Identification of <i>CkSNAP33</i>, a gene encoding synaptosomal-associated protein from <i>Cynanchum komarovii</i>, that enhances Arabidopsis resistance to <i>Verticillium dahliae</i>

<div><p>SNARE proteins are essential to vesicle trafficking and membrane fusion in eukaryotic cells. In addition, the SNARE-mediated secretory pathway can deliver diverse defense products to infection sites during exocytosis-associated immune responses in plants. In this study, a novel gene (<i>CkSNAP33</i>) encoding a synaptosomal-associated protein was isolated from <i>Cynanchum komarovii</i> and characterized. CkSNAP33 contains Qb- and Qc-SNARE domains in the N- and C-terminal regions, respectively, and shares high sequence identity with AtSNAP33 from <i>Arabidopsis</i>. <i>CkSNAP33</i> expression was induced by H₂O₂, salicylic acid (SA), <i>Verticillium dahliae</i>, and wounding. Arabidopsis lines overexpressing CkSNAP33 had longer primary roots and larger seedlings than the wild type (WT). Transgenic Arabidopsis lines showed significantly enhanced resistance to <i>V</i>. <i>dahliae</i>, and displayed reductions in disease index and fungal biomass, and also showed elevated expression of <i>PR1</i> and <i>PR5</i>. The leaves of transgenic plants infected with <i>V</i>. <i>dahliae</i> showed strong callose deposition and cell death that hindered the penetration and spread of the fungus at the infection site. Taken together, these results suggest that <i>CkSNAP33</i> is involved in the defense response against <i>V</i>. <i>dahliae</i> and enhanced disease resistance in Arabidopsis.</p></div

Solidarité plus forte : bulletin du Secours populaire français / directeur de publication Marc Domenech

juin 20032003/06 (N174)

Molecular and Functional Characterization of a Polygalacturonase-Inhibiting Protein from <i>Cynanchum komarovii</i> That Confers Fungal Resistance in Arabidopsis

<div><p>Compliance with ethical standards: This study did not involve human participants and animals, and the plant of interest is not an endangered species.</p><p>Polygalacturonase-inhibiting proteins (PGIPs) are leucine-rich repeat proteins that plants produce against polygalacturonase, a key virulence agent in pathogens. In this paper, we cloned and purified CkPGIP1, a gene product from <i>Cynanchum komarovii</i> that effectively inhibits polygalacturonases from <i>Botrytis cinerea</i> and <i>Rhizoctonia solani</i>. We found the expression of <i>CkPGIP1</i> to be induced in response to salicylic acid, wounding, and infection with <i>B</i>. <i>cinerea</i> and <i>R</i>. <i>solani</i>. In addition, transgenic overexpression in Arabidopsis enhanced resistance against <i>B</i>. <i>cinerea</i>. Furthermore, CkPGIP1 obtained from transgenic Arabidopsis inhibited the activity of <i>B</i>. <i>cinerea</i> and <i>R</i>. <i>solani</i> polygalacturonases by 62.7–66.4% and 56.5–60.2%, respectively. Docking studies indicated that the protein interacts strongly with the B1-sheet at the N-terminus of the <i>B</i>. <i>cinerea</i> polygalacturonase, and with the C-terminus of the polygalacturonase from <i>R</i>. <i>solani</i>. This study highlights the significance of CkPGIP1 in plant disease resistance, and its possible application to manage fungal pathogens.</p></div

Spleen Stiffness Is Superior to Liver Stiffness for Predicting Esophageal Varices in Chronic Liver Disease: A Meta-Analysis

