Institute of Plant Molecular and Developmental Biology, Heinrich-Heine-University, 40225 Duesseldorf, Germany.
Plant Cell. 2011 Jun;23(6):2087-105. doi: 10.1105/tpc.111.086264. Epub 2011 Jun 24.
Selective pressure exerted by a massive decline in atmospheric CO(2) levels 55 to 40 million years ago promoted the evolution of a novel, highly efficient mode of photosynthetic carbon assimilation known as C(4) photosynthesis. C(4) species have concurrently evolved multiple times in a broad range of plant families, and this multiple and parallel evolution of the complex C(4) trait indicates a common underlying evolutionary mechanism that might be elucidated by comparative analyses of related C(3) and C(4) species. Here, we use mRNA-Seq analysis of five species within the genus Flaveria, ranging from C(3) to C(3)-C(4) intermediate to C(4) species, to quantify the differences in the transcriptomes of closely related plant species with varying degrees of C(4)-associated characteristics. Single gene analysis defines the C(4) cycle enzymes and transporters more precisely and provides new candidates for yet unknown functions as well as identifies C(4) associated pathways. Molecular evidence for a photorespiratory CO(2) pump prior to the establishment of the C(4) cycle-based CO(2) pump is provided. Cluster analysis defines the upper limit of C(4)-related gene expression changes in mature leaves of Flaveria as 3582 alterations.
5500 万至 4000 万年前，大气 CO2 水平的大规模下降所产生的选择压力，促进了一种新型、高效的光合作用碳同化模式的进化，这种模式被称为 C4 光合作用。C4 物种在广泛的植物科中多次同时进化，这种复杂的 C4 性状的多次和并行进化表明，存在一种共同的潜在进化机制，通过对相关的 C3 和 C4 物种进行比较分析，可能会阐明这种机制。在这里，我们使用 mRNA-Seq 分析了假蒴苞属内的五个物种，从 C3 到 C3-C4 中间型到 C4 物种，定量比较了具有不同程度 C4 相关特征的近缘植物物种的转录组差异。单基因分析更精确地定义了 C4 循环酶和转运蛋白，并提供了新的候选基因，用于尚未确定的功能，同时也确定了 C4 相关途径。提供了在建立基于 C4 循环的 CO2 泵之前存在光呼吸 CO2 泵的分子证据。聚类分析确定了假蒴苞属成熟叶片中与 C4 相关的基因表达变化的上限为 3582 个变化。
