Sex determination in dioecious Silene latifolia. Effects of the Y chromosome and the parasitic smut fungus (Ustilago violacea) on gene expression during flower development.

摘要

A molecular cloning approach was undertaken to the investigation of sex determination in Silene latifolia, a dioecious plant species with morphologically distinguishable sex chromosomes. A range of genes was defined that are up-regulated in male plants in response to Y chromosome sex-determination genes. Eight male-specific cDNA sequences were characterized and classified according to their expression dynamics to provide a range of molecular markers for dioecious male flower development. Genetically female S. latifolia plants undergo a partial sex reversal in response to infection by the parasitic smut fungus Ustilago violacea. This phenomenon was exploited in these studies; male-specific cDNAs were further categorized as inducible or non-inducible in female plants by smut fungus infection. Analysis of the organ-specific expression of male specific probes in male and female flowers identified a gene that is regulated in a sex-specific manner in non-reproductive floral tissues common to both maleand female plants. This is the first observation of a molecular marker for dominant effects of the Y chromosome in non-reproductive floral organs.