Molecular characterization and phylogenetic analysis of hop stunt viroid isolates from sweet cherry in China

Authors: XU, LI - Shandong Academy Of Agricultural Sciences; WANG, JIAWEI - Shandong Academy Of Agricultural Sciences; CHEN, XIN - Shandong Academy Of Agricultural Sciences; ZHU, DONGZI - Shandong Academy Of Agricultural Sciences; WEI, HAIRONG - Shandong Academy Of Agricultural Sciences; Hammond, Rosemarie; LIU, QINGZHONG - Shandong Academy Of Agricultural Sciences

Submitted to: European Journal of Plant Pathology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 2/5/2019
Publication Date: 2/15/2019
Citation: Xu, L., Wang, J., Chen, X., Zhu, D., Wei, H., Hammond, R., Liu, Q. 2019. Molecular characterization and phylogenetic analysis of hop stunt viroid isolates from sweet cherry in China. European Journal of Plant Pathology. https://doi.org/10.1007/s10658-019-01693-3.
DOI: https://doi.org/10.1007/s10658-019-01693-3

Interpretive Summary: Sweet cherry (Prunus avium L.) is an important economic fruit crop worldwide, including the United States. Infection of sweet cherry trees with hop stunt viroid (HSVd) is associated with severe symptoms, such as dappled fruit, which renders the fruits unmarketable. Control of the disease relies on the planting of HSVd-free material for which knowledge of nucleotide sequence variants impacts sensitive detection methods. There is limited information on the nucleotide sequence variability among HSVd sweet cherry isolates and their relationships to HSVd isolates from additional plant species, including hop, grapevines and other tree fruits. In this study, several sequence variants were identified and characterized from symptomatic sweet cherry orchards in China and were shown to be related to isolates from other plant hosts and geographic regions. The presence of HSVd in sweet cherry trees in China has implications for the movement of plant material between continents and the unintentional distribution of viroid isolates worldwide. This report will of interest to an international audience of researchers in industry, academia, and government organizations with an interest in plant pathology and control of fruit tree diseases.

Technical Abstract: Hop stunt viroid (HSVd), a member of the family Pospiviroidae, infects many plants and causes substantial economic losses. In this study, HSVd was detected in dappled fruits of sweet cherry and then molecularly characterized. We sequenced 164 cDNA clones from six sweet cherry cultivars in the Shandong Province of China and identified 23 HSVd sequence variants, which ranged in size between 293 and 303 nucleotides (nt) and shared 97~99% sequence identity with each other. Characterization of HSVd variants revealed that three were predominant in sweet cherry trees. Phylogenetic analysis showed that most of the HSVd variants isolated from sweet cherry were clustered within the plum-type group and that two variants were clustered with the recombinant P-C group, regardless of geographic origin. This study identified 23 HSVd variants and provided the molecular characterization of viroid infection (HSVd) in sweet cherry in China.