Funke Cassandra N, Nikolaeva Olga V, Green Kelsie J, Tran Lisa T, Chikh-Ali Mohamad, Quintero-Ferrer Arturo, Cating Robert A, Frost Kenneth E, Hamm Philip B, Olsen Nora, Pavek Mark J, Gray Stewart M, Crosslin James M, Karasev Alexander V
Department of Plant, Soil and Entomological Sciences (PSES), University of Idaho, Moscow; and Department of Botany & Plant Pathology, Hermiston Agricultural Research and Extension Center, Oregon State University, Hermiston.
Department of PSES, University of Idaho, Moscow.
Plant Dis. 2017 Jan;101(1):20-28. doi: 10.1094/PDIS-06-16-0901-RE. Epub 2016 Nov 1.
Potato virus Y (PVY) is a serious threat to potato production due to effects on tuber yield and quality, in particular, due to induction of potato tuber necrotic ringspot disease (PTNRD), typically associated with recombinant strains of PVY. These recombinant strains have been spreading in the United States for the past several years, although the reasons for this continuing spread remained unclear. To document and assess this spread between 2011 and 2015, strain composition of PVY isolates circulating in the Columbia Basin potato production area was determined from hundreds of seed lots of various cultivars. The proportion of nonrecombinant PVY isolates circulating in Columbia Basin potato dropped ninefold during this period, from 63% of all PVY-positive plants in 2011 to less than 7% in 2015. This drop in PVY was concomitant with the rise of the recombinant PVY strain incidence, from less than 27% of all PVY-positive plants in 2011 to 53% in 2015. The proportion of the PVY recombinant strain, associated with PTNRD symptoms in susceptible cultivars, increased from 7% in 2011 to approximately 24% in 2015. To further address the shift in strain abundance, screenhouse experiments were conducted and revealed that three of the four most popular potato cultivars grown in the Columbia Basin exhibited strain-specific resistance against PVY. Reduced levels of systemic movement of PVY in such cultivars would favor spread of recombinant strains in the field. The negative selection against the nonrecombinant PVY strain is likely caused by the presence of the Ny gene identified in potato cultivars in laboratory experiments. Presence of strain-specific resistance genes in potato cultivars may represent the driving force changing PVY strain composition to predominantly recombinant strains in potato production areas.
马铃薯Y病毒（PVY）对马铃薯生产构成严重威胁，因为它会影响块茎产量和品质，特别是会引发马铃薯块茎坏死环斑病（PTNRD），这种病通常与PVY的重组菌株有关。在过去几年中，这些重组菌株一直在美国传播，但其持续传播的原因尚不清楚。为了记录和评估2011年至2015年间这种传播情况，从哥伦比亚盆地马铃薯产区数百个不同品种的种薯批次中确定了PVY分离株的菌株组成。在此期间，在哥伦比亚盆地马铃薯中传播的非重组PVY分离株比例下降了九倍，从2011年所有PVY阳性植株的63%降至2015年的不到7%。PVY的这种下降与重组PVY菌株发病率的上升同时发生，从2011年所有PVY阳性植株的不到27%升至2015年的53%。与易感品种中PTNRD症状相关的PVY重组菌株比例从2011年的7%增加到2015年的约24%。为了进一步研究菌株丰度的变化，进行了温室试验，结果表明，在哥伦比亚盆地种植的四个最受欢迎的马铃薯品种中有三个表现出对PVY的菌株特异性抗性。在这些品种中，PVY系统移动水平的降低将有利于重组菌株在田间的传播。对非重组PVY菌株的负选择可能是由于在实验室试验中马铃薯品种中鉴定出的Ny基因的存在。马铃薯品种中存在菌株特异性抗性基因可能是导致马铃薯产区PVY菌株组成向主要为重组菌株转变的驱动力。
