Identification and Characterization of a Pear Chlorotic Leaf Spot-Associated Virus, a Novel Emaravirus Associated with a Severe Disease of Pear Trees in China
Huazhen Liu, Guoping Wang, Zuokun Yang, Yanxiang Wang, Zhe Zhang, Longhui Li, Muhammad Waqas, Ní Hóng, Huazhen Liu, Guoping Wang, Ní Hóng, Jian Hong, Jinguo Zhang, Lei Xu, Liying Qi
Abstract
Pear chlorotic leaf spot (PCLS) is a recently emerged disease of commercially cultivated sandy pear (Pyrus pyrifolia) trees in central and southern China. By integrating high-throughput sequencing and conventional Sanger sequencing of reverse-transcription (RT)-PCR products, a novel emaravirus infecting pear trees was identified and molecularly characterized. The virus was provisionally named pear chlorotic leaf spot-associated virus (PCLSaV). PCLSaV shows the typical molecular features of members of the genus Emaravirus in the family Fimoviridae. It has a genome composed of at least five negative-sense RNA segments, with each containing a single open reading frame and two complementary 13-nucleotide stretches at the 5′ and 3′ termini. PCLSaV shows a close phylogenetic relationship with recognized emaraviruses but forms a separate clade. Moreover, double-membrane-bound bodies were observed in PCLSaV-infected tissues and in extracts of PCLSaV-infected leaves. For the first time, our study revealed the profile distribution of viral RNA reads from the RNA-seq libraries of three samples along the RNA1 to RNA5 of an emaravirus. Field surveys combined with specific RT-PCR assays revealed the presence of PCLSaV in almost all PCLS-diseased pear samples, strongly supporting the association of the virus with the PCLS disease. This study revealed the first emaravirus infecting pear trees and its association with a severe pear chlorotic leaf disease.