Breeding progress and preparedness for mass-scale deployment of perennial lignocellulosic biomass crops switchgrass, miscanthus, willow and poplar.

Genetic improvement through breeding is one of the key approaches to increasing biomass supply. This paper documents the breeding progress to date for four perennial biomass crops (PBCs) that have high output-input energy ratios: namely Panicum virgatum (switchgrass), species of the genera Miscanthus (miscanthus), Salix (willow) and Populus (poplar). For each crop, we report on the size of germplasm collections, the efforts to date to phenotype and genotype, the diversity available for breeding and on the scale of breeding work as indicated by number of attempted crosses. We also report on the development of faster and more precise breeding using molecular breeding techniques. Poplar is the model tree for genetic studies and is furthest ahead in terms of biological knowledge and genetic resources. Linkage maps, transgenesis and genome editing methods are now being used in commercially focused poplar breeding. These are in development in switchgrass, miscanthus and willow generating large genetic and phenotypic data sets requiring concomitant efforts in informatics to create summaries that can be accessed and used by practical breeders. Cultivars of switchgrass and miscanthus can be seed-based synthetic populations, semihybrids or clones. Willow and poplar cultivars are commercially deployed as clones. At local and regional level, the most advanced cultivars in each crop are at technology readiness levels which could be scaled to planting rates of thousands of hectares per year in about 5 years with existing commercial developers. Investment in further development of better cultivars is subject to current market failure and the long breeding cycles. We conclude that sustained public investment in breeding plays a key role in delivering future mass-scale deployment of PBCs.

Collecting wild Miscanthus germplasm in Asia for crop improvement and conservation in Europe whilst adhering to the guidelines of the United Nations' Convention on Biological Diversity.

BACKGROUND AND AIMS: Germplasm with diverse, agronomically relevant traits forms the foundation of a successful plant breeding programme. Since 1993, the United Nations has been advocating the implementation of the Convention on Biological Diversity (CBD) and the subsequent 2002 Bonn Guidelines as international best practice on germplasm collection and use. In 2006, a European team made an expedition to Asia to collect wild germplasm of Miscanthus, a C4 perennial rhizomatous grass, for breeding an environmentally adaptable, resilient and high-yielding bioenergy crop. We outline general aspects of germplasm collection, conservation, breeding and biomass production evaluation while following the CBD's guidelines, respecting biodiversity and conservation needs, and the ethical use of genetic resources. METHODS: Effective protocols, quarantine, methods for collecting seed and rhizomes, and a genebank for conservation were established. Versatile informatics and database architecture were used to assist in selection, flowering synchronization, crossing, evaluation, phenotyping and data integration. Approaches were formulated to comply with the CBD guidelines. KEY RESULTS: A total of 303 accessions of M. sinensis, M. sacchariflorus and M. floridulus were collected from 158 geographically and environmentally diverse locations. These species were shown to accumulate different amounts of aerial biomass due to combinations of stem count, height and thickness. Progeny from one interspecies cross accumulated more biomass in early trials and has shown double the yield performance in years 3-4 compared with the existing commercial cultivar M. × giganteus. An example of an F1 hybrid has already demonstrated the long-term potential of exploiting this collection for a breeding programme. CONCLUSIONS: By conforming to the CBD principles, the authors' international collaboration provides a practical example of implementing the CBD. The collection widened the genetic diversity of Miscanthus available to allow for breeding of novel hybrids that exhibit more diverse traits to increase yield and resilience for growth on marginal land and in climate-challenged environments.

Structure-activity relationships of modified C-terminal endomorphin-2 analogues by molecular dynamics simulations.

Motivated by recent experimental works on the modifications of endomorphin-2 (EM2, H-Tyr-Pro-Phe-Phe-NH2) to develop better painkiller, we performed structure-activity-relationship (SAR) studies to investigate modified C-terminal ligands by using molecular dynamics (MD) simulations. Specifically, instead of the CONH2 for the unmodified EM2's C-terminus, the analogue 2 with its C-terminus being CONHNH2 and analogue 3 with its C-terminus being COOMe are studied. First, a systematic conformer search was performed via the quantum chemical AM1 calculations. The cis/trans isomers of the lowest energy were hence selected as MD initial structures. We further showed that EM2s in water exhibited similar dihedral angles to those in DMSO, obtained from the NMR experiment. This similarity indicates the reliability of our MD simulations, and enables us to discuss related bioactivity. Our results showed that the interactions of the Tyr(1)-Phe(3) pair for cis-/trans-EM2s played a considerable role for structural stability. Furthermore, we utilized the chi(1) rotamers of individual aromatic side chains to examine the structural bioactivity. It is shown that this criterion to determine the conformational bioactivity toward mu-opioid receptor (MOR) is insufficient. Thus, we have further employed rotamer-combination approaches to examine the characteristics of SAR for cis-/trans-EM2s. Our results suggested that the bioactive chi(1) rotamers for Tyr(1)-Phe(3) pair remained to favor the [trans-trans] status for MOR selectivity. Therefore, based on the analysis of the chi(1) rotamers, it is suggested that the analogue 2 exhibit greater structural bioactivity for MOR than the analogue 3, and both of them be greater than unmodified EM2 for trans isomers.