ITRAQ-based Proteomics Analysis Of Alligator Weed (Alternanthera Philoxeroides L.) Root With Low Potassium Treatment

Potassium is closely related to plant growth and development,and is a quality index of various crops.It participates in a variety of biological pathways in plants and has a complex molecular regulatory network.Alligator weed(Alternanthera philoxeroides)has a strong ability to adapt to low potassium treatment.Proteomic changes in response to this stress are largely unknown in alligator weed.In this study,we investigated physiological and molecular mechanisms under using isobaric tags for relative and absolute quantitation to characterize proteomelevel changes in this plant.It provides a valuable insights of molecular mechanism underlying low potassium treatment response in alligator weed roots and afords a vital basis to further study potassium nutrition molecular breeding of other plant species.The main rsults were listed as the following:1.The root of the physiological and biochemical indexes of Alligator weed in different periods.The color of root began to turn yellow.After 15 days of treatment,the root color was more obvious in the control group.Proline and Malondialdehyde were increased after low potassium treatment.2.The comparative proteomic analysis suggested a total of 375 proteins were diferential abundance proteins.Bioinformatics analysis found that differential abundance proteins were mainly concentrated in carbohydrate and energy metabolism,secondary metabolism,signal sensing and transformation,stress response,protein synthesis,protein degradation pathways,etc.3.The twelve proteins of ubiquitin pathway related were identiied in the ubiquitination pathway,among them 11 proteins were up-regulated.Including ubiquitin activating enzyme,ubiquitin carboxy terminal hydrolase,26 S protease regulatory subunit,etc.Western blotting was used to detect the level of lysine ubiquitination.The results showed that the ubiquitination of small molecular weight proteins increased significantly after low potassium treatment.4.The proteomic results were veriied by western blot assays and quantitative real-time PCR.Western blot results showed that heat shock protein 70(HSP70),cytoplasmic ascorbate peroxidase and Beta-cyanoalanine synthase(Beta-CAS)changed consistent with iTRAQ results.Twelve proteins were randomly selected and the expression levels of the corresponding genes were determined by qRT-PCR.Ten genes expression patterns showed the same trend as protein abundance.including ascorbate peroxidase,heat shock protein 70,Beta-cyanopropylamine.Acid synthase,etc.Calmodulin-binding transcription activator 2 and elongation factor showed opposite patterns between transcription level and protein abundance.