基于SSR和RSAP的龙须菜作图群体多态性标记开发与亲本间遗传距离的估计与比较

Development of polymorphic markers and estimation and comparison of genetic distances among parents of mapping population of Gracilariopsis lemaneiformis (Rhodophyta) based on SSR and RSAP analysis

遗传连锁图谱的构建是实现分子标记辅助育种与数量性状定位的必要手段,为构建龙须菜(Gracilariopsis lemaneiformis)遗传连锁图谱提供多态性分子标记,本实验共采用400对SSR引物和91对RSAP引物对组合,对龙须菜两个F1代配子体作图群体的亲本进行了多态性标记筛选,并对4个亲本间的遗传距离进行了评估。得到的SSR多态性标记在GL-F3/GLM8间为15个,GL-F6/GL-M9间为8个;多态性RSAP标记在GL-F3/GL-M8间为88个;GLF6/GL-M9间为93个。分析了基于SSR、RSAP技术的两对亲本间的遗传距离,SSR结果显示GL-F3/GL-M8间遗传距离为0.071 2,GL-F6/GL-M9间的遗传距离为0.043 6;RSAP结果显示GL-F3/GL-M8间遗传距离为0.228 4,GL-F6/GL-M9间的遗传距离为0.253 7。结果表明,在引物组合平均覆盖的位点和引物组合平均产生的多态性方面,RSAP均远高于SSR,在GL-F3/GL-M8间RSAP分别是SSR的4.48与12.13倍,在GL-F6/GL-M9间RSAP分别是SSR的5.81与25.5倍,RSAP标记更适合应用于龙须菜的遗传距离估计和资源的遗传多样性研究。本研究揭示出作图群体亲本间遗传多样性特征,SSR与RSAP分子标记的开发为龙须菜遗传连锁图谱的构建奠定了基础。

Gracilariopsis lemaneiformis is an important agarophyte, which is economically important. The industrialization of Gracilariopsis lemaneiformis started 20 years ago and has become one of the most important aquaculture in China. At present, the breeding of this species depends heavily on selective and other traditional breeding approaches. The molecular breeding system which is more efficient has not yet been established. The construction of genetic linkage map is urgent for the molecular marker assistant breeding and mapping of quantitative traits. Totally 400 pairs of SSR primers and 91 pairs of RSAP primer combinations were screened for parents of two mapping populations to provide polymorphic molecular markers for the construction of genetic linkage map. The genetic distances among four parents were evaluated. 15 polymorphic markers between GL-F3 and GL-M8 and 8 polymorphic markers between GL-F6 and GL-M9 were obtained by SSR screening. 88 polymorphic markers between GL-F3 and GL-M8 and 93 polymorphic markers between GL-F6 and GL-M9 were obtained by RSAP screening. The development of these markers set the basis for construction of genetic linkage map. The genetic distance revealed by SSR between GL-F3 and GL-M8 was 0. 071 2, while that between GL-F6 and GL-M9 was 0. 043 6 and the genetic distance revealed by RSAP between GL-F3 and GL-M8 was 0. 228 4,while that between GL-F6 and GL-M9 was 0. 253 7. The average covering loci and producing polymorphic of per primer combinations were much higher from RSAP than from SSR analysis,the RSAP is 4.48 times and 12.13 times of SSR between GL-F3 and GL-M8,respectively while it showed 5.81 times and 25.5 times between GL-F6 and GL-M9, respectively. RSAP markers were better than SSR in evaluating the genetic distance and genetic diversity of resources of G. lemaneiformis. The genetic difference among parents of mapping population of G. lemaneiformis was proved. The development of SSR and RSAP markers set a foundation for the construction of genetic linkage map. The study revealed low genetic diversity in this species and other approaches, such as mutagenesis, cell engineering and transgenic were suggested to be exploited in further breeding attempts.