<div><p>Background and Aims</p><p>Liver stiffness (LS) and spleen stiffness (SS) are two most widely accessible non-invasive parameters for predicting esophageal varices (EV), but the reported accuracy of the two predictors have been inconsistent across studies. This meta-analysis aims to evaluate the diagnostic performance of LS and SS measurement for detecting EV in patients with chronic liver disease (CLD), and compare their accuracy.</p><p>Methods</p><p>Pubmed/Medline, Embase, Cochrane Library and Ovid were searched for all studies assessing SS and LS simultaneously in EV diagnosis. A total of 16 studies including 1892 patients were included in this meta-analysis, and the pooled statistical parameters were calculated using the bivariate mixed effects models.</p><p>Results</p><p>In detection of any EV, for LS measurement, the summary sensitivity was 0.83 (95% confidence interval [CI]: 0.78–0.87), and the specificity was 0.66 (95% CI: 0.60–0.72). While for SS measurement, the pooled sensitivity and specificity was 0.88 (95% CI: 0.83–0.92) and 0.78 (95% CI: 0.73–0.83). The summary receiver operating characteristic (SROC) curve values of LS and SS were 0.81 (95% CI: 0.77–0.84) and 0.88 (95% CI: 0.85–0.91) respectively, and the results had statistical significance (P<0.01). The diagnostic odds ratio (DOR) of SS (25.73) was significantly higher than that of LS (9.54), with the relative DOR value was 2.48 (95%CI: 1.10–5.60), P<0.05.</p><p>Conclusions</p><p>Under current techniques, SS is significantly superior to LS for identifying the presence of EV in patients with CLD. SS measurement may help to select patients for endoscopic screening.</p></div

Forest plot of individual study evaluates of sensitivity and specificity for any esophageal varices diagnosis.

<p>The base vertical imaginary line indicates the combined effects. (A) Accuracy of liver stiffness measurement for estimating the presence of esophageal varices. (B) Accuracy of spleen stiffness for detecting the presence of any esophageal varices in chronic liver disease.</p

Phylogenetic tree of SNAP25 proteins.

<p>The phylogenetic tree was constructed using the neighbor-joining method with MEGA 5.1, and bootstrap values from 1,000 replicates are indicated at the nodes.</p

Inhibitory activity of crude protein extracts from wild type and transgenic Arabidopsis.

<p>Inhibitory activity was measured against <i>Botrytis cinerea</i> (<b>A</b>) and <i>Rhizoctonia solani</i> polygalacturonase (<b>B</b>). a-c, 15 μL crude enzyme + 15 μg crude protein extract from wild type and transgenic Arabidopsis lines 9 and 14; d-f, 15 μL crude enzyme + 15 μg heat-denatured crude protein extract from wild type and transgenic Arabidopsis lines 9 and 14; g, crude PGs. <b>C.</b> Inhibition rate of crude protein extracts from wild type and transgenic Arabidopsis. Error bars indicate standard error (n = 3). **, <i>P</i> < 0.01 by least significant difference against wild type.</p

Protein sequence alignment of CkSNAP33 with other SNAP25 proteins.

<p>HsSNAP25a (AAH10647.1) and HsSNAP29 (O95721.1) from <i>Homo sapiens</i>, OsSNAP32 (AAW82752.1) from <i>Oryza sativa</i> L., HvSNAP34 (AAP79417.1) from <i>Hordeum vulgare</i>, and AtSNAP33 (Q9S7P9.1) from <i>Arabidopsis thaliana</i>. Conserved residues are shaded in black and similar residues in gray. Positions in Qb-and Qc-SNARE domains that contribute to stabilizing ionic or hydrophobic interaction with other SNARE proteins are marked using asterisks and dots, respectively. The four cysteine residues involved in palmitoylation and membrane association of SNAP25 are indicated using arrow. Multiple amino acid sequence analyses were performed using Clustal Omega and the multiple alignment file was shaded using the BoxShade program.</p

The PGIP-specific consensus sequence xxLxLxx.NxLx..GxIPxxLxxL.xxL in leucine-rich repeat units of CkPGIP1.

<p>Secondary structure elements (sheets B1, B2, and 3₁₀-helix) are indicated for a homology model of CkPGIP1, which is based on PvPGIP2 (1OGQ) [<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0146959#pone.0146959.ref026" target="_blank">26</a>]. Putative glycosylation sites are doubly underlined, while conserved C residues are marked using diamonds.</p

Phylogenetic analysis of CkPGIP1 and other known PGIPs.

<p>Amino acid sequences of CkPGIP1 (red box) and other known PGIPs were obtained from GenBank. The neighbor-joining tree was built in MEGA 5.1 based on a multiple sequence alignment.</p