Project description:The oomycete Pythium oligandrum is a potential biocontrol agent to control a wide range of fungal and oomycetes-caused diseases such as Pythium myriotylum-caused rhizome rot in ginger leading to reduced yields and compromised quality. Previously, P. oligandrum has been studied for its plant growth-promoting potential by auxin production and induction of disease resistance by elicitors such as oligandrin. Volatile organic compounds (VOCs) play beneficial roles in sustainable agriculture by enhancing plant growth and resistance. We investigated the contribution of P. oligandrum-produced VOCs on plant growth and disease suppression by initially using N. benthamiana plants for screening. P. oligandrum VOCs significantly enhanced tobacco seedling and plant biomass content. Screening of the individual VOCs showed that 3-octanone and hexadecane promoted the growth of tobacco seedlings. The total VOCs from P. oligandrum also enhanced the shoot and root growth of ginger plants. Transcriptomic analysis showed a higher expression of genes related to plant growth hormones, and stress responses in the leaves of ginger plants exposed to P. oligandrum VOCs. The concentrations of plant growth hormones such as auxin, zeatin, and gibberellic acid were higher in the leaves of ginger plants exposed to P. oligandrum VOCs. In a ginger disease biocontrol assay, the VOC-exposed ginger plants infected with P. myriotylum had lower levels of disease severity. We conclude that this study contributes to understanding the growth-promoting mechanisms of P. oligandrum on ginger and tobacco, priming of ginger plants against various stress and the mechanisms of action of P. oligandrum as a biocontrol agent.
Project description:Current protection strategies against the fungal pathogen Botrytis cinerea rely on a combination of conventional fungicides and host genetic resistance. Defence elicitors can stimulate plant defence mechanisms through a phenomenon known as priming. Priming results on a faster and/or stronger expression of resistance upon pathogen attack. This work aims to study priming of a commercial formulation of the elicitor Chitosan. Treatments with Chitosan result in induced resistance in solanaceous and brassicaceous plants. Large-scale transcriptomic analysis in this study revealed that Chitosan primes gene expression at early time-points after infection. Four conditions were analysed using microarrays: (i) water-treated and non-infected plants (Water + Mock); (ii) Chitosan-treated and non-infected plants (Chitosan + Mock); (iii) water-treated and B. cinerea-infected plants (Water + B. cinerea); (iv) Chitosan-treated and B. cinerea-infected plants (Chitosan + B. cinerea). Inoculations were performed four days after treatment with Chitosan, and leaf discs from four independent plants (biological replicates) per treatment were sampled at 6 h, 9 h and 12 h post-inoculation (hpi) with water mock or B. cinerea spores.
Project description:Oomycetes, such as the broad host-range necrotrophic plant pathogen Pythium myriotylum, cause devastating crop losses. We have previously identified P. myriotylum as the major pathogen infecting ginger (Zingiber officinale) rhizomes in China with symptoms of Pythium soft rot (PSR) disease. Ginger is an important crop with global production estimated at approximately three million metric tonnes with about 20% of this production in China. To better understand how P. myriotylum infects ginger, transcriptomic analysis was performed on two P. myriotylum isolates (SWQ7 and SL2) infecting ginger leaves. From both of the isolates, there was a clear separation between the transcriptome replicates from the mycelial control condition and those from the infection of the ginger leaf. In SWQ7 and SL2, there were 2,110 and 2,513 genes upregulated during infection of ginger, respectively. Of the putative effectors, a subset of the NEP1-like toxin protein (NLP) effectors were highly induced during the infection of ginger leaves. Insights from the transcriptome highlight the important role of a subset of plant cell wall degrading enzymes (PCWDEs) and effectors in the pathogenicity of P. myriotylum towards ginger. The surprisingly large numbers of P. myriotylum PCWDEs and effectors within the genome may be due to the broad host-range of P. myriotylum whereby particular subsets of the PCWDEs and effectors are required for pathogenicity towards particular hosts.
