Alonso J M, Chamarro J, Granell A
Instituto de Biología Molecular y Celular de Plantas, Universidad Politécnica de Valencia-Consejo Superior de Investigaciones Científicas, Spain.
Plant Mol Biol. 1995 Dec;29(6):1211-21. doi: 10.1007/BF00020463.
The sequence and expression of mRNA homologous to a cDNA encoding a non-photosynthetic ferredoxin (Fd1) from Citrus fruit was investigated. The non-photosynthetic nature of this ferredoxin was deduced from: (1) amino acid sequence alignments showing better scores with non-photosynthetic than with photosynthetic ferredoxins, (2) higher expression in tissues containing plastids other than chloroplast such as petals, young fruits, roots and peel of fully coloured fruits, and (3) the absence of light-dark regulation characteristic of photosynthetic ferredoxins. In a phylogenetic tree constructed with higher-plant ferredoxins, Citrus fruit ferredoxin clustered together with root ferredoxins and separated from the photosynthetic ferredoxins. Non photosynthetic (root and fruit) ferredoxins, but not the photosynthetic ferredoxins, have their closest homologs in cyanobacteria. Analysis of ferredoxin genomic organization suggested that non-photosynthetic ferredoxins exist in Citrus as a small gene family. Expression of Fd1 is developmentally regulated during flower opening and fruit maturation, both processes may be mediated by ethylene in Citrus. Exogenous ethylene application also induced the expression of Fd1 both in flavedo and leaves. The induction on non-photosynthetic ferredoxins could be related with the demand for reducing power in non-green, but biosynthetically active, tissues.
对与柑橘果实中一种非光合铁氧还蛋白（Fd1）编码cDNA同源的mRNA序列及表达情况进行了研究。这种铁氧还蛋白的非光合性质可从以下方面推断得出：（1）氨基酸序列比对显示，其与非光合铁氧还蛋白的得分比对光合铁氧还蛋白的得分更高；（2）在含有除叶绿体之外的质体的组织中，如花瓣、幼果、根以及成熟果实的果皮中，其表达量更高；（3）不存在光合铁氧还蛋白所具有的明暗调节特性。在用高等植物铁氧还蛋白构建的系统发育树中，柑橘果实铁氧还蛋白与根铁氧还蛋白聚在一起，与光合铁氧还蛋白分开。非光合（根和果实）铁氧还蛋白，而非光合铁氧还蛋白，在蓝细菌中有其最相近的同源物。对铁氧还蛋白基因组结构的分析表明，非光合铁氧还蛋白在柑橘中以一个小基因家族的形式存在。Fd1的表达在开花和果实成熟过程中受到发育调控，这两个过程在柑橘中可能都由乙烯介导。外源施加乙烯也会诱导Fd1在黄皮层和叶片中的表达。对非光合铁氧还蛋白的诱导可能与非绿色但具有生物合成活性的组织对还原力的需求有关。
