Key Laboratory of Ecological Forestry Engineering of Sichuan Province, College of Forestry, Sichuan Agricultural University, Chengdu, 611130, China.
Guangdong Key Laboratory for Innovative Development and Utilization of Forest Plant Germplasm, State Key Laboratory for Conservation and Utilization of Subtropical Agro-Bioresources, College of Forestry and Landscape Architecture, South China Agricultural University, Guangzhou, 510642, China.
BMC Genomics. 2020 Jan 28;21(1):81. doi: 10.1186/s12864-020-6521-4.
Zanthoxylum armatum (Z. armatum) is a highly economically important tree that presents a special numbing taste. However, the underlying regulatory mechanism of the numbing taste remains poorly understood. Thus, the elucidation of the key genes associated with numbing taste biosynthesis pathways is critical for providing genetic information on Z. armatumand the breeding of high-quality germplasms of this species.
Here, de novo transcriptome assembly was performed for the five major organs of Z. armatum, including the roots, stems, leaf buds, mature leaves and fruits. A total of 111,318 unigenes were generated with an average length of 1014 bp. Additionally, a large number of SSRs were obtained to improve our understanding of the phylogeny and genetics of Z. armatum. The organ-specific unigenes of the five major samples were screened and annotated via GO and KEGG enrichment analysis. A total of 53 and 34 unigenes that were exclusively upregulated in fruit samples were identified as candidate unigenes for terpenoid biosynthesis or fatty acid biosynthesis, elongation and degradation pathways, respectively. Moreover, 40 days after fertilization (Fr4 stage) could be an important period for the accumulation of terpenoid compounds during the fruit development and maturation of Z. armatum. The Fr4 stage could be a key point at which the first few steps of the fatty acid biosynthesis process are promoted, and the catalysis of subsequent reactions could be significantly induced at 62 days after fertilization (Fr6 stage).
The present study realized de novo transcriptome assembly for the five major organs of Z. armatum. To the best of our knowledge, this study provides the first comprehensive analysis revealing the genes underlying the special numbing taste of Z. armatum. The assembled transcriptome profiles expand the available genetic information on this species and will contribute to gene functional studies, which will aid in the engineering of high-quality cultivars of Z. armatum.
花椒（Zanthoxylum armatum）是一种极具经济价值的树种，具有特殊的麻味。然而，其麻味的潜在调控机制仍知之甚少。因此，阐明与麻味生物合成途径相关的关键基因对于提供花椒的遗传信息和培育该物种的优质种质资源至关重要。
本研究对花椒的五个主要器官（根、茎、叶芽、成熟叶和果实）进行了从头转录组组装。共生成了 111318 条 unigenes，平均长度为 1014bp。此外，还获得了大量的 SSR，以提高我们对花椒系统发育和遗传学的理解。对五个主要样本的器官特异性 unigenes进行了 GO 和 KEGG 富集分析。共鉴定出 53 个和 34 个在果实样本中特异性上调的 unigenes，分别作为萜类生物合成或脂肪酸生物合成、延伸和降解途径的候选 unigenes。此外，受精后 40 天（Fr4 期）可能是花椒果实发育和成熟过程中萜类化合物积累的重要时期。Fr4 期可能是促进脂肪酸生物合成过程早期几步的关键点，随后的反应催化在受精后 62 天（Fr6 期）可显著诱导。
本研究实现了花椒五个主要器官的从头转录组组装。据我们所知，本研究首次全面分析了花椒特殊麻味的基因基础。组装的转录组图谱扩展了该物种的可用遗传信息，并将有助于基因功能研究，这将有助于花椒优质品种的培育。