Project description:Comparative analysis of micro-RNA (miRNA) in ginger-derived nanoparticles and ginger donor tissue using next-generation sequencing (NGS). The ginger-derived nanoparticles were prepared by differential ultracentrifuges. We mapped about 30 to 50 million sequence reads to the plant miRNA database and identified total of 2228 miRNAs including 532 miRNAs higher in nanoparticles and 1,280 miRNAs higner in tissue.
Project description:A mutant of SG511 (wild type isolate), resistant to the presence of chitosan (polycationic molecule) was obtained following serial passage experiments resistance to chitosan exposition. Transcriptomic experiments showed alteration in the expression of genes involved in the cell wall regulon resulting in the modification of susceptibility phenotype against cell wall active antibiotics
Project description:Colitis is the common pathological lesion of inflammatory bowel diseases, the major chronic inflammatory diseases of intestinal tracts in humans. In this study, we investigated the therapeutic effects of ginger extract and its component zingerone in mice with 2,4,6-trinitrobenzene sulfonic acid (TNBS)-induced colitis. Mice were administered with TNBS and/or various amounts of ginger and zingerone by an intrarectal route. The severity of colitis was evaluated by colonic weight/length ratio, macroscopic lesion, and histological examination. The mechanisms of ginger and zingerone were further elucidated by DNA microarray, ex vivo imaging, and immunohistochemical staining. Our data showed that treatment with ginger extract and zingerone ameliorated TNBS-induced colonic inflammation and injury in a dose-dependent manner. Pathway analysis of ginger- and zingerone-regulated gene expression profiles showed that ginger and zingerone significantly regulated cytokine-related pathways. Network analysis showed that nuclear factor-κB (NF-κB) and interleukin-1β (IL-1β) were key molecules involved in the expression of ginger- and zingerone-affected genes. Ex vivo imaging and immunohistochemical staining further verified that ginger and zingerone suppressed TNBS-induced NF-κB activation and decreased the NF-κB and IL-1β protein levels in the colon. In conclusion, our data showed that ginger improved the TNBS-induced colitis in mice via modulation of NF-κB activity and IL-1β signaling pathway. Moreover, zingerone might be the active component of ginger responsible for the amelioration of colitis induced by TNBS. A total of 24 mice was randomly divided into four groups of six mice: mock, mice were given with 0.1 ml of 50% ethanol; TNBS, mice were given with 250 mg/kg TNBS in 0.1 ml of 50% ethanol; TNBS/ginger, mice were administered with mixtures containing 250 mg/kg TNBS and various amounts of ginger extract in 0.1 ml of 50% ethanol; TNBS/zingerone, mice were given with mixtures containing 250 mg/kg TNBS and various amounts of zingerone in 0.1 ml of 50% ethanol. Mice were sacrificed seven days later for histochemical staining, RNA extraction, and ex vivo imaging.
Project description:Colitis is the common pathological lesion of inflammatory bowel diseases, the major chronic inflammatory diseases of intestinal tracts in humans. In this study, we investigated the therapeutic effects of ginger extract and its component zingerone in mice with 2,4,6-trinitrobenzene sulfonic acid (TNBS)-induced colitis. Mice were administered with TNBS and/or various amounts of ginger and zingerone by an intrarectal route. The severity of colitis was evaluated by colonic weight/length ratio, macroscopic lesion, and histological examination. The mechanisms of ginger and zingerone were further elucidated by DNA microarray, ex vivo imaging, and immunohistochemical staining. Our data showed that treatment with ginger extract and zingerone ameliorated TNBS-induced colonic inflammation and injury in a dose-dependent manner. Pathway analysis of ginger- and zingerone-regulated gene expression profiles showed that ginger and zingerone significantly regulated cytokine-related pathways. Network analysis showed that nuclear factor-κB (NF-κB) and interleukin-1β (IL-1β) were key molecules involved in the expression of ginger- and zingerone-affected genes. Ex vivo imaging and immunohistochemical staining further verified that ginger and zingerone suppressed TNBS-induced NF-κB activation and decreased the NF-κB and IL-1β protein levels in the colon. In conclusion, our data showed that ginger improved the TNBS-induced colitis in mice via modulation of NF-κB activity and IL-1β signaling pathway. Moreover, zingerone might be the active component of ginger responsible for the amelioration of colitis induced by TNBS.
