A qualitative analysis of the regulation of cyclic electron flow around photosystem I from the post-illumination chlorophyll fluorescence transient in Arabidopsis: a new platform for the in vivo investigation of the chloroplast redox state
A qualitative analysis of the regulation of cyclic electron flow around photosystem I from the post-illumination chlorophyll fluorescence transient in Arabidopsis: a new platform for the in vivo investigation of the chloroplast redox state
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DOI：
10.1007/s11120-009-9525-0
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发表时间：
2010-02-01
影响因子：
3.7
通讯作者：
Tsuyama, Michito
中科院分区：
文献类型：
--
作者：
Gotoh, Eiji;Matsumoto, Masayoshi;Tsuyama, Michito
研究了拟南芥在停止光化光照后叶绿素荧光的瞬变现象，这种现象归因于基质还原剂通过NAD(P)H脱氢酶(NDH)复合体给电子给与质醌(PQ)。在一个缺乏NDH复合体(NdhM)的突变体中，空气中没有这种瞬变。然而，在ndhm中，在含有2%O-2的无二氧化碳空气中检测到了瞬变。为了研究原因，ndhM与pgr5突变体杂交，该突变体在依赖铁氧还蛋白(FD)的电子供体从NADPH到PQ的过程中受到损害，已知在光系统I(PSI)周围的循环电子流动中依赖于NDH的PQ减少是多余的。在ndhM pgr5中，即使在无CO2和2%O-2的空气中也不存在瞬变现象，这表明依赖于FD(或PGR5)的PQ降低也可以诱导光照后的瞬变过程。另一方面，在叶绿体果糖-1，6-二磷酸缩醛酶(FBA)活性受损的突变体中，在正常空气中，叶绿素荧光的瞬时增加被增强。这个突变体被称为fba3-1，它提供了独特的机会来研究两条路径，即依赖NDH和Fd(或PGR5)的路径对PSI循环电子流的相对贡献。将fba3-1与ndhm或pgr5杂交并评估瞬变表明，PSI循环电子流的主要路径从依赖于NDH的路径转变为依赖于FD的路径，以响应线性电子流的汇限制。
A transient in chlorophyll fluorescence after cessation of actinic light illumination, which has been ascribed to electron donation from stromal reductants to plastoquinone (PQ) by the NAD(P)H-dehydrogenase (NDH) complex, was investigated in Arabidopsis thaliana. The transient was absent in air in a mutant lacking the NDH complex (ndhM). However, in ndhM, the transient was detected in CO2-free air containing 2% O-2. To investigate the reason, ndhM was crossed with a pgr5 mutant impaired in ferredoxin (Fd)-dependent electron donation from NADPH to PQ, which is known to be redundant for NDH-dependent PQ reduction in the cyclic electron flow around photosystem I (PSI). In ndhM pgr5, the transient was absent even in CO2-free air with 2% O-2, demonstrating that the post-illumination transient can also be induced by the Fd- (or PGR5)-dependent PQ reduction. On the other hand, the transient increase in chlorophyll fluorescence was found to be enhanced in normal air in a mutant impaired in plastid fructose-1,6-bisphosphate aldolase (FBA) activity. The mutant, termed fba3-1, offers unique opportunities to examine the relative contribution of the two paths, i.e., the NDH- and Fd- (or PGR5)-dependent paths, on the PSI cyclic electron flow. Crossing fba3-1 with either ndhM or pgr5 and assessing the transient suggested that the main route for the PSI cyclic electron flow shifts from the NDH-dependent path to the Fd-dependent path in response to sink limitation of linear electron flow.