Division of Applied Life Science (BK21-WCU Program), Plant Molecular Biology and Biotechnology Research Center, Gyeongsang National University, Jinju, 660-701, Korea.
Plant Mol Biol. 2012 Jul;79(4-5):413-27. doi: 10.1007/s11103-012-9919-9. Epub 2012 May 12.
The ripe fruit of Momordica cochinchinensis Spreng, known as gac, is featured by very high carotenoid content. Although this plant might be a good resource for carotenoid metabolic engineering, so far, the genes involved in the carotenoid metabolic pathways in gac were unidentified due to lack of genomic information in the public database. In order to expedite the process of gene discovery, we have undertaken Illumina deep sequencing of mRNA prepared from aril of gac fruit. From 51,446,670 high-quality reads, we obtained 81,404 assembled unigenes with average length of 388 base pairs. At the protein level, gac aril transcripts showed about 81.5% similarity with cucumber proteomes. In addition 17,104 unigenes have been assigned to specific metabolic pathways in Kyoto Encyclopedia of Genes and Genomes, and all of known enzymes involved in terpenoid backbones biosynthetic and carotenoid biosynthetic pathways were also identified in our library. To analyze the relationship between putative carotenoid biosynthesis genes and alteration of carotenoid content during fruit ripening, digital gene expression analysis was performed on three different ripening stages of aril. This study has revealed putative phytoene synthase, 15-cis-phytone desaturase, zeta-carotene desaturase, carotenoid isomerase and lycopene epsilon cyclase might be key factors for controlling carotenoid contents during aril ripening. Taken together, this study has also made availability of a large gene database. This unique information for gac gene discovery would be helpful to facilitate functional studies for improving carotenoid quantities.
人心果是一种盛产于成熟果实的植物，其学名为“Momordica cochinchinensis Spreng”，俗称“gac”，该果实的特点是类胡萝卜素含量非常高。尽管这种植物可能是类胡萝卜素代谢工程的良好资源，但由于公共数据库中缺乏基因组信息，到目前为止，gac 中参与类胡萝卜素代谢途径的基因仍未被鉴定。为了加快基因发现的进程，我们对人心果种仁的 mRNA 进行了 Illumina 深度测序。从 51446670 条高质量的reads 中，我们获得了 81404 条组装的 unigenes，平均长度为 388 个碱基。在蛋白质水平上，人心果种仁转录本与黄瓜蛋白质组的相似度约为 81.5%。此外，17104 条 unigenes被分配到京都基因与基因组百科全书的特定代谢途径中，并且我们的文库中还鉴定了所有已知的萜类骨架生物合成和类胡萝卜素生物合成途径中涉及的酶。为了分析假定的类胡萝卜素生物合成基因与果实成熟过程中类胡萝卜素含量变化之间的关系，我们对种仁的三个不同成熟阶段进行了数字基因表达分析。这项研究揭示了假定的八氢番茄红素合酶、15-顺式-phytonedesaturase、ζ-胡萝卜素脱饱和酶、类胡萝卜素异构酶和番茄红素ε环化酶可能是控制种仁成熟过程中类胡萝卜素含量的关键因素。综上所述，本研究还提供了一个大型基因数据库。这些人心果基因发现的独特信息将有助于促进提高类胡萝卜素含量的功能研究。
