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Transcriptomic and microstructural analyses in Liriodendron tulipifera Linn. reveal candidate genes involved in nectary development and nectar secretion

BACKGROUND: Nectar is a major floral attractant and reward for insects that ensures pollination. Liriodendron, a genus of the Magnoliaceae family, includes only two relict species, L. chinense and L. tulipifera, which are considered “basal angiosperms” according to plant evolutionary history. The fl...

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Autores principales: Liu, Huanhuan, Ma, Jikai, Li, Huogen
Formato: Online Artículo Texto
Lenguaje:English
Publicado: BioMed Central 2019
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6889543/
https://www.ncbi.nlm.nih.gov/pubmed/31791230
http://dx.doi.org/10.1186/s12870-019-2140-0
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author Liu, Huanhuan
Ma, Jikai
Li, Huogen
author_facet Liu, Huanhuan
Ma, Jikai
Li, Huogen
author_sort Liu, Huanhuan
collection PubMed
description BACKGROUND: Nectar is a major floral attractant and reward for insects that ensures pollination. Liriodendron, a genus of the Magnoliaceae family, includes only two relict species, L. chinense and L. tulipifera, which are considered “basal angiosperms” according to plant evolutionary history. The flowers of Liriodendron plants are insect pollinated and secrete nectar to attract pollinators. To date, the morphology and anatomy of nectaries, the mechanism of nectar secretion and the molecular mechanism of nectary development in Liriodendron remain poorly understood. METHODS: In this study, we examined the nectary surface cells and change in starch in L. tulipifera by using scanning electron microscopy and periodic acid-Schiff techniques to select appropriate samples for subsequent research. Transcriptome sequencing was of the top and middle parts of immature nectaries and the middle part of mature and postsecretory nectaries in L. tulipifera was performed. We evaluated the expression profiles of 21 DEGs that are closely related to nectary development and nectar secretion for real-time quantitative PCR analysis. RESULTS: L. tulipifera nectaries are starch-storing nectaries and are located in the top and middle parts of L. tulipifera petals. After analyzing the RNA-seq data, we obtained 115.26 Gb of clean data in 12 libraries and mapped the results to the L. chinense reference genome with 71.02–79.77% efficiency. In total, 26,955 DEGs were identified by performing six pairwise comparisons. The flavonoid biosynthesis, phenylpropanoid biosynthesis, anthocyanin biosynthesis and starch and sucrose metabolism pathways were enriched and related to nectar secretion and pigment change. We identified 56 transcription factor families, and members of the TCP, Trihelix, C2H2, ERF, and MADS families changed dynamically during nectary development. Moreover, to further verify the accuracy of the RNA-seq results, we validated the expression profiles of 21 candidate genes. CONCLUSIONS: We evaluated the nectary development and secretion processes comprehensively and identified many related candidate genes in L. tulipifera. These findings suggest that nectaries play important roles in flavonoid synthesis and petal color presentation.
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spelling pubmed-68895432019-12-11 Transcriptomic and microstructural analyses in Liriodendron tulipifera Linn. reveal candidate genes involved in nectary development and nectar secretion Liu, Huanhuan Ma, Jikai Li, Huogen BMC Plant Biol Research Article BACKGROUND: Nectar is a major floral attractant and reward for insects that ensures pollination. Liriodendron, a genus of the Magnoliaceae family, includes only two relict species, L. chinense and L. tulipifera, which are considered “basal angiosperms” according to plant evolutionary history. The flowers of Liriodendron plants are insect pollinated and secrete nectar to attract pollinators. To date, the morphology and anatomy of nectaries, the mechanism of nectar secretion and the molecular mechanism of nectary development in Liriodendron remain poorly understood. METHODS: In this study, we examined the nectary surface cells and change in starch in L. tulipifera by using scanning electron microscopy and periodic acid-Schiff techniques to select appropriate samples for subsequent research. Transcriptome sequencing was of the top and middle parts of immature nectaries and the middle part of mature and postsecretory nectaries in L. tulipifera was performed. We evaluated the expression profiles of 21 DEGs that are closely related to nectary development and nectar secretion for real-time quantitative PCR analysis. RESULTS: L. tulipifera nectaries are starch-storing nectaries and are located in the top and middle parts of L. tulipifera petals. After analyzing the RNA-seq data, we obtained 115.26 Gb of clean data in 12 libraries and mapped the results to the L. chinense reference genome with 71.02–79.77% efficiency. In total, 26,955 DEGs were identified by performing six pairwise comparisons. The flavonoid biosynthesis, phenylpropanoid biosynthesis, anthocyanin biosynthesis and starch and sucrose metabolism pathways were enriched and related to nectar secretion and pigment change. We identified 56 transcription factor families, and members of the TCP, Trihelix, C2H2, ERF, and MADS families changed dynamically during nectary development. Moreover, to further verify the accuracy of the RNA-seq results, we validated the expression profiles of 21 candidate genes. CONCLUSIONS: We evaluated the nectary development and secretion processes comprehensively and identified many related candidate genes in L. tulipifera. These findings suggest that nectaries play important roles in flavonoid synthesis and petal color presentation. BioMed Central 2019-12-02 /pmc/articles/PMC6889543/ /pubmed/31791230 http://dx.doi.org/10.1186/s12870-019-2140-0 Text en © The Author(s). 2019 Open AccessThis article is distributed under the terms of the Creative Commons Attribution 4.0 International License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and reproduction in any medium, provided you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made. The Creative Commons Public Domain Dedication waiver (http://creativecommons.org/publicdomain/zero/1.0/) applies to the data made available in this article, unless otherwise stated.
spellingShingle Research Article
Liu, Huanhuan
Ma, Jikai
Li, Huogen
Transcriptomic and microstructural analyses in Liriodendron tulipifera Linn. reveal candidate genes involved in nectary development and nectar secretion
title Transcriptomic and microstructural analyses in Liriodendron tulipifera Linn. reveal candidate genes involved in nectary development and nectar secretion
title_full Transcriptomic and microstructural analyses in Liriodendron tulipifera Linn. reveal candidate genes involved in nectary development and nectar secretion
title_fullStr Transcriptomic and microstructural analyses in Liriodendron tulipifera Linn. reveal candidate genes involved in nectary development and nectar secretion
title_full_unstemmed Transcriptomic and microstructural analyses in Liriodendron tulipifera Linn. reveal candidate genes involved in nectary development and nectar secretion
title_short Transcriptomic and microstructural analyses in Liriodendron tulipifera Linn. reveal candidate genes involved in nectary development and nectar secretion
title_sort transcriptomic and microstructural analyses in liriodendron tulipifera linn. reveal candidate genes involved in nectary development and nectar secretion
topic Research Article
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6889543/
https://www.ncbi.nlm.nih.gov/pubmed/31791230
http://dx.doi.org/10.1186/s12870-019-2140-0
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AT majikai transcriptomicandmicrostructuralanalysesinliriodendrontulipiferalinnrevealcandidategenesinvolvedinnectarydevelopmentandnectarsecretion
AT lihuogen transcriptomicandmicrostructuralanalysesinliriodendrontulipiferalinnrevealcandidategenesinvolvedinnectarydevelopmentandnectarsecretion