坛紫菜(Pyropia haitanensis)核糖体基因簇序列的测定

The Nuclear Ribosomal DNA (nrDNA) Cistron Sequence of Pyropia haitanensis (Bangiales, Rhodophyta)

坛紫菜是我国独有的栽培紫菜物种,而目前对坛紫菜分类学层面上仍缺乏有效的分子鉴定技术.本研究通过PCR方法,对采自福建省莆田海区坛紫菜样品核糖体基因簇序列进行了测定,目的是为坛紫菜分类及种质鉴定提供分子生物学证据.测定结果表明,坛紫菜样品的18Sr DNA的全长序列长度为2953 bp;28S r DNA部分序列3603 bp,且不含内含子;5.8S r DNA长度为158 bp,该区域的5’端和3’端十分保守,在紫菜属中差异较小;ITS1的长度为334 bp;ITS2为678bp.已经测定IGS区的部分长度为3555 bp,该区域存在复杂二级结构.通过对坛紫菜核糖体基因簇序列的分析表明,其能够成为紫菜分类鉴定与系统演化的分子标记.

Pyropia haitanensis is a unique cuhivated laver in China, while the lack of effective molecular identifi- cation technology affects the taxonomy of P. haitanensis. The study sequenced the nuclear ribosomal DNA （nrD- NA） cistron sequence of P. haitanensis from Putian, Fujiang Province by polymerase chain reaction （PCR）, in or- der to provide molecular biological evidence for classification and germplasm identification of P. haitanensis. The results show that each unit is composed of the small-subunit （SSU） rRNA gene of which the full length is 2953bp, that the partial sequence of the large-subunit （LSU） rRNA gene of which the length is 3603bp without any introns, that the length of the 5.8S rRNA gene is 158bp, and the 5＇ and 3＇ terminal sequences of the genic regions of the ribosomal cistron are extremely conservative in the case of the genus of Pyropia, that the length of ITS1 is 334bp and ITS2 is 678bp and that the partial sequence of IGS is 3555bp, due to a complicated secondary structure existing in IGS region, which makes sequencing untoward. Though the analysis of nuclear ribosom- al DNA sequence, it can be a molecular maker for the taxonomic identification of Pyropia.