A novel ß-1,3-glucanase Gns6 from rice possesses antifungal activity against Magnaporthe oryzae.

As members of the pathogenesis-related protein (PR)-2 family, ß-1,3-glucanases play pivotal roles in plant defense. Previous study showed that the rice genome contains 16 genes encoding putative ß-1,3-glucanases, and the ß-1,3-glucanases in subfamily A were deduced to be involved in plant defense. However, there was limited direct evidence. In this study, the expression of rice ß-1,3-glucanases Gns2-Gns6 belonging to subfamily A in rice plant infection with Magnaporthe oryzae was investigated, and the enhanced expression of Gns6 during infection confirmed its crucial role in the defense of rice seedlings. Enzymological characterization revealed that Gns6 preferentially hydrolyzed laminarin, pachymaran, and yeast glucan. The ß-1,3; 1,6-glucanase Gns6 exhibited a specific activity of 1.2 U/mg with laminarin as the substrate. In addition, Gns6 could hydrolyze laminarin via an endo-type mechanism, yielding a series of oligosaccharides with various degrees of polymerization that are known immune elicitors in plants. Moreover, Gns6 exhibited a significant inhibitory effect against the formation of the germ tubes and appressoria, with potential applications in plant protection. Taken together, this study shows that Gns6 is an essential effector in the defensive response of rice against pathogenic fungi.

Ethanol extract of Zhongtian hawthorn lowers serum cholesterol in mice by inhibiting transcription of 3-hydroxy-3-methylglutaryl-CoA reductase via nuclear factor-kappa B signal pathway.

Hawthorn is a berry-like fruit from the species of Crataegus. In China, it has another more famous name, Shan-Zha, which has been used to improve digestion as a traditional Chinese medicine or food for thousands of years. Moreover, during the last decades, hawthorn has received more attention because of its potential to treat cardiovascular diseases. However, currently, only fruits of C. pinnatifida and C. pinnatifida var. major are included as Shan-Zha in the Chinese Pharmacopoeia. In this study, our results showed that the ethanol extract of Zhongtian hawthorn, a novel grafted cultivar of C. cuneata (wild Shan-Zha), could markedly reduce body weight and levels of serum total cholesterol, triglyceride, low-density lipoprotein cholesterol, and liver cholesterol of hyperlipidemia mice. It could suppress the stimulation effect of high-fat diet on the transcription of 3-hydroxy-3-methylglutaryl-CoA reductase (HMGCR) and p65, and counteract the downregulation of CYP7A1 and LDLR. In addition, the results of luciferase reporter assay and Western blot showed that the transcriptional activity of HMGCR promoter was inhibited by Zhongtian hawthorn ethanol extract in a dose-dependent manner, while overexpression of p65 could reverse this transcriptional repression effect. These results suggested that Zhongtian hawthorn could provide health benefits by counteracting the high-fat diet-induced hypercholesteolemic and hyperlipidemic effects in vivo, and the mechanism underlying this event was mainly dependent on the suppressive effect of Zhongtian hawthorn ethanol extract on the transcription of HMGCR via nuclear factor-kappa B (NF-κB) signal pathway. Therefore, this novel cultivar of hawthorn cultivar which has much bigger fruits, early bearing, high yield, cold resistance, and drought resistance, might be considered as a good alternative to Shan-Zha and has great value in the food and medicine industry. In addition, to our best knowledge, this is also the first report that the extract of Crataegus could suppress the transcription of HMGCR via NF-κB signal pathway.