[5-1130-P] Postharvest/Food Technology and Process Engineering (5th)

[5-1130-P-13] RNA-Seq analysis of the transcriptome and genes expression profile during the browning of Lotus Root (Nelumbo nucifera)

*Kanjana Worarad¹, Haruka Norii¹, Yuya Muchizuki¹, Takashi Ishii², Keiko Shinohara³, Takao Miyamoto ⁴, Eiichi Inoue ¹ (1. Ibaraki University(Japan), 2. Ibaraki Agricultural Center, Horticultural Research Institute (Japan), 3. Tokushima Agriculture, Forestry and Fisheries Technology Support Center(Japan), 4. Renkon3kyodai Co.Ltd(Japan))

Keywords:Browning disorder, Metabolic pathways, RNA sequencing, Transcriptomics, Postharvest physiology

Lotus root (Nelumbo nucifera) has been widely cultivated in Japan. There is crisp texture, white color and enriched with a source of nutritional components. The consumption/production of fresh-cut lotus root has continuously increased as more consumers demand convenient and ready-to-eat foods. However, it is well known that the processing, storage and transportation of fresh-cut fruits and vegetables promotes a faster physiological deterioration, mainly browning and reduces the value of a product. This study aimed to clarify the functions of unigenes and browning associated metabolic pathway of intact lotus root during long-term storage using RNA-sequencing techniques. Lotus peel from the main cultivar in Ibaraki prefecture ‘Kanasumi No.34’ after harvest (AH), and unpacked (UP), and packed with water (PW) after storage under 5 °C for 6 hr. were collected. Over 200 million short single-end reads were mapped onto the Nelumbo nucifera consensus coding sequence set, and differences in the expression profiles between AH, UP, and PW tissues were assessed to identify candidate genes associated with internal browning in a tissue-specific manner. Based on Swiss-Prot, TrEMBL, KEGG mapping pathway and GO ontology databases, genes involved in phenylpropanoid biosynthesis, tyrosine metabolism, and lipid metabolism were significantly upregulated in the UP and PW when compared with AH. The expression levels of several of them will be confirmed using qRT-PCR. Additionally, the gene expression data presented in this study will help elucidate the molecular mechanism of browning development in lotus root at long-term storage. Base on this study, including phenylpropanoid biosynthesis-related genes, lipid-related genes (related to membrane alterations, and fatty acid degradation), for browning development in lotus root is proposed, which may be relevant for future studies towards improving the postharvest life of lotus root.