A viral protein competitively bound to rice CIPK23 inhibits potassium absorption and facilitates virus systemic infection in rice.

Potassium (K+) plays a crucial role as a macronutrient in the growth and development of plants. Studies have definitely determined the vital roles of K+ in response to pathogen invasion. Our previous investigations revealed that rice plants infected with rice grassy stunt virus (RGSV) displayed a reduction in K+ content, but the mechanism by which RGSV infection subverts K+ uptake remains unknown. In this study, we found that overexpression of RGSV P1, a specific viral protein encoded by viral RNA1, results in enhanced sensitivity to low K+ stress and exhibits a significantly lower rate of K+ influx compared to wild-type rice plants. Further investigation revealed that RGSV P1 interacts with OsCIPK23, an upstream regulator of Shaker K+ channel OsAKT1. Moreover, we found that the P1 protein recruits the OsCIPK23 to the Cajal bodies (CBs). In vivo assays demonstrated that the P1 protein competitively binds to OsCIPK23 with both OsCBL1 and OsAKT1. In the nucleus, the P1 protein enhances the binding of OsCIPK23 to OsCoilin, a homologue of the signature protein of CBs in Arabidopsis, and facilitates their trafficking through these CB structures. Genetic analysis indicates that mutant in oscipk23 suppresses RGSV systemic infection. Conversely, osakt1 mutants exhibited increased sensitivity to RGSV infection. These findings suggest that RGSV P1 hinders the absorption of K+ in rice plants by recruiting the OsCIPK23 to the CB structures. This process potentially promotes virus systemic infection but comes at the expense of inhibiting OsAKT1 activity.

[Inhibitory effect of Glehniae Radix petroleum ether part on TGF-ß1-induced epithelial mesenchymal transition in A549 cells].

To study the inhibitory effect of Glehniae Radix petroleum ether part on TGF-ß1-induced epithelial mesenchymal transition in non-small cell lung cancer A549 and its possible mechanism. With type Ⅱ epithelial cells of lung cancer A549 as the research object, the experiment was performed in 5 µg•L⁻¹ TGF-ß1-induced epithelial mesenchymal transition model,and blank control group, model group and Glehniae Radix petroleum ether group were set up. MTT assay was carried out to detect the effect of petroleum ether extract of Glehniae Radix on the survival of A549 cells. A549 cells induced by TGF-ß1(5 µg•L⁻¹) was intervened by different polar parts of Glehniae Radix, Real-time quantitative polymerase chain reaction(RT-qPCR) was used to analyze mRNA expressions of the epithelial mesenchymal transition markers, such as ColⅠ,E-cadherin,Vimentin and α-SMA. Enzyme linked immunosorbent assay(ELISA) was used to detect hydroxyproline(HYP) level. The migration and invasion abilities of cells were detected through wound scratch assay. According to the experimental results, the petroleum ether extract of Glehniae Radix could inhibit the growth of A549 cells in a concentration-dependent manner. Compared with model group, Glehniae Radix petroleum ether part group could effectively inhibit mRNA expressions of ColⅠ,Vimentin and α-SMA, but improve expression of E-cadherin.Glehniae Radix petroleum ether part could reduce the content of hydroxyproline in cells and inhibit the migration of A549 cells.Therefore, the petroleum ether extract of Glehniae Radix can effectively inhibit the occurrence of epithelial mesenchymal transition induced by TGF-ß1 induced alveolar epithelial cells, and Glehniae Radix petroleum ether part may be a potential drug for idiopathic pulmonary fibrosis. The mechanism may be achieved through the regulation of ColⅠ, Vimentin, α-SMA and E-cadherin.

[Structural characterization of Glehniae Radix polysaccharides using partial acid hydrolysis-hydrophilic interaction liquid chromatography-mass spectrometry].

Water-soluble polysaccharides from traditional Chinese medicine have properties of complex structure and high molecular, resulting in hardly complete their structural characterization.However, a "bottom-up" approach could solve this problem.Glehniae Radix extract was extracted with hot water and then precipitated by 40% ethanol to obtain Glehniae Radix polysaccharides (RGP). Subsequently, a partial acid hydrolysis method was carried out and the effects of acid concentration, time and temperature on hydrolysis were investigated. Under the optimum hydrolysis condition (1.5 mol•L⁻¹ trifluoroacetic acid, 4 h, and 80 ℃), RGP were hydrolyzed to characteristic oligosaccharide fragments. Futher, a hydrophilic liquid chromatography- mass spectrometry method was used for the separation and structural characterization of the polysaccharide hydrolysates. According to MS and MS/MS analysis of several standard disaccharides, a method for determining the type of polysaccharide glycosidic linkage by mass spectrometry was established. The results showed that the polysaccharide hydrolysates were linear glucan containing 1, 4-glycosidic bonds. And gluco-oligosaccharides with the degrees of polymerization (DP) of 4-11 were obtained after partial acid hydrolysis.