Project description:Cancer stem cells (CSCs), a small population of cancer cells, have been considered to be the origin of cancer initiation, recurrence, and metastasis. Tumor microenvironment provides crucial signals for CSCs to maintain stem cell properties and promote tumorigenesis. Therefore, establishment of an appropriate cell culture system to mimic the microenvironment for CSC studies is an important issue. In this study, we grew colon and hepatocellular carcinoma (HCC) cells on chitosan membranes and evaluated the tumor progression by transwell migration, drug resistance, microarray, and RT-PCR analysis. We also evaluated the CSC properties by flow cytometry, sphere forming assay, luciferase reporter assay, western blot, and gene knockdown. Experimental results showed that culturing cancer cells on chitosan increased cell motility, drug resistance, quiescent population, self-renewal capacity, and the expression levels of stemness and CSC marker genes, such as OCT4, NANOG, CD133, CD44, and EpCAM. Furthermore, we demonstrated that chitosan might activate canonical Wnt/β-catenin-CD44 axis signaling in CD44positive colon cancer cells and noncanonical Wnt-STAT3 signaling in CD44negative HCC cells. In conclusion, chitosan as culture substrates activated the essential signaling of CSCs and promoted CSC properties. The chitosan culture system provides a convenient platform for the research of CSC biology and screening of anticancer drugs.
Project description:Chitosan has been widely used in food industry as a weight-loss aid and a cholesterol-lowering agent. Previous studies have shown that chitosan affects metabolic responses and contributes to anti-diabetic, hypocholestermic, and blood glucose-lowering effects; however, the in vivo targeting sites and mechanisms of chitosan remain to be clarified. In this study, we constructed transgenic mice which carried the luciferase genes driven by peroxisome proliferator-activated receptor (PPAR), a key regulator of fatty acid and glucose metabolism. Bioluminescent imaging of PPAR transgenic mice was applied to report the organs that chitosan acted on, and gene expression profiles of chitosan-targeted organs were further analyzed to elucidate the mechanisms of chitosan. Bioluminescent imaging showed that constitutive PPAR activities were detected in brain and gastrointestinal tract. Administration of chitosan significantly activated the PPAR activities in brain and stomach. Microarray analysis of brain and stomach showed that several pathways involved in lipid and glucose metabolism were regulated by chitosan. Moreover, the expression levels of metabolism-associated genes like apolipoprotein B (apoB) and ghrelin genes were down-regulated by chitosan. In conclusion, these findings suggested the feasibility of PPAR bioluminescent imaging-guided transcriptomic analysis on the evaluation of chitosan-affected metabolic responses in vivo. Moreover, we newly identified that downregulated expression of apoB and ghrelin genes were novel mechanisms for chitosan-affected metabolic responses in vivo . Mice (6 to 8 weeks old) were subcutaneously injected saline or 0.2 g/kg chitosan. Chitosan oligosaccharide lactate (MW=4000-6000, >90% deacetylation) was purchased from Sigma-Aldrich (St. Louis, MO, USA) and dissolved in DDW. For rosiglitazone treatment, mice were orally administered 50 mg/kg rosiglitazone. Mice were then imaged for the luciferase activity or sacrificed for microarray analysis at indicated periods.
Project description:We treated Arabidopsis seedlings with chitosan and carried out a transcript profiling analysis (GeneChip microarrays) in order to identify genes and transcription factors regulated by chitosan. The results showed that jasmonate and defense responsive genes, camalexin and lignin biosynthetic genes were among genes up-regulated by chitosan. Several transcription factors are also strongly induced by chitosan. The results suggested that chitosan can be used as a strong elicitor of defense pathways.