Mechanism and Significance of Chlorophyll Breakdown
Mechanism and Significance of Chlorophyll Breakdown
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DOI：
10.1007/s00344-013-9392-y
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发表时间：
2014-03-01
影响因子：
4.8
通讯作者：
Hoertensteiner, Stefan
中科院分区：
文献类型：
--
作者：
Christ, Bastien;Hoertensteiner, Stefan
叶绿素分解是叶片衰老和果实成熟最明显的标志。近年来已经阐明了一个多步骤的途径，可以分为两个主要部分。在第一阶段中，其通常在高等植物中是活跃的，叶绿素通过几种光反应中间体在叶绿体内转化为初级无色分解产物。叶绿素分解的第二部分发生在细胞质和液泡中。在此阶段，主要的无色中间体在很大程度上物种特异性反应中被修饰为许多相似但结构不同的线性四吡咯产物，这些产物最终储存在衰老细胞的液泡中。到目前为止，叶绿素分解第一阶段的大部分生化反应已经阐明，基因已经确定。相比之下，在第二阶段的代谢产物的运输和修改机制在很大程度上是未知的。本文综述了叶绿素分解过程中的生化反应，重点介绍了叶绿素分解过程中的第二阶段反应和叶绿素分解过程中释放的副产物。
Chlorophyll breakdown is the most obvious sign of leaf senescence and fruit ripening. A multistep pathway has been elucidated in recent years that can be divided into two major parts. In the first phase, which commonly is active in higher plants, chlorophyll is converted via several photoreactive intermediates to a primary colorless breakdown product within the chloroplast. The second part of chlorophyll breakdown takes place in the cytosol and the vacuole. During this phase, the primary colorless intermediate is modified in largely species-specific reactions to a number of similar, yet structurally different, linear tetrapyrrolic products that finally are stored within the vacuole of senescing cells. To date, most of the biochemical reactions of the first phase of chlorophyll breakdown have been elucidated and genes have been identified. By contrast, mechanisms of catabolite transport and modification during the second phase are largely unknown. This review summarizes the current knowledge on the biochemical reactions involved in chlorophyll breakdown, with a special focus on the second-phase reactions and the fate of by-products that are released from chlorophyll during its breakdown.