High throughput deep sequencing reveals the important roles of microRNAs during sweetpotato storage at chilling temperature

Abstract

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 field. 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 identified, and 428 transcripts were targeted by 184 identified miRNAs. More importantly, we identified 26 miRNAs differentially expressed between chilling stress and control conditions. The expression of these miRNAs and their targets was also confirmed 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.

Integrated transcriptome, small RNA and degradome sequencing approaches proffer insights into chlorogenic acid (CGA) biosynthesis in leafy sweet potato

“…The length distribution of known miRNAs exhibited a peak at 21 nt (Fig. 7b), similar to the results reported in previous research in sweet potato and other species [32][33][34][35]. Reads that could not be mapped to miRBase were subjected to novel miRNA predication by miRDeep2 and the most length distribution of novel miRNA was 24 nt following by 21 nt (Fig.…”

“…miRNAs have emerged as master modulators of gene expression and are promising tools for crop improvement [45]. A few studies in sweet potato had reported the genome-wide discoveries of miRNAs [32][33][34][35], but no study had yet characterized the roles of miRNAs in CGA biosynthesis. In the present study, a total of 149 known and 22 novel miRNAs were identified.…”

“…They negatively regulated expression of their target genes at the post-transcriptional and translational levels and played crucial roles in diverse biological processes, including plant growth and development, viral defence, metabolism and apotosis [31]. Although much progresses had been made in miRNA research in plants, including a few studies in sweet potato [32][33][34][35], the mechanisms of miRNA regulating CGA biosynthesis in leafy sweet potato remained unclear.…”

Antioxidative system in sweet potato rootis activated by low‐temperature storage

“…There are several reports on the physiological and molecular changes occurring during postharvest sweet potato storage, but the endogenous factors contributing to increased resistance to chilling stress remain unclear . Ji et al .…”

“…14,15 There are several reports on the physiological and molecular changes occurring during postharvest sweet potato storage, but the endogenous factors contributing to increased resistance to chilling stress remain unclear. 6,16,17 Ji et al confirmed that phenylalanine metabolism may play a vital role in preventing chilling injury during low-temperature storage. 6 The down-regulation of antioxidant enzyme activities may represent impairment of functional genes with low temperature in sweet potato.…”