Dissection of dynamic transcriptome landscape of leaf, bract, and lupulin gland in hop (Humulus lupulus L.)

Kumar Mishra, Ajay (author), Kocábek, Tomáš (author), Nath, Vishnu Sukumari (author), Awasthi, Praveen (author), Shrestha, Ankita (author), Kumar Killi, Uday (author), Jakše, Jernej (author), Patzak, Josef (author), Krofta, Karel (author), Matoušek, Jaroslav (author)

The hop plant (Humulus lupulus L.) produces several valuable secondary metabolites, such as prenylflavonoid, bitter acids, and essential oils. These compounds are biosynthesized in glandular trichomes (lupulin glands) endowed with pharmacological properties and widely implicated in the beer brewing industry. The present study is an attempt to generate exhaustive information of transcriptome dynamics and gene regulatory mechanisms involved in biosynthesis and regulation of these compounds, developmental changes including trichome development at three development stages, namely leaf, bract, and mature lupulin glands. Using high-throughput RNA-Seq technology, a total of 61.13, 50.01, and 20.18 Mb clean reads in the leaf, bract, and lupulin gland libraries, respectively, were obtained and assembled into 43,550 unigenes. The putative functions were assigned to 30,996 transcripts (71.17%) based on basic local alignment search tool similarity searches against public sequence databases, including GO, KEGG, NR, and COG families, which indicated that genes are principally involved in fundamental cellular and molecular functions, and biosynthesis of secondary metabolites. The expression levels of all unigenes were analyzed in leaf, bract, and lupulin glands tissues of hop. The expression profile of transcript encoding enzymes of BCAA metabolism, MEP, and shikimate pathway was most up-regulated in lupulin glands compared with leaves and bracts. Similarly, the expression levels of the transcription factors and structural genes that directly encode enzymes involved in xanthohumol, bitter acids, and terpenoids biosynthesis pathway were found to be significantly enhanced in lupulin glands, suggesting that production of these metabolites increases after the leaf development. In addition, numerous genes involved in primary metabolism, lipid metabolism, photosynthesis, generation of precursor metabolites/energy, protein modification, transporter activity, and cell wall component biogenesis were differentially regulated in three developmental stages, suggesting their involvement in the dynamics of the lupulin gland development. The identification of differentially regulated trichome-related genes provided a new foundation for molecular research on trichome development and differentiation in hop. In conclusion, the reported results provide directions for future functional genomics studies for genetic engineering or molecular breeding for augmentation of secondary metabolite content in hop.

• Language: English
• Keywords: bitter acids, prenylflavonoids, terpenoids, trichome, Humulus lupulus, lupulin glands, RNA sequencing
• Work type: Article
• Typology: 1.01 - Original Scientific Article
• Organization: BF - Biotechnical Faculty
• Publication status: Published
• Publication version: Version of Record
• Year: 2020
• Number of pages: 24 str.
• Numbering: Vol. 21, iss. 1, art. 233
• PID: 20.500.12556/RUL-133282
• UDC: 577.2
• ISSN on article: 1422-0067
• DOI: 10.3390/ijms21010233
• COBISS.SI-ID: 9402745
• Publication date in RUL: 19.11.2021

Record is a part of a journal

• Title: International journal of molecular sciences
• Shortened title: Int. j. mol. sci.
• Publisher: MDPI
• ISSN: 1422-0067
• COBISS.SI-ID: 2779162

Licences

• License: CC BY 4.0, Creative Commons Attribution 4.0 International
• Link: http://creativecommons.org/licenses/by/4.0/
• Description: This is the standard Creative Commons license that gives others maximum freedom to do what they want with the work as long as they credit the author.
• Licensing start date: 01.01.2020

Secondary language

• Language: Slovenian
• Keywords: hmelj, genetika, RNA sekvenciranje, sekundarni metaboliti, molekularna biologija

Projects

• Funder: Other - Other funder or multiple funders
• Funding programme: Czech Science Foundation GACR
• Project number: 19-19629S

• Funder: Other - Other funder or multiple funders
• Funding programme: Operational Programme Research, Development and Education
• Project number: CZ.02.2.69/0.0/0.0/16_027/0008357
• Acronym: MEMOBIC