条斑紫菜色彩突变体的诱导、分离和特性分析

Isolation and characterization of pigmentation mutants in Porphyra yezoensis Ueda (Bangiales,Rhodophyta)

条斑紫菜叶状体的原生质体经化学诱变剂──N -甲基 -N’ -硝基 -N -亚硝基胍 (MNNG)处理后 ,在它们的再生叶状体中 ,出现了少量色彩发生变异的点状变异体。它们的色彩变异细胞呈点状无规则地与野生细胞或其它变异细胞镶嵌在一起。这类变异体的单孢子萌发成单色变异 (或野生色 )叶状体以及与母体相似的点状变异体。利用单色变异叶状体分离出绿色 (yel) ,浅桔黄色 (och)以及深桔红色 (bus)等三个突变株。突变株的叶状体活体吸收光谱以及藻红蛋白和藻蓝蛋白的含量与野生型相比均存在着明显的差异。经突变体与野生型杂交实验证明 ,突变体yel和och均含一个与色彩变化有关并且符合孟德尔遗传规律的隐性变异基因。相关变异基因的着丝粒距离 ,在突变体yel和och中分别为 1 1 .5和 1 5 .

A few color variegated blades appeared in the blades regenerated from the MNNG treated protoplasts of Porphyra yezoensis Ueda. They consisted of the wild type and color mutated cells which spottedly scattered. The monospores released from these spottedly variegated blades, developed into single colored blades (variants and the wild type one) and the spottedly variegated blades, which were very similar to the mother blade. From the single colored variants, three mutant strains were obtained. They showed green, light yellow orange and dull red orange in color, and were designated as yel, och and bus, respectively. The mutant strains were stable in color in both gametophytic blade and conchocelis phases. In the two phases, each mutant strain showed characteristic differences in the in vivo absorption spectra, and had different contents of major photosynthetic pigments (chlorophyll α, phycoerythrin and phycocyanin) as compared with the wild type and with each other. By crossing the mutant with the wild type, it was found that the color phenotypes of yel and och resulted from only a single recessive mutation respectively. The mutated gene associating with the color in yel or och is respectively calculated to be 11.5 or 15.8 centimorgans from the chromosome's centsomere.