Rademacher Nadine, Wrobel Thomas J, Rossoni Alessandro W, Kurz Samantha, Bräutigam Andrea, Weber Andreas P M, Eisenhut Marion
Institute of Plant Biochemistry, Cluster of Excellence on Plant Sciences (CEPLAS), Heinrich Heine University, Universitätsstraße 1, 40225 Düsseldorf, Germany.
Leibniz-Institut für Pflanzengenetik und Kulturpflanzenforschung (IPK), Corrensstraße 3, 06466 Stadt Seeland, OT Gatersleben, Germany.
J Plant Physiol. 2017 Oct;217:49-56. doi: 10.1016/j.jplph.2017.06.014. Epub 2017 Jul 4.
Cyanidioschyzon merolae (C. merolae) is an acidophilic red alga growing in a naturally low carbon dioxide (CO) environment. Although it uses a ribulose 1,5-bisphosphate carboxylase/oxygenase with high affinity for CO, the survival of C. merolae relies on functional photorespiratory metabolism. In this study, we quantified the transcriptomic response of C. merolae to changes in CO conditions. We found distinct changes upon shifts between CO conditions, such as a concerted up-regulation of photorespiratory genes and responses to carbon starvation. We used the transcriptome data set to explore a hypothetical CO concentrating mechanism in C. merolae, based on the assumption that photorespiratory genes and possible candidate genes involved in a CO concentrating mechanism are co-expressed. A putative bicarbonate transport protein and two α-carbonic anhydrases were identified, which showed enhanced transcript levels under reduced CO conditions. Genes encoding enzymes of a PEPCK-type C pathway were co-regulated with the photorespiratory gene cluster. We propose a model of a hypothetical low CO compensation mechanism in C. merolae integrating these low CO-inducible components.
梅氏蓝纤维藻（C. merolae）是一种嗜酸红藻，生长在自然低二氧化碳（CO）环境中。尽管它使用对CO具有高亲和力的1,5-二磷酸核酮糖羧化酶/加氧酶，但梅氏蓝纤维藻的存活依赖于功能性光呼吸代谢。在本研究中，我们量化了梅氏蓝纤维藻对CO条件变化的转录组反应。我们发现在CO条件转变时存在明显变化，例如光呼吸基因的协同上调以及对碳饥饿的反应。基于光呼吸基因与参与CO浓缩机制的可能候选基因共表达的假设，我们利用转录组数据集探索梅氏蓝纤维藻中一种假设的CO浓缩机制。鉴定出一种假定的碳酸氢盐转运蛋白和两种α-碳酸酐酶，它们在CO浓度降低的条件下转录水平升高。编码PEPCK型C途径酶的基因与光呼吸基因簇共同调控。我们提出了一个整合这些低CO诱导成分的梅氏蓝纤维藻假设低CO补偿机制模型。
