Spermidine activates adipose tissue thermogenesis through autophagy and fibroblast growth factor 21.

Spermidine exerts protective roles in obesity, while the mechanism of spermidine in adipose tissue thermogenesis remains unclear. The present study first investigated the effect of spermidine on cold-stimulation and ß3-adrenoceptor agonist-induced thermogenesis in lean and high-fat diet-induced obese mice. Next, the role of spermidine on glucose and lipid metabolism in different types of adipose tissue was determined. Here, we found that spermidine supplementation did not affect cold-stimulated thermogenesis in lean mice, while significantly promoting the activation of adipose tissue thermogenesis under cold stimulation and ß3-adrenergic receptor agonist treatment in obese mice. Spermidine treatment markedly enhanced glucose and lipid metabolism in adipose tissues, and these results were associated with the activated autophagy pathway. Moreover, spermidine up-regulated fibroblast growth factor 21 (FGF21) signaling and its downstream pathway, including PI3K/AKT and AMPK pathways in vivo and in vitro. Knockdown of Fgf21 or inhibition of PI3K/AKT and AMPK pathways in brown adipocytes abolished the thermogenesis-promoting effect of spermidine, suggesting that the effect of spermidine on adipose tissue thermogenesis might be regulated by FGF21 signaling via the PI3K/AKT and AMPK pathways. The present study provides new insight into the mechanism of spermidine on obesity and its metabolic complications, thereby laying a theoretical basis for the clinical application of spermidine.

Bifidobacterium animalis subsp. lactis LKM512 Alleviates Inflammatory Bowel Disease in Larval Zebrafish by Reshaping Microbiota.

Inflammatory bowel disease (IBD) is a worldwide issue, and the increased incidence has brought a heavy burden to patients and society. Gut microbiota is involved in the pathogenesis of IBD, and targeting the microbiota, such as probiotics, has emerged as a potential therapy for the treatment of IBD. Here, the effect of Bifidobacterium animalis ssp. lactis LKM512 (LKM512), an anti-aging probiotic, on dextran sulfate sodium salt (DSS)-induced IBD in larval zebrafish was determined. Supplementation of LKM512 promoted the survival rate of the larvae, together with increased locomotor activities and body length. In addition, LKM512 treatment enhanced mucus secretion and alleviated intestinal injury, and these results were associated with the upregulation of mucin-related and downregulation of inflammatory markers. Moreover, LKM512 increased the diversity of the microbiota and ameliorated the dysbiosis by increasing the abundance of Bacteroidetes and Firmicutes and reducing the abundance of Proteobacteria. Specifically, the abundance of beneficial bacteria, including the short-chain fatty-acids (SCFAs)-producing genera Lachnospiraceae_NK4A136_group, Muribaculaceae, and Alloprevotella, was increased by LKM512, while the abundance of harmful genera, such as Pseudomonas, Halomonas, and Escherichia-Shigella, was reduced by LKM512. Consistent with these findings, the microbial functions related to metabolism were partly reversed by LKM512, and importantly, fermentation of short-chain fatty acids-related functions were enhanced by LKM512. Therefore, LKM512 might be one potential probiotic for the prevention and treatment of IBD, and further studies that clarify the mechanism of LKM512 would promote the application of LKM512.

Characterization of a new gene for resistance to wheat powdery mildew on chromosome 1RL of wild rye Secale sylvestre.

KEY MESSAGE: PmSESY, a new wheat powdery mildew resistance gene was characterized and genetically mapped to the terminal region of chromosome 1RL of wild rye Secale sylvestre. The genus Secale is an important resource for wheat improvement. The Secale species are usually considered as non-adapted hosts of Blumeria graminis f. sp. tritici (Bgt) that causes wheat powdery mildew. However, as a wild species of cultivated rye, S. sylvestre is rarely studied. Here, we reported that 25 S. sylvestre accessions were susceptible to isolate BgtYZ01, whereas the other five confer effective resistance to all the tested isolates of Bgt. A population was then constructed by crossing the resistant accession SESY-01 with the susceptible accession SESY-11. Genetic analysis showed that the resistance in SESY-01 was controlled by a single dominant gene, temporarily designated as PmSESY. Subsequently, combining bulked segregant RNA-Seq (BSR-Seq) analysis with molecular analysis, PmSESY was mapped into a 1.88 cM genetic interval in the terminus of the long arm of 1R, which was closely flanked by markers Xss06 and Xss09 with genetic distances of 0.87 cM and 1.01 cM, respectively. Comparative mapping demonstrated that the corresponding physical region of the PmSESY locus was about 3.81 Mb in rye cv. Lo7 genome, where 30 disease resistance-related genes were annotated, including five NLR-type disease resistance genes, three kinase family protein genes, three leucine-rich repeat receptor-like protein kinase genes and so on. This study gives a new insight into S. sylvestre that shows divergence in response to Bgt and reports a new powdery mildew resistance gene that has potential to be used for resistance improvement in wheat.

Using the 6RLKu Minichromosome of Rye (Secale cereale L.) to Create Wheat-Rye 6D/6RLKu Small Segment Translocation Lines with Powdery Mildew Resistance.

Long arms of rye (Secale cereale L.) chromosome 6 (6RL) carry powdery mildew resistance genes. However, these sources of resistance have not yet been successfully used in commercial wheat cultivars. The development of small segment translocation chromosomes carrying resistance may result in lines carrying the 6R chromosome becoming more commercially acceptable. However, no wheat-rye 6RL small segment translocation line with powdery mildew resistance has been reported. In this study, a wheat-rye 6RLKu minichromosome addition line with powdery mildew resistance was identified, and this minichromosome was derived from the segment between L2.5 and L2.8 of the 6RLKu chromosome arm. Following irradiation, the 6RLKu minichromosome divided into two smaller segments, named 6RLKumi200 and 6RLKumi119, and these fragments participated in the formation of wheat-rye small segment translocation chromosomes 6DS/6RLKumi200 and 6DL/6RLKumi119, respectively. The powdery mildew resistance gene was found to be located on the 6RLKumi119 segment. Sixteen 6RLKumi119-specific markers were developed, and their products were cloned and sequenced. Nucleotide BLAST searches indicated that 14 of the 16 sequences had 91⁻100% similarity with nine scaffolds derived from 6R chromosome of S. cereale L. Lo7. The small segment translocation chromosome 6DL/6RLKumi119 makes the practical utilization in agriculture of powdery mildew resistance gene on 6RLKu more likely. The nine scaffolds are useful for further studying the structure and function of this small segment.