Xiao Huogen, Hao Wenjia, Storoschuk Gavin, MacDonald Jesse L, Sanfaçon Hélène
Summerland Research and Development Centre, Agriculture and Agri-Food Canada, Summerland, BC V0H 1Z0, Canada.
Pathogens. 2022 Oct 25;11(11):1231. doi: 10.3390/pathogens11111231.
Rapid apple decline disease (RAD) has been affecting orchards in the USA and Canada. Although the primary cause for RAD remains unknown, viruses may contribute to the incidence or severity of the disease. We examined the diversity and prevalence of viruses in orchards affected by RAD in the Okanagan and Similkameen Valleys (British Columbia, Canada). Next-generation sequencing identified 20 previously described plant viruses and one viroid, as well as a new ilarvirus, which we named apple ilarvirus 2 (AIV2). AIV2 was related to subgroup 2 ilarviruses (42-71% nucleotide sequence identity). RT-PCR assays of 148 individual leaf samples revealed frequent mixed infections, with up to eight viruses or viroid detected in a single tree. AIV2 was the most prevalent, detected in 64% of the samples. Other prevalent viruses included three ubiquitous viruses from the family and citrus concave gum-associated virus. Apple rubbery wood virus 1 and 2 and apple luteovirus 1 were also readily detected. The thirteen most prevalent viruses/viroid were detected not only in trees displaying typical RAD symptoms, but also in asymptomatic trees. When compared with reports from orchards affected by RAD in Pennsylvania, New York State, and Washington State, regional differences in relative virus prevalence were noted.
快速苹果衰退病（RAD）一直在影响美国和加拿大的果园。尽管RAD的主要病因仍然不明，但病毒可能与该病的发病率或严重程度有关。我们调查了加拿大不列颠哥伦比亚省奥肯那根谷和西米卡米恩谷受RAD影响果园中病毒的多样性和流行情况。新一代测序鉴定出20种先前描述的植物病毒和一种类病毒，以及一种新的等轴不稳环斑病毒，我们将其命名为苹果等轴不稳环斑病毒2（AIV2）。AIV2与第2亚组等轴不稳环斑病毒相关（核苷酸序列同一性为42%-71%）。对148个单叶样本进行的逆转录聚合酶链反应分析显示频繁发生混合感染，在单棵树中检测到多达8种病毒或类病毒。AIV2最为普遍，在64%的样本中被检测到。其他普遍存在的病毒包括来自该科的三种普遍存在的病毒以及柑橘凹皮病相关病毒。苹果橡胶木病毒1和2以及苹果黄化病毒1也很容易被检测到。这13种最普遍的病毒/类病毒不仅在表现出典型RAD症状的树木中被检测到，也在无症状的树木中被检测到。与宾夕法尼亚州、纽约州和华盛顿州受RAD影响果园的报告相比，注意到了病毒相对流行率的区域差异。
