This study will provide a deeper understanding of the systematics of ferns and the genes that allow them to grow in shady habitats. The presence of neochrome -- a novel chimeric photoreceptor that fuses red-sensing and blue-sensing photoreceptors into a single gene -- is linked to the ability of ferns to thrive in low-light conditions. Despite its potential importance in adaptation, the evolution of neochrome has remained unexplored. This study will investigate the evolution of neochrome and test the hypothesis that the distribution of the gene is the result of recurrent horizontal gene transfer among ferns. This award will support the research and training of a female doctoral student and undergraduate researchers in diverse molecular and systematic methods.
Horizontal gene transfer (HGT) is common in prokaryotes and is often a key driver of adaptation and evolution. However, most documented examples of plant-to-plant HGT involve mitochondrial DNA and/or parasite-host transfers; only a handful of cases include functional nuclear genes, and even fewer have possible adaptive implications. Consequently, plant-to-plant HGT generally has been overlooked as a noteworthy factor in plant evolution. The aim of this research is to use targeted next-generation sequencing of neochrome from diverse fern species to further elucidate the frequency and timing of the seemingly large number of neochrome horizontal gene transfer events in ferns. Because neochrome may have played a major role in promoting the radiation of ferns under low-light environments, this study has important implications for better understanding the evolutionary significance of plant-to-plant HGT.
