Oxylipin biosynthetic gene families of Cannabis sativa.

Cannabis sativa is a global multi-billion-dollar cash crop with numerous industrial uses, including in medicine and recreation where its value is largely owed to the production of pharmacological and psychoactive metabolites known as cannabinoids. Often underappreciated in this role, the lipoxygenase (LOX)-derived green leaf volatiles (GLVs), also known as the scent of cut grass, are the hypothetical origin of hexanoic acid, the initial substrate for cannabinoid biosynthesis. The LOX pathway is best known as the primary source of plant oxylipins, molecules analogous to the eicosanoids from mammalian systems. These molecules are a group of chemically and functionally diverse fatty acid-derived signals that govern nearly all biological processes including plant defense and development. The interaction between oxylipin and cannabinoid biosynthetic pathways remains to be explored. Despite their unique importance in this crop, there has not been a comprehensive investigation focusing on the genes responsible for oxylipin biosynthesis in any Cannabis species. This study documents the first genome-wide catalogue of the Cannabis sativa oxylipin biosynthetic genes and identified 21 LOX, five allene oxide synthases (AOS), three allene oxide cyclases (AOC), one hydroperoxide lyase (HPL), and five 12-oxo-phytodienoic acid reductases (OPR). Gene collinearity analysis found chromosomal regions containing several isoforms maintained across Cannabis, Arabidopsis, and tomato. Promoter, expression, weighted co-expression genetic network, and functional enrichment analysis provide evidence of tissue- and cultivar-specific transcription and roles for distinct isoforms in oxylipin and cannabinoid biosynthesis. This knowledge facilitates future targeted approaches towards Cannabis crop improvement and for the manipulation of cannabinoid metabolism.

The underdog invader: Breeding system and colony genetic structure of the dark rover ant (Brachymyrmex patagonicus Mayr).

Ants are among the most successful species at invading new environments. Their success undeniably comes from their various modes of reproduction and colony breeding structures, which influence their dispersal ability, reproductive potential, and foraging strategies. Almost all invasive ant species studied so far form supercolonies, a dense network of interconnected nests comprising numerous queens, without aggression toward non-nestmates. This strategy results in invasive colonies that are able to grow extremely fast and large while avoiding intraspecific competition, allowing them to monopolize environmental resources and outcompete native species. Here, we developed and used 10 microsatellite markers to investigate the population structure and breeding system of the dark rover ant Brachymyrmex patagonicus Mayr in its introduced range. We determined whether this species exhibits a supercolonial structure by assessing whether different nests belonged to the same genetic colony. We inferred its dispersal ability by investigating isolation by distance and estimated the numbers of queens per colonies and mating per queen through parent-offspring inferences. We found that most of the colonies of B. patagonicus were comprised of a single nest, headed by a single queen. Each nest was distinct from one another, without isolation by distance, which suggests strong dispersal ability through nuptial flights. These features are commonly observed in noninvasive and native ant species, but they are surprising for a successful invasive ant, as they strongly differ from other invasive ants. Overall, we discuss how this seemingly unfavorable strategy for an invasive ant might favor the invasive success of the dark rover ant in the United States.

Alate trap-based assessment of Formosan subterranean termite (Isoptera: Rhinotermitidae) dispersal flight phenology associated with an urbanized barrier island ecosystem.

During 2009, 2010, and 2011, the reproductive dispersal flight phenology of Formosan subterranean termites (Coptotermes formosanus Shiraki) was assessed on Galveston Island, TX, via LED light-based termite alate traps. In all three years, traps were deployed at sampling sites before the initiation of C. formosanus dispersal flights, and retrieved weekly until the cessation flights. In total, 45, 102, and 90 traps were deployed during 2009, 2010, and 2011, respectively. In all years, C. formosanus flights began during the second full week of May; however, peak dispersal flight activity occurred 2 wk earlier in 2009 and 2011 than in 2010. Significantly more alates were collected during the 2009 flight peak than in 2010 and 2011 despite the fact that greater than twice the number of traps were deployed in 2010 and 2011, versus 2009. Additionally, a greater percentage of traps collected C. formosanus alates in 2009 (71.1%) than in 2010 (38.2%) or 2011 (20.0%). A relatively inexpensive trap design (∼US$25.00 per trap) was developed for this project. The traps used in this work yielded results that were similar to those of other researchers using a variety of different trap designs. It is hoped that these results will allow for more targeted surveillance of C. formosanus dispersal flights by residents and pest management professionals at this location and elsewhere.