Project description:Plant defensins are a broadly distributed family of antimicrobial peptides which have been primarily studied for agriculturally relevant antifungal activity. Recent studies have probed defensins against gram negative bacteria revealing evidence for multiple mechanisms of action including membrane lysis and ribosomal inhibition. In this study, a γ-core motif synthetic analog ( Atr-DEF2(G39-C55) ) of Amaranthus tricolor DEF2 (Atr-DEF2) is used to probe plant defensin antibacterial mechanism of action via proteomics.
Project description:Traditional medicinal plants are rich reservoirs of antimicrobial agents, including antimicrobial peptides (AMPs). Herein, Amaranthus tricolor AMPs predicted in silico are identified via proteomics profiling. Bottom-up proteomics identified seven novel peptides spanning three AMP classes including lipid transfer proteins, snakins and defensins. Characterization via top-down peptidomic analysis of Atr-SN1, Atr-DEF1, and Atr-LTP1 revealed unexpected proteolytic processing and enumerated disulfide bonds. These results highlight the potential for integrating AMP prediction algorithms with complementary -omics approaches to accelerate characterization of biologically relevant AMP peptidoforms.
Project description:Resistance to synthetic auxin herbicides was recently confirmed in a population of Amaranthus powellii. Following field studies, an RNA-seq experiment was devised to determine the mechanism of resistance to MCPA (a synthetic auxin herbicide) by comparing the level of gene expression of genes in the auxin pathway between the resistant and a susceptible population of Amaranthus powellii. The results identified several differentially expressed genes (DEGs) in the auxin pathway that were significantly downregulated in the resistant samples indicating that the resistance mechanism may be linked to a target site modification.