯片病对马铃薯产量和品质均有重大负面影响，一直备受关注，但其对种薯发芽的影响仍是近期评估的主题。本研究旨在确定收获前“番茄伪菌 Liberibacter solanacearum”感染种薯的持续时间是否会影响出苗差异。此外，还评估了冷藏期间及冷藏后晚季感染植株中病原体可检测性和滴度水平的变化。冷藏后受斑马薯片病影响的种薯出苗率不受田间感染时间的影响，且大多数受斑马薯片病感染的块茎未能发芽。收获前≥2周感染植株的种薯，其“幼苗”出苗时间也显著更长。从受斑马薯片病影响的种薯中出苗的植株比例很小，所长出的植株发育不良、生长不旺盛，通常几周后就会死亡。冷藏期间，成功检测到“番茄伪菌 Liberibacter solanacearum”的比率增加，这表明收获后“番茄伪菌 Liberibacter solanacearum”与块茎仍持续相互作用。将块茎从冷藏中取出并置于室温后，“番茄伪菌 Liberibacter solanacearum”滴度开始上升。尽管收获前1周感染植株的块茎在收获时均未表现出任何病害症状或检测出“番茄伪菌 Liberibacter solanacearum”呈阳性，但冷藏后置于室温下，这些块茎中高达38%检测呈阳性。本研究结果表明，种传斑马薯片病在病害流行病学中的作用可能微不足道。此外，本研究结果强调了至少在收获前一周持续采取控制措施的重要性，并突出了改进收获时“番茄伪菌 Liberibacter solanacearum”检测方法的必要性，尤其是对于季末感染的块茎。
