淀粉质体DNA的研究现状

A Surrey of the Research on DNA

淀粉质体含有丰富的DNA,平均每个淀粉质体含有数百个基因组拷贝。其分布特点因物种而异,大都集中于拟核区,有的分散于质体内。在淀粉质体发育过程中,DNA含量不断增加,成熟期达到顶峰,以贮藏形态存在,为种子的萌发和幼苗的形态建成提供核苷酸等原料。淀粉质体DNA具有与叶绿体DNA同源的序列,存在一些表达基因,如:16SrRNA、psbA。但在抑制区域富甲基化,尤其是5-甲基胞嘧啶,碱基的甲基化在aDNA基因的表达调控中起重要作用。

Amyloplasts include abundant DNA, each of which involves hundreds of genome copies on average. The distribution of DNA is based on different species, most of which accumu late in the nucleoids, others disperse in the plastid. The number of Amyloplast DNA（aDNA） constantly increases during the development of amyloplast till the maximum in adult stage which are stored in the plastid in order to provide nucleotldes for seeds germination and seedings shapes. Amyloplast DNA, homologous to the chloroplast DNA, has some expression genes such as 16SrRNA and psbA,but a variety of methylated bases, especially 5-methylcytosine, are in the suppression areas. DNA methylation plays an important role in the regulation of amyloplast genes expressions.