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Jia H.,Nanjing Agricultural University | Zhao P.,Nanjing Agricultural University | Wang B.,Nanjing Agricultural University | Tariq P.,Nanjing Agricultural University | And 5 more authors.
Plant Molecular Biology Reporter | Year: 2015

Polyphenols are secondary metabolites widely present in plants which benefit to human health. In the present study we analyzed the changes of polyphenol contents during strawberry fruit development as well as changes of polyphenol oxidase (PPO). The results depicted that the polyphenol content showed a decreasing trend with the fruit development. The pH value impacts the PPO activity, and in strawberry fruit the optimal pH for the PPO activity was 4.5. Meanwhile, PPO activity kept decreasing with the development of the fruit flesh and achenes. The damaged fruit enhanced the PPO activity. We found four PPO genes encoding the PPO in the strawberry that had different expression levels in tissues. The overexpression of the FaPPO1 genes improved the PPO activity in strawberry fruit and delays the fungus infection process. The FaPPO1 gene expression changes had affected the pathogen-related gene expression, such as PAL, SOD, POD, BG, and Chitinase genes. The fruit damage induced the FaPPO1 gene expression, and the abscisic acid and methyl jasmonic were also involved in the regulation of FaPPO1 gene expression. The FaPPO1 and FaPPO2 gene expressions were regulated both by abiotic stresses of low temperature, NaCl, and H2O2 and biotic stresses of powdery mildew and gray mold. Understanding the regulation mechanism of PPO will be helpful and provide meaningful ideas in future for strawberry breeders. © 2015 Springer Science+Business Media New York Source

Ouyang W.,Jiangsu Academy of Science | Ouyang W.,Nanjing Agricultural University | Wang Y.,Jiangsu Academy of Science | Zhou Y.,Jiangsu Academy of Science | And 3 more authors.
Shengwu Gongcheng Xuebao/Chinese Journal of Biotechnology | Year: 2010

Protective immune response of the available IBD vaccine is insufficient to fully protect against the prevailing strain of the infectious bursal disease virus (IBDV). Such a vaccination escape IBDV field isolate idenfied from Anhui province of China in December 2007, where IBD broke out at 2 weeks post vaccination. The IBDV vp2 gene was cloned into pFastBacHTA donor plasmid, followed by generation of the recombinant bacmid DNA pBac-VP2. The latter was used to transfect insect cell Sf9 with Lipofectamine to produce recombinant baculovirus vBac-VP2. The Sf9 cells infected with vBac-VP2 were stained positive against IBDV antibody using the indirect immunofluorescence assay (IFA), which was also confirmed by the detection of IBDV Vp2 protein in the infected Sf9 cells by IBDV sandwich ELISA. Western blotting revealed that the calculated protein of approximately 53 kDa was in the expressed in the insect cells. Moreover, virus-like particles (VLPs) and "inclusion body-like"structure in the infected Sf9 cells were observed under electron microscopy. We further developed an indirect ELISA for the detection of the IBDV antibodies, which was specific and sensitive. In addition, the lysates of vBac-VP2 infected cells was used to immunize 2-week-old SPF chickens, followed by challenging with the virulent IBDV, the survival rate was 30% at 14 days post primary immunization, however, the survival rate was 100% at 14 d after the booster vaccination. The ELISA antibody titers was up to 3.2×10 3 and neutralization antibody titer was 2536, significantly higher than those of one-shot vaccination, 8×10 2 and 1106, respectively. The immunized chickens did not show any clinical signs and histopathological changes of infection in 7-days trial time. The bursa/body-weight ratios were higher than those of the unimmunized control (P <0.05). The virus-like-particle recombinant Vp2 protein expressed in insect cells promises to be a novel subunit vaccine and diagnostic reagent candidate for IBDV. © 2010 CJB, All rights reserved. Source

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