College of Agronomy, Northwest A&F University, Yangling 712100, China.
College of Food Science and Engineering, Northwest A&F University, Yangling 712100, China.
Int J Mol Sci. 2018 May 29;19(6):1594. doi: 10.3390/ijms19061594.
The photosynthetic capacity and efficiency of a crop depends on the biosynthesis of photosynthetic pigments and chloroplast development. However, little is known about the molecular mechanisms of chloroplast development and chlorophyll (Chl) biosynthesis in common wheat because of its huge and complex genome. , a spontaneous yellow-green leaf color mutant of winter wheat, exhibits reduced Chl contents and abnormal chloroplast development. Thus, we searched for candidate genes associated with this phenotype. Comparative transcriptome profiling was performed using leaves from the yellow leaf color type (Y) and normal green color type (G) of the mutant progeny. We identified 1227 differentially expressed genes (DEGs) in Y compared with G (i.e., 689 upregulated genes and 538 downregulated genes). Gene ontology and pathway enrichment analyses indicated that the DEGs were involved in Chl biosynthesis (i.e., magnesium chelatase subunit H (CHLH) and protochlorophyllide oxidoreductase (POR) genes), carotenoid biosynthesis (i.e., β-carotene hydroxylase (BCH) genes), photosynthesis, and carbon fixation in photosynthetic organisms. We also identified heat shock protein (HSP) genes (, , , and ) and heat shock transcription factor genes that might have vital roles in chloroplast development. Quantitative RT-PCR analysis of the relevant DEGs confirmed the RNA-Seq results. Moreover, measurements of seven intermediate products involved in Chl biosynthesis and five carotenoid compounds involved in carotenoid-xanthophyll biosynthesis confirmed that CHLH and BCH are vital enzymes for the unusual leaf color phenotype in Y type. These results provide insights into leaf color variation in wheat at the transcriptional level.
作物的光合能力和效率取决于光合色素的生物合成和叶绿体的发育。然而，由于普通小麦基因组庞大且复杂，其叶绿体发育和叶绿素（Chl）生物合成的分子机制知之甚少。, 是冬小麦的自发黄绿叶突变体，表现出 Chl 含量降低和叶绿体发育异常。因此，我们寻找与该表型相关的候选基因。使用突变体后代的黄绿叶色类型（Y）和正常绿叶色类型（G）的叶片进行比较转录组谱分析。我们在 Y 中鉴定了 1227 个与 G 相比差异表达的基因（即 689 个上调基因和 538 个下调基因）。基因本体论和途径富集分析表明，差异表达基因参与 Chl 生物合成（即镁螯合酶亚基 H（CHLH）和原叶绿素氧化还原酶（POR）基因）、类胡萝卜素生物合成（即β-胡萝卜素羟化酶（BCH）基因）、光合作用和光合生物中的碳固定。我们还鉴定了热休克蛋白（HSP）基因（,,, 和 ）和热休克转录因子基因，它们可能在叶绿体发育中具有重要作用。相关差异表达基因的定量 RT-PCR 分析证实了 RNA-Seq 的结果。此外，Chl 生物合成的七个中间产物和类胡萝卜素-xanthophyll 生物合成的五个类胡萝卜素化合物的测量结果证实，CHLH 和 BCH 是 Y 型异常叶色表型的重要酶。这些结果为小麦在转录水平上的叶片颜色变化提供了新的见解。
