RNA-seq study of sexual reproduction in the diatom Skeletonema marinoi induced by a change in salinity

The aim of the experiment was to study the gene expression changes occurring when cells of the diatom Skeletonema marinoi undergo sexual reproduction. In this species, sex can be induced by an environmental trigger, specifically a change in salinity of the cultivation media. In diatoms the unique mode of cell division with unequal inheritance of the rigid cell wall components determines a progressive cell size reduction as cells divide. Large cells above a given size threshold are not competent for sex, on the other hand small cells, under appropriate conditions, can undergo sexual reproduction. RNA-seq included three experimental conditions: a) large cells above the sexualization size threshold, grown at standard salinity (control condition: no sex, no salinity stress); b) large cells above the sexualization size threshold transferred to higher salinity (treatment 1: no sex, salinity stress); c) small cells below the sexualization size threshold transferred to higher salinity (treatment 2: sex, salinity stress).