Occurrence and genetic diversity analysis of apple stem pitting
virus isolated from apples in China
Received: 9 February 2017 / Accepted: 19 March 2017 / Published online: 25 April 2017
Ó Springer-Verlag Wien 2017
Abstract Two primer pairs were used to detect apple stem
pitting virus (ASPV) using a reverse transcription (RT)-
PCR test. 82 out of the 141 randomly collected samples,
from ten orchards in ﬁve provinces and regions of China,
tested positive. In the positive samples forty-ﬁve (55%)
were infected by ASPV and two other viruses. The full coat
protein (CP) and the triple gene block (TGB) gene 1, 2 and
3 of partial ASPV isolates were subsequently cloned. The
nucleotide and amino acid identities of 39 CP sequence
variants from 31 Chinese apple samples were compared
with that of previously reported ASPV isolates and were
67.4–96.0% and 68.4–97.7%, respectively. All ASPV
sequence variants from Chinese apples separated into two
clades with CP- and TGB-based phylogenetic trees, whilst
the grouping of TGB2 and TGB3 trees was the same. Three
recombinants (FS06-2, X5-2, and XLF-C-2) for CP and six
(TH2-5, X8-2, FS05-2, X6-2 and XLF-A-1) recombinants
for TGB were identiﬁed from the Chinese apple isolates.
Two recombinants were found in the TGB sequence of
isolate XLF-A-1. The results presented here may assist in
the development of a more comprehensive screening tool
for apple viruses.
Apple (Malus domestica) is one of the most widely grown
fruit trees in the world. China is one of the main apple-
producing countries, with a planting area of 2.3 million
hectares (ha) and 41 million tons of fruit produced in 2014.
In fact China produces almost half of the world’s apples.
Many fruit trees, like apple, that are produced via vegeta-
tive propagation are particularly susceptible to viruses that
are transmitted from generation to generation. In com-
mercially cultivated apple trees, apple mosaic virus
(ApMV, genus Ilarvirus, family Bromoviridae), apple
chlorotic leaf spot virus (ACLSV, genus Trichovirus,
family Betaﬂexiviridae), apple stem pitting virus (ASPV,
genus Foveavirus, family Betaﬂexiviridae), apple stem
grooving virus (ASGV, genus Capillovirus, family
Betaﬂexiviridae), and apple scar skin viroid (ASSVd) are
common pathogens, except in a handful of resistant vari-
ASPV has a worldwide distribution in pome fruit trees.
It is transmitted mechanically to a limited herbaceous host
range and has no known vector . ASPV is a latent virus
of apple and pear that often remains asymptomatic yet may
result in growth reduction and yield losses [11, 22].
Symptoms comprise xylem pits in the stem of ‘Virginia
crab’ and epinasty and decline of ‘Spy 277’ cultivar .
Pear vein yellow disorders, stony pit disease, and necrotic
spots are induced by certain ASPV strains in various pear
cultivars . Sooty ring spot and fruit deformation in
quince have also been associated with ASPV infection
. ASPV frequently occurs in combination with other
latent viruses such as ACLSV and ASGV. This co-infec-
tion is the main cause of a decrease in fruit yield quality
and quantity. Yield reductions for apple production
reported in the literature vary from 12.0% to 67.0%
[3, 24, 31], which leads to tremendous economic losses.
The genome of ASPV is a single-stranded positive-sense
RNA and the virus particles are ﬂexible ﬁlaments that are
12–15 nm wide and 800 nm long. The genome comprises
Electronic supplementary material The online version of this
article (doi:10.1007/s00705-017-3384-3) contains supplementary
material, which is available to authorized users.
& Ya-Feng Dong
Research Institute of Pomology, Chinese Academy of
Agricultural Sciences, Xingcheng 125100, PR China
Arch Virol (2017) 162:2397–2402