Aroma is an important quality trait of grapes and often the focus of consumers, viticulturists and grapevine breeders.  Kyoho is a hybrid between Vitis vinifera and Vitis labrusca with a strawberry-like scent, while 87-1 is an early-ripening mutant of Muscat hamburg, belonging to Vitis vinifera, with a rose scent.  In this study, we compared their aroma compositions and concentrations during berry development by headspace-SPME combined with gas chromatography-mass spectrometry (GC-MS), and analyzed the expression differences of enzyme-encoding genes in the LOX-HPL, MEP and MVA metabolic pathways by qRT-PCR.  Twelve esters were detected in Kyoho during the whole berry development and they were abundant after veraison, but no esters were detected in 87-1 berries.  Linalool was the dominant terpene among the 14 terpenes detected in 87-1 berries, while limited amounts of terpenes were detected in Kyoho berries.  qRT-PCR analysis indicated that the low expression of VvAAT might explain the low content of ester volatiles in 87-1 berries, and the low expression of coding genes in the MEP pathway, especially VvPNLinNer1, might be the reason for the low content of volatile terpenes in Kyoho berries.  The results from this work will promote our understanding of aroma metabolic mechanisms of grapes, and offer some suggestions for grape aromatic quality improvement.

The CRISPR/Cas9 system has been extensively used to engineer genetic loci for the generation of knockouts, insertions, and point mutations in animal models.  However, many mutations that have been reported in animals are small insertions or deletions.  This study used the CRISPR/Cas9 system to induce large DNA fragment deletions in MSTN via three guide RNAs in sheep.  This successfully achieved the precise gene editing of the ovine MSTN gene by injecting both Cas9 mRNA and sgRNAs into embryos at the one-cell stage.  Of 10 edited animals, 3 animals (30%) exhibited large genomic fragment deletions (~5 kb).  Furthermore, the body weights of these 3 animals were significantly different (P₀<0.0001, P₁₅=0.001, P₃₀=0.005, P₆₀=0.027) between lambs with large deletions and wildtype lambs.  In addition, the edited lambs were also significantly different (P₀<0.0001, P₁₅<0.0001, P₃₀=0.002, P₆₀=0.011) compared with wildtype.  These results suggest that the generated MSTN knockout sheep is a reliable and effective animal model for further study.  Furthermore, this method is time- and labor-saving, and efficient for the creation of animal models for agriculture, biology, and medicine.

 

The rapid growth of grain yield in China accelerates a discussion on whether the grain system in China is sustainable.  To answer the question, a comprehensive assessment from economic and environmental points is necessary.  This study jointly used economic analysis (ECA), emergy evaluation (EME) and carbon footprint (CF) to analyze the environmental and economic sustainability of the grain production system in China based on the national statistical data during 2000–2015.  Results showed that the costs of maize, wheat, rice and soybean had increased by 252−346% from 2000 to 2015, causing the lower profit of grain system in recent years.  The situation resulted in a serious problem on economic sustainability of grain system in China.  Meanwhile, the emergy sustainability index (ESI) of maize, wheat, rice and soybean systems were increasing during 2000–2015, and the CF on unit yield of the crops had been reduced by 10−30% in the study period.  The results reflected the improved environmental sustainability of grain system in China during 2000–2015.  Nevertheless, the emergy flow of industrial inputs for the crops were increased by 4−22% in the study period, and the CF from the inputs presented a growth rate of 16−23% as well during the same period.  The results implied that the grain system in China was relying more on fossil-based inputs.  Finally, according to the key points of cost, emergy and CF, we suggest that improving labor efficiency, advanced agricultural practices and optimizing cropping pattern will be effective ways to further improve the economic and environmental sustainability of grain system in China.