Cytokinin-Dependent Photorespiration and the Protection of Photosynthesis during Water Deficit
Cytokinin-Dependent Photorespiration and the Protection of Photosynthesis during Water Deficit
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DOI：
10.1104/pp.109.139378
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发表时间：
2009-07-01
期刊：
影响因子：
7.4
通讯作者：
Blumwald, Eduardo
中科院分区：
文献类型：
--
作者：
Rivero, Rosa M.;Shulaev, Vladimir;Blumwald, Eduardo
我们研究了P-SARK：：IPT（衰老相关受体激酶：：异戊烯基转移酶）的表达和细胞分裂素的产生对转基因烟草（烟草品种SR 1）植物光合作用的几个方面的影响，生长在最佳或限制（30%的最佳）浇水制度。野生型和转基因P-SARK-IPT植物在最佳或限制浇水条件下生长的叶片气孔导度无显著差异。另一方面，有一个显着减少的最大速率的电子传递，以及使用丙糖磷酸盐仅在野生型植物在生长过程中限制浇水，表明在生长过程中的光合作用的生化控制水分亏缺。在水分亏缺条件下，转基因植物表现出增加过氧化氢酶内过氧化物酶，保持叶绿体，过氧化物酶体和线粒体之间的物理关联，并增加CO2补偿点，表明细胞分裂素介导的发生在转基因植物的光呼吸。光呼吸对转基因植物对水分亏缺的耐受性的贡献也得到了编码参与乙醇酸转化为核酮糖-1，5-二磷酸的酶的转录本的增加的支持。此外，转录本的增加表明细胞分裂素诱导的光呼吸升高，这表明光呼吸在保护光合作用过程中的贡献及其在水分胁迫期间的有益作用。
We investigated the effects of P-SARK::IPT (for Senescence-Associated Receptor Kinase::Isopentenyltransferase) expression and cytokinin production on several aspects of photosynthesis in transgenic tobacco (Nicotiana tabacum cv SR1) plants grown under optimal or restricted (30% of optimal) watering regimes. There were no significant differences in stomatal conductance between leaves from wild-type and transgenic P-SARK-IPT plants grown under optimal or restricted watering. On the other hand, there was a significant reduction in the maximum rate of electron transport as well as the use of triose-phosphates only in wild-type plants during growth under restricted watering, indicating a biochemical control of photosynthesis during growth under water deficit. During water deficit conditions, the transgenic plants displayed an increase in catalase inside peroxisomes, maintained a physical association among chloroplasts, peroxisomes, and mitochondria, and increased the CO2 compensation point, indicating the cytokinin-mediated occurrence of photorespiration in the transgenic plants. The contribution of photorespiration to the tolerance of transgenic plants to water deficit was also supported by the increase in transcripts coding for enzymes involved in the conversion of glycolate to ribulose-1,5-bisphosphate. Moreover, the increase in transcripts indicated a cytokinin-induced elevation in photorespiration, suggesting the contribution of photorespiration in the protection of photosynthetic processes and its beneficial role during water stress.