Synergistic effects of TAL1 over-expression and PHO13 deletion on the weak acid inhibition of xylose fermentation by industrial Saccharomyces cerevisiae strain

In the industrial production of bioethanol from lignocellulosic biomass, a strain of Saccharomyces cerevisiae that can ferment xylose in the presence of inhibitors is of utmost importance. The recombinant, industrial-flocculating S. cerevisiae strain NAPX37, which can ferment xylose, was used as the parent to delete the gene encoding p-nitrophenylphosphatase (PHO13) and overexpress the gene encoding transaldolase (TAL1) to evaluate the synergistic effects of these two genes on xylose fermentation in the presence of weak acid inhibitors, including formic, acetic, or levulinic acids. TAL1 over-expression or PHO13 deletion improved xylose fermentation as well as the tolerance of NAPX37 to all three weak acids. The simultaneous deletion of PHO13 and the over-expression of TAL1 had synergistic effects and improved ethanol production and reduction of xylitol accumulation in the absence and presence of weak acid inhibitors.     

Programmed cell death induced by cadmium stress and/or boron deprivation in tobacco (Nicotiana tabacum L.) cultivar Bright Yellow 2 cells

Cadmium (Cd) is one of the most toxic and widespread heavy metal pollutants in soil. As an essential mineral nutrient, boron (B) plays critical roles in physiological processes of plants. In the present study, programmed cell death (PCD) induced by Cd stress and/or B deprivation was assessed and the underlying mechanisms were clarified in suspension-cultured Nicotiana tabacum L. cultivar Bright Yellow 2 (TBY-2) cells. The PCD in TBY-2 cells was analyzed by Hoechst 33258 staining and the terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) assay, and then, expression analysis of PCD-related genes was performed using quantitative real-time polymerase chain reaction (qPCR) assays. The production of reactive oxygen species (ROS) was determined using fluorescence microscopy of 2′,7′-dichlorofluorescein diacetate–labeled cells. The levels of lipid peroxides were quantified by the thiobarbituric acid–reactive substances (TBARS) method. Cadmium stress and/or B deprivation treatments induced PCD that was characterized by a significant increase in the percentage of cells stained with Hoechst 33258 or TUNEL-positive cells, and upregulation or downregulation of the expression of PCD-related genes. Treatments with Cd stress and/or B deprivation increased ROS production and the level of lipid peroxides compared to those of the control group. These data showed that in TBY-2 cells Cd stress and/or B deprivation activated ROS signaling pathways, leading to gene expression that was connected with the PCD process.

     

与美国对比分析草地贪夜蛾在我国的危害发展趋势

草地贪夜蛾是一种重大入侵害虫,自入侵云南以来,迅速在我国传播,对我国的食品安全构成了严重威胁。文章通过对比中国与美国之间气候条件、耕作模式、转基因玉米种植、农民认知情况、农药使用水平等因素分析了草地贪夜蛾在我国危害发展趋势,以提高农业工作者对防治草地贪夜蛾的重视程度,进一步为我国防治草地贪夜蛾的工作提供理论依据。     

Genome-Wide Identification and Expression Analysis of the BvSnRK2 Genes Family in Sugar Beet (Beta vulgaris L.) Under Salt Conditions

Journal of Plant Growth Regulation - The sucrose non-fermenting-1-related protein kinase 2s (SnRK2s) have been shown to play critical roles in the response to environmental stresses in higher...