A sex-chromosome mutation in Silene latifolia

Silene latifolia is dioecious, yet rare hermaphrodites have been found, and such natural mutants can provide valuable insight into genetic mechanisms. Here, we describe a hermaphrodite-inducing mutation that is almost certainly localized to the gynoecium-suppression region of the Y chromosome in S. latifolia. The mutant Y chromosome was passed through the megaspore, and the presence of two X chromosomes was not necessary for seed development in the parent. This result supports a lack of degeneration of the Y chromosome in S. latifolia, consistent with the relatively recent formation of the sex chromosomes in this species. When crossed to wild-type plants, hermaphrodites performed poorly as females, producing low seed numbers. When hermaphrodites were pollen donors, the sex ratio of offspring they produced through crosses was biased towards females. This suggests that hermaphroditic S. latifolia would fail to thrive and potentially explains the rarity of hermaphrodites in natural populations of S. latifolia. These results indicate that the Y chromosome in Silene latifolia remains very similar to the X, perhaps mostly differing in the primary sex determination regions

A new physical mapping approach refines the sex-determining gene positions on the Silene latifolia Y-chromosome

Sex chromosomes are particularly interesting regions of the genome for both molecular genetics and evolutionary studies; yet, for most species, we lack basic information, such as the gene order along the chromosome. Because they lack recombination, Y-linked genes cannot be mapped genetically, leaving physical mapping as the only option for establishing the extent of synteny and homology with the X chromosome. Here, we developed a novel and general method for deletion mapping of non-recombining regions by solving "the travelling salesman problem", and evaluate its accuracy using simulated datasets. Unlike the existing radiation hybrid approach, this method allows us to combine deletion mutants from different experiments and sources. We applied our method to a set of newly generated deletion mutants in the dioecious plant Silene latifolia and refined the locations of the sex-determining loci on its Y chromosome map

Conserved expression of a TASSELSEED2 homolog in the tapetum of the dioecious Silene latifolia and Arabidopsis thaliana

Plant Journal123515-526PLJU

Review of Flowering Control in Industrial Hemp

Hemp ( Cannabis sativa L.) is a dioecious annual that commences its reproductive cycle when photoperiods are shorter than a critical length. Photoperiod-sensitive varieties grown in low latitudes with short-day lengths tend to produce early flowering, short plants affecting the yield and quality of the fiber. The photoperiodic sensitivity of the crop could be controlled by the activation or deactivation of genes triggered by the change in light duration perceived by photoreceptive pigments. The sexual dimorphism of Cannabisis genetically determined by the XY chromosomal mechanismal though sexual morphology is primarily a result of endogenous plant growth regulator levels that fluctuate in response to environmental variables. Occurrence of occasional hermaphroditic flowers and monoecious plants are probably the result of these fluctuations. Understanding the mechanisms of photoperiodicity and sexual inheritance contributes to advances in breeding and crop management that may underpin the expansion of the commercial cultivation of the crop in nontraditional agroecological domains