JIA-2019-11

Journal of Integrative Agriculture 2019, 18(11): 2549–2560 RESEARCH ARTICLE Available online at www.sciencedirect.com ScienceDirect Molecular, serological and biological characterization of a novel Apple stem pitting virus strain from a local pear variety grown in China LI Liu 1, 2* , ZHENG Meng-meng 1, 2* , MA Xiao-fang 2 , LI Yuan-jun 3 , LI Qing-yu 3 , WANG Guo-ping 1, 2 , HONG Ni 1, 2 1 State Key Laboratory of Agromicrobiology, Huazhong Agricultural University, Wuhan 430070, P.R.China 2 Key Laboratory of Crop Disease Monitoring and Safety Control in Hubei Province, College of Plant Science and Technology, Huazhong Agricultural University, Wuhan 430070, P.R.China 3 Yantai Academy of Agricultural Science, Yantai 264000, P.R.China Abstract Apple stem pitting virus (ASPV) is an important causal agent of pear diseases. Nowadays, the infection status and molecular characteristics of the virus in old pear trees have never been investigated. In this study, we provide the first complete genome sequence of an ASPV isolate LYC from an over 300-year-old tree of a local Pyrus bretschneideri cultivar ‘Chili’ specifically grown at Laiyang area in China. ASPV-LYC possesses a chimeric genome consisting of 9 273 nucleotides excluding a poly(A) tail at its 3´ end and harboring a recombination region in its open reading frame (ORF1) with Aurora-1 and KL9 identified as the major and minor parents. Western blot analysis with antisera against recombinant coat proteins (CPs) of three ASPV isolates from pear indicates that ASPV-LYC is serologically related to these ASPV isolates, but with differential activities. Further biological tests on indicator plants of Pyronia veitchii show that ASPV-LYC can induce serious leaf and stem symptoms as other ASPV isolates. The results provide an important information for understanding molecular evolution of ASPV and suggest a need to prevent dissemination of the isolate among pear trees. Keywords: pear, apple stem pitting virus, genome, Western blot 1. Introduction Apple stem pitting virus (ASPV) is a common virus of apple and pear worldwide (Nemeth 1986; Sutic et al . 1999). Recently, ASPV infection in cherry and sour cherry in India has been reported (Dhir et al . 2010). The virus infection in apple and most pear trees is usually asymptomatic. However, the virus infection can induce leaf vein yellowing (Jelkmann 1994) and red mottling (Desvignes et al . 1999) or necrotic spot (Kishi et al . 1976) and fruit stony pits on susceptible pear trees (Paunovic et al . 1999). The virus is also associated with quince ( Cydonia oblonga ) fruit deformation disease (Mathioudakis et al . 2006, 2009). Additionally, ASPV induces xylem pits in the stem of Malus Received 25 September, 2018 Accepted 10 January, 2019 LI Liu, E-mail: 15032210591@163.com; ZHENG Meng-meng, E-mail: 862238980@qq.com; Correspondence HONG Ni, Tel: +86-27-87281096 , Fax: +86-27-87384670, E-mail: whni@mail. hzau.edu.cn * These authors contributed equally to this study. © 2019 CAAS. Published by Elsevier Ltd. This is an open access article under the CC BY-NC-ND license (http:// creativecommons.org/licenses/by-nc-nd/4.0/) . doi: 10.1016/S2095-3119(19)62636-5