Assimilatory sulfate reduction in C3, C3-C4, and C4 species of Flaveria
Assimilatory sulfate reduction in C3, C3-C4, and C4 species of Flaveria
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DOI：
10.1104/pp.127.2.543
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发表时间：
2001-10-01
期刊：
影响因子：
7.4
通讯作者：
Kopriva, S
中科院分区：
文献类型：
--
作者：
Koprivova, A;Melzer, M;Kopriva, S
催化硫酸盐同化的前两个步骤的酶，ATP硫酸化酶和腺苷5 '-磷酸硫酸还原酶（APR）的活性仅限于几种C-4单子叶植物的维管束鞘细胞。为了分析这种分布的分子基础，并确定它是否是一个先决条件或C-4光合机制的后果，我们比较了在C-3，C-1-C-4，C-4-like，和C-4种的双子叶植物黄菊的细胞间分布的活性和mRNA的APR。六种黄菊属植物的APR活性、mRNA水平和蛋白质积累的测量显示，APR活性、半胱氨酸和谷胱甘肽水平在C-4样和C-4物种中显著高于C3和C-3-C-4物种。ATP硫酸化酶和APR mRNA在C-4种三脉黄菊叶肉和维管束鞘细胞中的水平相当。免疫金电子显微镜表明，在这两种细胞类型的叶绿体中的APR蛋白的存在。这些研究结果，从文献中的结果一起，表明，本地化的同化硫酸盐还原在维管束鞘细胞中并不普遍存在的C-4植物，因此既不是一个先决条件，也不是C-4光合作用的后果。
The activity of the enzymes catalyzing the first two steps of sulfate assimilation, ATP sulfurylase and adenosine 5'-phosphosulfate reductase (APR), are confined to bundle sheath cells in several C-4 monocot species. With the aim to analyze the molecular basis of this distribution and to determine whether it was a prerequisite or a consequence of the C-4 photosynthetic mechanism, we compared the intercellular distribution of the activity and the mRNA of APR in C-3, C-1-C-4, C-4-like, and C-4 species of the dicot genus Flaveria. Measurements of APR activity, mRNA level, and protein accumulation in six Flaveria species revealed that APR activity, cysteine, and glutathione levels were significantly higher in C-4-like and C-4 species than in C3 and C-3-C-4 species. ATP sulfurylase and APR mRNA were present at comparable levels in both mesophyll and bundle sheath cells of C-4 species Flaveria trinervia. Immunogold electron microscopy demonstrated the presence of APR protein in chloroplasts of both cell types. These findings, taken together with results from the literature, show that the localization of assimilatory sulfate reduction in the bundle sheath cells is not ubiquitous among C-4 plants and therefore is neither a prerequisite nor a consequence of C-4 photosynthesis.