XVI International Botanical Congess

In the isogamous green alga Chlamydomonas reinhardtii, the chloroplast (cp) genome is transmitted from the mt+ parent, while the mitochondrial (mt) genes are believed to be inherited from the mt- parent. Cp nucleoids have been visualized by DAPI staining, and the preferential digestion of the mt- cp nucleoids has been observed in young zygotes. But the mt nucleoids have never been visualized, and their behavior is only deduced from genetic and biochemical studies. We discover that the mt and cp nucleoids can be visualized simultaneously in living cells, using the fluorescent dye SYBR Green I. By observing the behaviors of mt and cp nucleoids in living zygotes, it is directly shown that the mt nucleoids are transmitted biparentally while the mt- cp nucleoids disappeared preferentially.