Project description:The antioxidant enzyme system is the main defense system responsible for maintaining cellular reactive oxygen species (ROS) homeostasis and normal plant growth and development after saline stress. In this study, we identified and characterized the members of the SOD, APX and CAT gene families of the antioxidant enzyme system in Gymnocarpos przewalskii, using plant physiology and molecular biology methods, and analyzed the pattern of enzyme activity in response to NaCl stress. It was found that seven, six and two genes of SOD, APX and CAT gene families, respectively, were expressed in the leaf tissue of G. przewalskii, in which most of the genes were significantly upregulated under NaCl stress, and the enzymatic activities were in accordance with the gene expression. Three positive selection sites in the GpCAT1 gene can increase the hydrophilicity of the GpCAT1 protein, increase the volume of the active site and increase the affinity for H2O2, thus improving the catalytic efficiency of GpCAT1. The results of the present study provide new insights for further investigations of the evolution and function of the SOD, APX and CAT gene families in G. przewalskii and their essential roles under salt stress, and the findings will be useful for revealing the molecular mechanism of salt tolerance and breeding of salt-tolerant plants.
Project description:Northwestern China has a wealth of endemic species, which has been hypothesized to be affected by the complex paleoclimatic and paleogeographic history during Quaternary. In this paper, we used Gymnocarpos przewalskii as a model to address the evolutionary history and current population genetic structure of species in northwestern China. We employed two chloroplast DNA fragments (rps16 and psbB-psbI), one nuclear DNA fragment (ITS), and simple sequence repeat (SSRs) to investigate the spatial genetic pattern of G. przewalskii. High genetic diversity (cpDNA: h S = 0.330, h T = 0.866; ITS: h S = 0.458, h T = 0.872) was identified in almost all populations, and most of the population have private haplotypes. Moreover, multimodal mismatch distributions were observed and estimates of Tajima's D and Fu's FS tests did not identify significantly departures from neutrality, indicating that recent expansion of G. przewalskii was rejected. Thus, we inferred that G. przewalskii survived generally in northwestern China during the Pleistocene. All data together support the genotypes of G. przewalskii into three groups, consistent with their respective geographical distributions in the western regions-Tarim Basin, the central regions-Hami Basin and Hexi Corridor, and the eastern regions-Alxa Desert and Wulate Prairie. Divergence among most lineages of G. przewalskii occurred in the Pleistocene, and the range of potential distributions is associated with glacial cycles. We concluded that climate oscillation during Pleistocene significantly affected the distribution of the species.
Project description:Identification of target transcripts for the putative chloroplast RNA binding protein CFM2 in Zea mays. CFM2 was immunoprecipitated from a chloroplast extract. Chloroplast extracts were prepared from WT tissue. RNA from the pellet and from the supernatant for each pulldown was labelled with different fluoro-dyes and hybridized onto an array covering the complete maize chloroplast genome. Messages enriched in the immunoprecipitate from WT tissue are likely targets for CFM2.
Project description:Identification of target transcripts for the putative chloroplast RNA binding protein CRP1 in Zea mays. CRP1 was immunoprecipitated from a chloroplast extract. Chloroplast extracts were prepared from WT and CRP1-deficient tissue. RNA from the pellet and from the supernatant for each pulldown was labelled with different fluoro-dyes and hybridized onto an array covering the complete maize chloroplast genome. Messages enriched in the immunoprecipitate from WT tissue, but not enriched in mutant tissue are likely targets for CRP1.
2005-08-01 | E-MEXP-282 | biostudies-arrayexpress
Project description:Characterization of the complete chloroplast genome of Tabernaemontana divaricata
