National Key Laboratory of Crop Genetic Improvement, Huazhong Agricultural University, Wuhan, Hubei, PR China.
BMC Genomics. 2009 Nov 18;10:540. doi: 10.1186/1471-2164-10-540.
Interest in lycopene metabolism and regulation is growing rapidly because accumulative studies have suggested an important role for lycopene in human health promotion. However, little is known about the molecular processes regulating lycopene accumulation in fruits other than tomato so far.
On a spontaneous sweet orange bud mutant with abnormal lycopene accumulation in fruits and its wild type, comparative transcripts profiling was performed using Massively Parallel Signature Sequencing (MPSS). A total of 6,877,027 and 6,275,309 reliable signatures were obtained for the wild type (WT) and the mutant (MT), respectively. Interpretation of the MPSS signatures revealed that the total number of transcribed gene in MT is 18,106, larger than that in WT 17,670, suggesting that newly initiated transcription occurs in the MT. Further comparison of the transcripts abundance between MT and WT revealed that 3,738 genes show more than two fold expression difference, and 582 genes are up- or down-regulated at 0.05% significance level by more than three fold difference. Functional assignments of the differentially expressed genes indicated that 26 reliable metabolic pathways are altered in the mutant; the most noticeable ones are carotenoid biosynthesis, photosynthesis, and citrate cycle. These data suggest that enhanced photosynthesis and partial impairment of lycopene downstream flux are critical for the formation of lycopene accumulation trait in the mutant.
This study provided a global picture of the gene expression changes in a sweet orange red-flesh mutant as compared to the wild type. Interpretation of the differentially expressed genes revealed new insight into the molecular processes regulating lycopene accumulation in the sweet orange red-flesh mutant.
由于累积的研究表明番茄红素在促进人类健康方面起着重要作用，因此人们对番茄红素代谢和调节的兴趣迅速增长。然而，到目前为止，人们对除番茄以外的水果中调节番茄红素积累的分子过程知之甚少。
在一个自发的甜橙芽突变体中，果实中番茄红素异常积累，对其野生型进行了大规模平行签名测序（MPSS）的比较转录谱分析。野生型（WT）和突变体（MT）分别获得了 6877027 和 6275309 个可靠的签名。对 MPSS 签名的解释表明，MT 中转录基因的总数为 18106，大于 WT 的 17670，表明在 MT 中发生了新的起始转录。进一步比较 MT 和 WT 之间的转录丰度，发现 3738 个基因的表达差异超过两倍，582 个基因的表达水平差异超过 0.05%的显著性水平上调或下调超过三倍。差异表达基因的功能分配表明，26 个可靠的代谢途径在突变体中发生了改变；最明显的是类胡萝卜素生物合成、光合作用和柠檬酸循环。这些数据表明，增强的光合作用和番茄红素下游通量的部分损伤对于突变体中番茄红素积累性状的形成是至关重要的。
本研究提供了一个与野生型相比甜橙红肉突变体基因表达变化的整体情况。对差异表达基因的解释揭示了调节甜橙红肉突变体中番茄红素积累的分子过程的新见解。
