Chromosome-level genome assemblies of five Prunus species and genome-wide association studies for key agronomic traits in peach

Prunus species include many important perennial fruit crops,such as peach,plum,apricot,and related wild species.Here,we report de novo genome assemblies for five species,including the cultivated species peach(Prunus persica),plum(Prunus salicina),and apricot(Prunus armeniaca),and the wild peach species Tibetan peach(Prunus mira)and Chinese wild peach(Prunus davidiana).The genomes ranged from 240 to 276 Mb in size,with contig N50 values of 2.27−8.30Mb and 25,333−27,826 protein-coding gene models.As the phylogenetic tree shows,plum diverged from its common ancestor with peach,wild peach species,and apricot~7 million years ago(MYA).We analyzed whole-genome resequencing data of 417 peach accessions,called 3,749,618 high-quality SNPs,577,154 small indels,31,800 deletions,duplications,and inversions,and 32,338 insertions,and performed a structural variant-based genome-wide association study(GWAS)of key agricultural traits.From our GWAS data,we identified a locus associated with a fruit shape corresponding to the OVATE transcription factor,where a large inversion event correlates with higher OVATE expression in flat-shaped accessions.Furthermore,a GWAS revealed a NAC transcription factor associated with fruit developmental timing that is linked to a tandem repeat variant and elevated NAC expression in early-ripening accessions.We also identified a locus encoding microRNA172d,where insertion of a transposable element into its promoter was found in double-flower accessions.Thus,our efforts have suggested roles for OVATE,a NAC transcription factor,and microRNA172d in fruit shape,fruit development period,and floral morphology,respectively,that can be connected to traits in other crops,thereby demonstrating the importance of parallel evolution in the diversification of several commercially important domesticated species.In general,these genomic resources will facilitate functional genomics,evolutionary research,and agronomic improvement of these five and other Prunus species.We believe that structural variant-based GWASs can also be used in other plants,animal species,and humans and be combined with deep sequencing GWASs to precisely identify candidate genes and genetic architecture components.

Effects of fabrication methods on deformability and microstructure of Mg-Zn-Zr wrought alloy

The effects of fabrication processing methods on the workability of Mg-Zn-Zr wrought magnesium alloy(ZK60A) were investigated based on the microstructure and inherent internal defects. Three different billets, semi-continuously cast, semi-continuously cast and subsequently extruded, and die-cast, were fabricated and uniaxially compressed at elevated temperatures and two different strain rates to determine the deformation capabilities. The grain structure of the billets was investigated using electron backscatter diffraction(EBSD) and transmission electron microscopy(TEM). The internal defects were inspected by an X-ray scanner. The enhanced deformability was observed in semi-continuously cast billet compared to the one fabricated by conventional die-casting, and the subsequent extrusion further improved the deformability.

Exploring Win-Wins from Trade-Offs? Co-Benefits of Coalbed Methane Utilization for the Environment, Economy and Safety

With policy incentives for the coalbed methane in energy industry,coalbed methane from coal production has been effectively improved by technology innovations in coalbed methane extraction and utilization.The progress of coalbed methane promotes the clean construction of energy system and contributes to carbon neutrality target.To quantitatively measure the contributions of the coalbed methane in energy industry,this paper builds a carbon emissions accounting system for coalbed methane in China and assesses the historical co-benefits of coalbed methane utilization from the aspects of emissions reduction,safety and economy.By using the parameters of gas content,raw coal production,gas extraction rate and utilization rate over the years,emissions reduction potential and economic viability of coal seam gas are estimated and the safety benefits of coal mine gas extraction are analyzed by using data for gas accidents and economic losses.The results reveal that with the increase in raw coal production,the great emission reduction potential of coalbed methane is expected to benefit clean energy system and the development of carbon neutrality by means of policy incentives and technology innovations.The co-benefit evaluation indicates the huge profitability of coalbed methane from 2012 to 2015 and the significance of emissions reduction and safety gain internalization.Safety benefits are obvious in the negative exponential function between the annual drainage quantities of coalbed methane and annual death tolls from coal mine gas accidents.Based on these results,relevant suggestions are put forward for sustainable development of the coalbed methane in energy industry.