Different Transcriptional Response to <em>Xanthomonas citri</em> subsp. <em>citri</em> between Kumquat and Sweet Orange with Contrasting Canker Tolerance

<div><p>Citrus canker disease caused by <em>Xanthomonas citri</em> subsp. <em>citri</em> (Xcc) is one of the most devastating biotic stresses affecting the citrus industry. Meiwa kumquat (<em>Fortunella crassifolia</em>) is canker-resistant, while Newhall navel orange (<em>Citrus sinensis</em> Osbeck) is canker-sensitive. To understand the molecular mechanisms underlying the differences in responses to Xcc, transcriptomic profiles of these two genotypes following Xcc attack were compared by using the Affymetrix citrus genome GeneChip. A total of 794 and 1324 differentially expressed genes (DEGs) were identified as canker-responsive genes in Meiwa and Newhall, respectively. Of these, 230 genes were expressed in common between both genotypes, while 564 and 1094 genes were only significantly expressed in either Meiwa or Newhall. Gene ontology (GO) annotation and Singular Enrichment Analysis (SEA) of the DEGs showed that genes related to the cell wall and polysaccharide metabolism were induced for basic defense in both Meiwa and Newhall, such as chitinase, glucanase and thaumatin-like protein. Moreover, apart from inducing basic defense, Meiwa showed specially upregulated expression of several genes involved in the response to biotic stimulus, defense response, and cation binding as comparing with Newhall. And in Newhall, abundant photosynthesis-related genes were significantly down-regulated, which may be in order to ensure the basic defense. This study revealed different molecular responses to canker disease in Meiwa and Newhall, affording insight into the response to canker and providing valuable information for the identification of potential genes for engineering canker tolerance in the future.</p> </div

Functional categorization of the common upregulated and downregulated genes in ‘Meiwa’ and ‘Newhall’ based on the GO annotation.

<p>Functional categorization of the common upregulated and downregulated genes in ‘Meiwa’ and ‘Newhall’ based on the GO annotation.</p

Significantly enriched cation binding related genes in ‘Meiwa’ specifically regulated gene cluster.

<p>#N/A: no signals were detected.</p

Number of differentially expressed genes in ‘Meiwa’ and ‘Newhall’ after statistical analysis.

<p>(A) Number of significantly upregulated and downregulated genes in ‘Meiwa’ and ‘Newhall’. (B–C) Venn diagram shows the number of upregulated (B) and downregulated (C) genes that are expressed in common or in special between ‘Meiwa’ and ‘Newhall’.</p

Significantly enriched genes involved in polysaccharide metabolism that are regulated in common between ‘Meiwa’ and ‘Newhall’ or specifically regulated in ‘Meiwa’.

<p>#N/A: no signals were detected.</p

Verification of the microarray results by semi-quantitative RT-PCR.

<p>(A) RT-PCR results of the genes. The cDNA of ‘Meiwa’ and ‘Newhall’ leaves sampled at 0 (designated as M0 and N0, respectively) and 5 (designated as M5 and N5, respectively) days post inoculation (DPI) was amplified with specific primers of the selected genes, using Actin as a control. (B) Comparison of the expression ratios (M5/M0 and N5/N0) between RT-PCR analysis and the microarray data. The expression ratios were calculated by quantifying the band density using the Quantity One software.</p

Comparison of canker disease development in ‘Meiwa’ and ‘Newhall’.

<p>(A) Leaves of ‘Meiwa’ and ‘Newhall’ were pinprick-inoculated with citrus canker bacterium and periodically observed within 7 d, and the pictures were taken at 5 and 7 days post inoculation (DPI). (B) Quantitative comparison of the bacterial population at the inoculation sites of ‘Meiwa’ and ‘Newhall’ leaves after 6 days inoculation.</p

Significantly enriched GO terms (adjust <i>P</i><0.05) of specifically regulated genes in ‘Meiwa’ after Singular Enrichment Analysis.

<p>Significantly enriched GO terms (adjust <i>P</i><0.05) of specifically regulated genes in ‘Meiwa’ after Singular Enrichment Analysis.</p

Significantly enriched genes related to biotic stimulus response that are regulated in common between ‘Meiwa’ and ‘Newhall’ or specifically regulated in ‘Meiwa’.

<p>#N/A: no signals were detected.</p

Will Sofosbuvir/Ledipasvir (Harvoni) Be Cost-Effective and Affordable for Chinese Patients Infected with Hepatitis C Virus? An Economic Analysis Using Real-World Data

<div><p>Background</p><p>Little is known on the cost-effectiveness of novel regimens for hepatitis C virus (HCV) compared with standard-of-care with pegylated interferon (pegIFN) and ribavirin (RBV) therapy in developing countries. We evaluated cost-effectiveness of sofosbuvir/ledipasvir for 12 weeks compared with a 48-week pegIFN-RBV regimen in Chinese patients with genotype 1b HCV infection by economic regions.</p><p>Methods</p><p>A decision analytic Markov model was developed to estimate quality-adjusted-life-years, lifetime cost of HCV infection and incremental cost-effectiveness ratios (ICERs). SVR rates and direct medical costs were obtained from real-world data. Parameter uncertainty was assessed by one-way and probabilistic sensitivity analyses. Threshold analysis was conducted to estimate the price which can make the regimen cost-effective and affordable.</p><p>Results</p><p>Sofosbuvir/ledipasvir was cost-effective in treatment-experienced patients with an ICER of US$21,612. It varied by economic regions. The probability of cost-effectiveness was 18$18,185 to make the regimen cost-effective in all patients at WTP of one time GDP per capita. The price has to be US$105 to make the regimen affordable in average patients in China.</p><p>Conclusion</p><p>Sofosbuvir/ledipasvir regimen is not cost-effective in most Chinese patients with genotype 1b HCV infection. The results vary by economic regions. Drug price of sofosbuvir/ledipasvir needs to be substantially reduced when entering the market in China to ensure the widest accessibility.</p></div