H2S-mediated balance regulation of stomatal and non-stomatal factors responding to drought stress in Chinese cabbage.

Increased evidence has shown that hydrogen sulfide (H2S), a novel gasotransmitter, could enhance drought resistance in plants by inducing stomatal closure, with concurrent enhancement of photosynthetic efficiency, but little is known about the mechanism behind this contradictory phenomenon. This study examined the regulating mechanism of H2S in response to drought stress from stomatal and non-stomatal factors in Chinese cabbage. The results showed that exogenous H2S could increase the accumulation of photosynthetic pigments and alleviate the damage caused by drought stress. It also regulated the expression in transcriptional level and the activity of ribulose 1,5-bisphosphate carboxylase/oxygenase (BrRuBisCO) under drought stress. The large subunit of BrRuBisCO was found to be modified by S-sulfhydration, which might be the reason for its increased enzyme activity. The fluxes of Cl-, K+, and H+ in the guard cells were detected by non-invasive micro-test techniques while under drought stress. The results indicated that H2S signaling induced a transmembrane Cl- and H+ efflux and inhibited K+ influx, and the Cl- channel was the main responders for H2S-regulated stomatal movement. In conclusion, H2S signal not only activated the ion channel proteins located in the guard cell membrane to induce stomatal closure, but also regulated the transcriptional expression and the activity of RuBisCO, a non-stomatal factor to enhance the photosynthetic efficiency of leaves. There is therefore a beneficial balance between the regulation of H2S signaling on stomatal factors and non-stomatal factors due to drought stress, which needs to be better understood to apply it practically to increase crop yields.

Oat ß-glucan ameliorates diabetes in high fat diet and streptozotocin-induced mice by regulating metabolites.

Oats are widely distributed worldwide and oat ß-glucan has positive effects on human health. Particularly, oat ß-glucan is reported to be beneficial in the management of type 2 diabetes. The aim of the present study is to investigate the effects of oat ß-glucan and its possible underlying mechanisms on diabetes in type 2 diabetic mice that was induced by streptozotocin/high-fat diet (STZ/HFD). The data indicated that oat ß-glucan significantly reduced the fasting blood glucose, improved glucose tolerance, and insulin sensitivity. The results further showed that oat ß-glucan remarkably decreased the levels of total cholesterol (TCHO), total triglyceride (TG), low-density lipoprotein cholesterol (LDL-C) and free fatty acids. Moreover, oat ß-glucan remarkably increased the hepatic glycogen content, but largely decreased the levels of aspartate aminotransferase (AST) and alanine aminotransferase (ALT) in STZ/HFD-induced diabetic mice. Histological analysis showed that oat ß-glucan alleviated visceral lesions. Finally, the metabolomic analysis indicated that the metabolic profile was remarkably changed after oat ß-glucan intervention in diabetic mice. There were 88 and 106 differential metabolites screened as biomarkers in negative ion mode (NEG) and positive ion mode (POS) after oat ß-glucan treatment, respectively. In addition, oat ß-glucan significantly affected the serum metabolites of amino acids, organic acids and bile acids. Collectively, the current study elucidates oat ß-glucan displays an effective nutritional intervention in diabetes.