Transgenic miR156 Switchgrass in the Field: Growth, Recalcitrance and Rust Susceptibility

Sustainable utilization of lignocellulosic perennial grass feedstocks will be enabled by high biomass production and optimized cell wall chemistry for efficient conversion into biofuels. MicroRNAs are regulatory elements that modulate the expression of genes involved in various biological functions in plants, including growth and development. In greenhouse studies, overexpressing a microRNA (miR156) gene in switchgrass had dramatic effects on plant architecture and flowering, which appeared to be driven by transgene expression levels. Highexpressing lines were extremely dwarfed, whereas low and moderate-expressing lines had higher biomass yields, improved sugar release and delayed flowering. Four lines with moderate or low miR156 overexpression from the prior greenhouse study were selected for a field experiment to assess the relationship between miR156 expression and biomass production over three years. We also analysed important bioenergy feedstock traits such as flowering, disease resistance, cell wall chemistry and biofuel production. Phenotypes of the transgenic lines were inconsistent between the greenhouse and the field as well as among different field growing seasons. One low expressing transgenic line consistently produced more biomass (25%–56%) than the control across all three seasons, which translated to the production of 30% more biofuel per plant during the final season. The other three transgenic lines produced less biomass than the control by the final season, and the two lines with moderate expression levels also exhibited altered disease susceptibilities. Results of this study emphasize the importance of performing multiyear field studies for plants with altered regulatory transgenes that target plant growth and development

Conflict between cultural development and wildlife conservation: A potential threat to Reeves's pheasant (Syrmaticus reevesii)

Abstract Reeves's pheasant feathers are used to make headgears for the Chinese opera—Xiqu; however, this posed a considerable threat to the bird's population before it was banned from hunting/trade. It is unclear whether Xiqu‐troupes currently use feathers from wild or captive breeding; therefore, we investigated their source and scale of feather utilization. Through interviews, we clarified the current status of feather‐use by state‐run troupes. We conducted a cluster analysis and established a “random forest” model using stable isotopes as variables to distinguish sources of feathers from Xiqu‐troupes. Annual demand for feathers in China was estimated as 1159.4 pairs. Isotope analysis revealed that feathers used by Xiqu‐troupes are likely derived from wild sources. We suggest strengthening the supervision of acquisition of Reeves's pheasant feathers and harvesting feathers through captive breeding. Stable isotope analysis can be an effective method for identifying the source of tail feathers, which will support law enforcement efforts