Department of Botany and Laboratories of Analytical Biology, National Museum of Natural History, Smithsonian Institution, PO Box 37012, Washington, DC, 20013-7012, USA.
Thomas Jefferson High School for Science and Technology, 6560 Braddock Rd, Alexandria, VA, 22312, USA.
Sci Rep. 2019 Mar 12;9(1):4230. doi: 10.1038/s41598-019-40227-z.
The curry tree (Bergera koenigii L.) is a widely cultivated plant used in South Asian cooking. Next-generation sequencing was used to generate the transcriptome of the curry leaf to detect changes in gene expression during leaf development, such as those genes involved in the production of oils which lend the leaf its characteristic taste, aroma, and medicinal properties. Using abundance estimation (RSEM) and differential expression analysis, genes that were significantly differentially expressed were identified. The transcriptome was annotated with BLASTx using the non-redundant (nr) protein database, and Gene Ontology (GO) terms were assigned based on the top BLAST hit using Blast2GO. Lastly, functional enrichment of the assigned GO terms was analyzed for genes that were significantly differentially expressed. Of the most enriched GO categories, pathways involved in cell wall, membrane, and lignin synthesis were found to be most upregulated in immature leaf tissue, possibly due to the growth and expansion of the leaf tissue. Terpene synthases, which synthesize monoterpenes and sesquiterpenes, which comprise much of the curry essential oil, were found to be significantly upregulated in mature leaf tissue, suggesting that oil production increases later in leaf development. Enzymes involved in pigment production were also significantly upregulated in mature leaves. The findings were based on computational estimates of gene expression from RNA-seq data, and further study is warranted to validate these results using targeted techniques, such as quantitative PCR.
咖喱树（Bergera koenigii L.）是一种广泛种植的植物，用于南亚烹饪。下一代测序被用于生成咖喱叶的转录组，以检测叶片发育过程中基因表达的变化，例如涉及产生使叶片具有其特征性味道、香气和药用特性的油的基因。使用丰度估计（RSEM）和差异表达分析，鉴定了差异表达显著的基因。使用非冗余（nr）蛋白质数据库对转录组进行 BLASTx 注释，并使用 Blast2GO 根据顶级 BLAST 命中分配基因本体论（GO）术语。最后，对差异表达显著的基因进行了GO 术语分配的功能富集分析。在最丰富的 GO 类别中，发现与细胞壁、膜和木质素合成有关的途径在未成熟叶片组织中上调最显著，这可能是由于叶片组织的生长和扩张所致。合成单萜和倍半萜的萜烯合酶在成熟叶片组织中上调显著，表明油的产生在叶片发育后期增加。参与色素生成的酶在成熟叶片中也被显著上调。这些发现基于 RNA-seq 数据的基因表达计算估计，需要进一步的研究来使用靶向技术（如定量 PCR）验证这些结果。
