Project description:Actinomycete genomes contain a plethora of orphan gene clusters encoding unknown secondary metabolites, and representing a huge unexploited pool of chemical diversity. The explosive increase in genome sequencing and the massive advance of bioinformatic tools have revolutionized the rationale for natural product discovery from actinomycetes. In this context, we applied a genome mining approach to discover a group of unique catecholate-hydroxamate siderophores termed as qinichelins from Streptomyces sp. MBT76. Quantitative proteomics statistically correlated a gene cluster of interest (qch) to its unknown chemotype (qinichelin), after which structural elucidation of isolated qinichelin was assisted by bioinformatics analysis and verified by MS2 and NMR experiments. Strikingly, intertwined functional crosstalk among four separately located gene clusters was implicated in the biosynthesis of qinichelins.
Project description:In previous work, cephalotaxine, harringtonine, homoharringtonine were shown to be accumulated differentially after various stimuli. Especially, after MeJA treatment, the concentration of 3 cephalotaxus alkaloids all showed decreasing. We speculated that the genes expressed lower after MeJA treatment might encode some enzymes responsible for the biosynthesis of cephalotaxus alkaloids. Therefore, choosing the sample treated with MeJA and the control sample for comparative iTRAQ analysis will greatly facilitate dissection of the genes involved in the biosynthesis of cephalotaxus alkaloids and even the acyl portions of cephalotaxus ester alkaloids. This approach is widely used for mining and identifying novel genes in the biosynthesis of secondary metabolites without genome data in plants.
