SCIENtIfIC RePoRTS | 7: 16578 | DOI:10.1038/s41598-017-16871-8
High throughput deep sequencing
reveals the important roles of
microRNAs during sweetpotato
storage at chilling temperature
, Aiming Wang
, Hongmin Li
, Jingjing Yu
, Jiaojiao Jiang
, Zhonghou Tang
, Baohong Zhang
, Yonghua Han
& Zongyun Li
Sweetpotato (Impomoea batatas L.) is a globally important economic food crop with a potential of
becoming a bioenergy and pharmaceutical crop. Thus, studying the molecular mechanism of tuberous
root development and storage is very important. However, not too much progress has been made
in this eld. In this study, we employed the next generation high-throughput deep sequencing
technology to sequence all small RNAs and degradome of sweetpotato for systematically investigating
sweetpotato response to chilling stress during storage. A total of 190 known microRNAs (miRNAs)
and 191 novel miRNAs were identied, and 428 transcripts were targeted by 184 identied miRNAs.
More importantly, we identied 26 miRNAs dierentially expressed between chilling stress and
control conditions. The expression of these miRNAs and their targets was also conrmed by qRT-
PCR. Integrated analysis of small RNAs and degradome sequencing reveals that miRNA-mediated SA
signaling, ABA-dependent, and ROS response pathways are involved in sweetpotato root response to
chilling stress during storage.
Sweetpotato (Ipomoea Batatas Lam.) is a hexaploid (2n = 6x = 90) dicot in the Convolvulaceae family. Due to its
rich nutritional characteristics, unuctuating high yields, and worldwide adaptability, it is used as nourishment,
animal feed, and a raw material for biofuel production. With origin in the tropics, sweetpotato is susceptible
to chilling damage when stored at low temperatures. Chilling damage may occur in many dierent situations,
including on-farm storage and in consumer refrigerators; it also happens in wholesale and retail storage facilities
and in supermarket display racks as well as during transportation. Long-term exposure to low temperature results
in a series of physiological changes, including vacuolar membrane degradation, mitochondrial membrane swell-
ing, and an increased content of phenolic compounds in sweetpotato roots
. In China, about 1/3 of sweetpotato
yield is aected by low-temperature storage stress, and further reducing yield and utilization. us identifying the
factors responsible in this stress response would have a signicant economic impact. In the past, although people
attempted to solve this problem, the majority of studies focused on optimizing storage conditions; there are also
several reports on the physiological and molecular changes in sweetpotato during cold storage stress. However,
the regulatory mechanism is unclear.
MicroRNAs (miRNAs), a type of widespread non-coding small endogenous RNA ranging from approximately
20 to 24 nucleotides in length, are a crucial negative regulator in the post-transcriptional gene regulation, which
regulate gene expression by targeting mRNAs for translational repression and/or guiding degradation of their
. miRNAs are widely existed throughout the entire plant kingdom and are highly conserved from
plant species to species, such as from mosses to higher owering plants, including both monocots and dicots
Numerous reports show that miRNAs are involved in plant growth and development as well as response to
Institute of Integrative Plant Biology, School of Life Science, Jiangsu Normal University, Xuzhou, China.
Key Laboratory of Phylogenomics and Comparative Genomics, Jiangsu Normal University, Xuzhou, China.
Institute of Agricultural Sciences in Xuhuai Distrct, Jiangsu Xuzhou Sweetpotato Research Center, Sweetpotato
Research Institute, CAAS, Xuzhou, China.
Key Laboratory of Biology and Genetic Improvement of Sweetpotato,
Ministry of Agriculture, Xuzhou, China.
Department of Biology, East Carolina University, Greenville, NC, USA.
Zeyi Xie and Aiming Wang contributed equally to this work. Correspondence and requests for materials should be
addressed to Y.H. (email: email@example.com) or Z.L. (email: firstname.lastname@example.org)
Received: 10 July 2017
Accepted: 6 November 2017
Published: xx xx xxxx