Robert W Holley Center for Agriculture and Health, USDA-ARS, Cornell University, Ithaca, NY 14853, USA.
BMC Plant Biol. 2011 Nov 23;11:169. doi: 10.1186/1471-2229-11-169.
Chloroplasts are the green plastids where photosynthesis takes place. The biogenesis of chloroplasts requires the coordinate expression of both nuclear and chloroplast genes and is regulated by developmental and environmental signals. Despite extensive studies of this process, the genetic basis and the regulatory control of chloroplast biogenesis and development remain to be elucidated.
Green cauliflower mutant causes ectopic development of chloroplasts in the curd tissue of the plant, turning the otherwise white curd green. To investigate the transcriptional control of chloroplast development, we compared gene expression between green and white curds using the RNA-seq approach. Deep sequencing produced over 15 million reads with lengths of 86 base pairs from each cDNA library. A total of 7,155 genes were found to exhibit at least 3-fold changes in expression between green and white curds. These included light-regulated genes, genes encoding chloroplast constituents, and genes involved in chlorophyll biosynthesis. Moreover, we discovered that the cauliflower ELONGATED HYPOCOTYL5 (BoHY5) was expressed higher in green curds than white curds and that 2616 HY5-targeted genes, including 1600 up-regulated genes and 1016 down-regulated genes, were differently expressed in green in comparison to white curd tissue. All these 1600 up-regulated genes were HY5-targeted genes in the light.
The genome-wide profiling of gene expression by RNA-seq in green curds led to the identification of large numbers of genes associated with chloroplast development, and suggested the role of regulatory genes in the high hierarchy of light signaling pathways in mediating the ectopic chloroplast development in the green curd cauliflower mutant.
叶绿体是进行光合作用的绿色质体。叶绿体的生物发生需要核基因和叶绿体基因的协调表达，并受发育和环境信号的调节。尽管对这一过程进行了广泛的研究，但叶绿体生物发生和发育的遗传基础和调控控制仍有待阐明。
绿菜花突变体导致植物花椰菜的叶球组织中叶绿体的异位发育，使原本白色的叶球变绿。为了研究叶绿体发育的转录调控，我们使用 RNA-seq 方法比较了绿花椰菜和白花椰菜之间的基因表达。从每个 cDNA 文库中深度测序产生了超过 1500 万个 86 个碱基对长的读段。总共发现 7155 个基因在绿花椰菜和白花椰菜之间的表达至少有 3 倍的变化。这些基因包括光调控基因、编码叶绿体成分的基因和参与叶绿素生物合成的基因。此外，我们发现花椰菜伸长的下胚轴 5（BoHY5）在绿花椰菜中的表达高于白花椰菜，并且 2616 个 HY5 靶向基因，包括 1600 个上调基因和 1016 个下调基因，在绿花椰菜中与白花椰菜组织的表达不同。所有这些 1600 个上调基因都是光下 HY5 靶向基因。
通过 RNA-seq 在绿花椰菜中进行的全基因组基因表达谱分析，鉴定出了大量与叶绿体发育相关的基因，并表明了调控基因在介导绿花椰菜突变体中叶绿体的异位发育的光信号途径中的高级层次结构中的作用。
