Researchers from Harvard University and elsewhere consider the genetic underpinnings of early flowering adaptations that have arisen in autotetraploid Arabidopsis arenosa plants growing along railway sites in the Bavarian Alps for a paper appearing in PLOS Genetics. Using a combination of genetic mapping, genome sequencing, and transcriptome sequencing on A. arenosa seeds from seven exposed or sheltered railway sites, the team saw signs of selection at both introgressed alleles and rare standing variation in cosmopolitan Arabidopsis railway plants and secondary hybrid plants colonizing these areas. When it came to flowering time, meanwhile, the investigators note that genes such as FLC and CONSTANS, previously linked to weediness traits, appear to undergo allelic divergence that affects flowering time.
A team from Argentina and Mexico explores the genetic diversity and population structure of sandflies from the Lutzomyia longipalpis species complex, which can act as vectors for Leishmania infantum parasites that causes visceral leishmaniasis in parts of the Americas. As they report in PLOS Neglected Tropical Diseases, the researchers profiled two genetic markers in Lu longipalpis from half a dozen locations in Argentina, identifying two main genetic clusters in that country. Compared with available markers from Lu. longipalpis sandflies in public databases, the new sequences highlighted eight haplogroups in species complex representatives in the neotropical region and made it possible to retrace the most recent shared ancestor of these sandflies, which the authors placed at roughly 700,000 years ago.
In PLOS One, Italian researchers present findings from a genome sequencing analysis of Pyrenochaeta lycopersici, a fungal pathogen that affects tomato and related plants. With the help of single-molecule real-time sequencing, the team put together a gapless genome assembly spanning nearly 63 million bases, which was analyzed alongside a previous short read sequence-based draft genome for P. lycopersici to get a clearer look at repetitive element representation and other features that had been difficult to discern from the more fragmented draft genome. Despite producing a significantly larger genome assembly, the authors saw a comparable gene content, for example, as well as repetitive sequences making up some 30 percent of the genome.