Yu Jie, Ma Pei-Jun, Shi Ding-Ji, Li Shi-Ming, Wang Chang-Lu
School of Marin Science & Engineering, Tianjin University of Science & Technology, Tianjin 300457, China.
J Integr Plant Biol. 2008 Aug;50(8):929-40. doi: 10.1111/j.1744-7909.2008.00679.x.
It has now believed that chloroplasts arose from cyanobacteria, however, during endosymbiosis, the photosynthetic genes in chloroplasts have been reduced. How these changes occurred during plant evolution was the focus of the present study. Beginning with photosystem I (PSI) genes, a homologous comparison of amino acid sequences of 18 subunits of PSI from 10 species of cyanobacteria, chloroplasts in 12 species of eucaryotic algae, and 28 species of plants (including bryophytes, pteridophytes, gymnospermae, dicotyledon and monocotyledon) was undertaken. The data showed that 18 genes of PSI can be divided into two groups: Part I including seven genes (psaA, psaB, psaC, psaI, psaJ, ycf3 and ycf4) shared both by cyanobacteria and plant chloroplasts; Part II containing another 11 genes (psaD, psaE, psaF, psaK, psaL, psaM, btpA, ycf37, psaG, psaH and psaN) appeared to have diversified in different plant groups. Among Part I genes, psaC, psaA and psaB had higher homology in all species of cyanobacteria and chloroplasts. Among Part II genes, only psaG, psaH and psaN emerged in seed plants.
现在人们认为叶绿体起源于蓝细菌，然而，在共生过程中，叶绿体中的光合基因已经减少。这些变化在植物进化过程中是如何发生的是本研究的重点。从光系统I（PSI）基因开始，对10种蓝细菌、12种真核藻类叶绿体以及28种植物（包括苔藓植物、蕨类植物、裸子植物、双子叶植物和单子叶植物）的PSI的18个亚基的氨基酸序列进行了同源性比较。数据表明，PSI的18个基因可分为两组：第一组包括7个基因（psaA、psaB、psaC、psaI、psaJ、ycf3和ycf4），蓝细菌和植物叶绿体都有；第二组包含另外11个基因（psaD、psaE、psaF、psaK、psaL、psaM、btpA、ycf37、psaG、psaH和psaN），似乎在不同的植物类群中有所分化。在第一组基因中，psaC、psaA和psaB在所有蓝细菌和叶绿体物种中具有较高的同源性。在第二组基因中，只有psaG、psaH和psaN出现在种子植物中。
