Acer truncatum (purpleblow maple) is a woody tree species that produces seeds with high levels of valuable fatty acids (especially nervonic acid). However, the lack of a complete genome sequence has limited both basic and applied research on A. truncatum. We describe a high-quality draft genome assembly comprising 633.28 Mb (contig N50 = 773.17 kb; scaffold N50 = 46.36 Mb) with at least 28 438 predicted genes. The genome underwent an ancient triplication, similar to the core eudicots, but there have been no recent wholegenome duplication events. Acer yangbiense and A. truncatum are estimated to have diverged about 9.4 million years ago. A combined genomic, transcriptomic, metabonomic, and cell ultrastructural analysis provided new insights into the biosynthesis of very long-chain monounsaturated fatty acids. In addition, three KCS genes were found that may contribute to regulating nervonic acid biosynthesis. The KCS paralogous gene family expanded to 28 members, with 10 genes clustered together and distributed in the 0.27-Mb region of pseudochromosome 4. Our chromosome-scale genomic characterization may facilitate the discovery of agronomically important genes and stimulate functional genetic research on A. truncatum. Furthermore, the data presented also offer important foundations from which to study the molecular mechanisms influencing the production of nervonic acids.

Waterlogging limits plant growth and yield. We investigated the effects of waterlogging stress on leaf photosynthesis, chlorophyll fluorescence, antioxidant capacity, chloroplast ultrastructure, and yield of sorghum (Sorghum bicolor L.). Two sorghum cultivars, Jinuoliang01 (JN01, waterlogging-tolerant cultivar) and Jinza31 (JZ31, waterlogging-sensitive cultivar) were subjected to a 12-d waterlogging treatment; the plants of the two cultivars which were not subjected to waterlogging were used as control (CK), respectively. After waterlogging treatment, the yield of JZ31 and JN01 decreased by 72.3 and 52.9%, the net photosynthetic rate of JZ31 and JN01 decreased by 61.8 and 39.0%, respectively, compared with CK. The chlorophyll content was higher, PSII was more stable, and chloroplast structure remained more intact in JN01 than that in JZ31 under waterlogging. This was due to the higher peroxidase and catalase activities and nonphotochemical quenching in JN01 compared to JZ31. Therefore, greater antioxidant capacity and nonphotochemical quenching could alleviate damage to PSII and chloroplast ultrastructure to maintain higher net photosynthetic rate under waterlogging. This may be an important waterlogging-tolerance mechanism of sorghum.

Appropriate application of nitrogen (N) can alleviate the salt stress-induced damage on plants. This study explores the changes of nitrogen requirement in feeding annual ryegrass seedlings under mild salt concentrations (50 mM, 100 mM) plus its underlying mitigation mechanism. Results showed that low salt concentration decreased N requirement as observed from the increment in plant height and biomass at a relative low N level (2.0 mM not 5.0 mM). Under salt treatment, especially at 50 mM NaCl, the OJIP (Chl a fluorescence induction transient) curve and a series of performance indexes (PIABS, RC/CS0, ET0/CS0, ϕE0, ϕ0) peaked whereas DI0/RC, Vj and M0 were the lowest under moderately low N level (2.0 mM). In addition, under salt stress, moderately low N application could maintain the expression of NR (nitrate reductase) and GS (glutamine synthetase) encoding genes at a relatively stable level but had no effect on the expression of detected NRT (nitrate transporter) gene. The seedlings cultured at 2.0 mM N also exhibited the highest activity of CAT and POD antioxidant enzymes and the lowest MDA content and EL under relative low level of salt treatment. These results indicated that mild salt treatment of annual ryegrass seedlings might reduce N requirement while moderately low N application could promote their growth via regulating photosynthesis, alleviating ROS-induced (reactive oxygen species) damage and maintenance of N metabolism. These results also can provide useful reference for nitrogen application in moderation rather than in excess on annual ryegrass in mild or medium salinity areas through understanding the underlying response mechanisms.

Background: Non-small cell lung cancer (NSCLC) accounts for approximately 85% of all lung cancers. Berberine (BBR), an isoquinoline alkaloid, is commonly used in traditional Chinese medicine. Previous studies have shown that BBR has a potential anti-tumor effect. However, the mechanisms of BBR on mitochondrial function in anti-lung cancer remain unknown. The aim of this study was to explore mitochondrial function in anti-tumor mechanisms of BBR in NSCLC. Methods:The NSCLCs were cultured and treated with various doses (40, 80, 120 µg/mL) of BBR for 24 and 48 h. Cell viability was evaluated using Cell Counting Kit-8 (CCK-8). Cell apoptosis, reactive oxygen species (ROS) and mitochondrial membrane potential (MMP) were detected by flow cytometry. Relative protein expression was examined by western blot and immunohistochemical (IHC) analysis.Results: BBR potently suppressed NSCLC cells growth by inducing apoptosis in a dose-and timedependent manner. BBR induced apoptosis in NSCLC cells as evidenced by caspase-3 cleavage, cytochrome c release, and mitochondrial membrane depolarization. BBR-induced, dose-dependent induction of apoptosis was accompanied by sustained phosphorylation of c-jun-NH2-kinase (JNK) and the JNK inhibitor (SP600125) significantly suppressed BBR-induced apoptosis, N-acetyl cysteine (NAC), a ROS scavenger, was sufficient to both suppress apoptosis signal-regulating kinase 1 (ASK1) and JNK activation and disrupt apoptotic induction. Conclusions:The results suggest that BBR induces apoptosis of NSCLC cells via ROS-mediated ASK1/ JNK activation and the mitochondrial pathway.

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