ObjectiveAlthough Populus allotriploid has a prominent vegetative growth advantages, the underlying molecular mechanisms have not yet been revealed and elucidated. This work was designed to investigate proteins differentially expressed in the two Populus allotriploid derived by different types of 2n female gamete and their parents. The results will provide the scientific foundation for Populus polyploidy selection and genetic improvement.

MethodThe iTRAQ proteomics approach was used in this study. The extracted proteins were digested using FASP method and identified by iTRAQ coupled with LC-MS/MS technology. Raw data were analyzed by Proteome Discoverer 1.3 search engine. Then the pathway analysis was conducted using GO and KEGG.

ResultA total of 1 472 proteins were identified and 202 proteins were detected as differentially expressed proteins. The ratio of differentially expressed proteins between FDR and SDR Populus allotriploid and the two parents varied from 2.0% to 10.1%. Compared with the female parent or male parent, the ratio of differentially expressed proteins in FDR Populus allotriploid was higher than in SDR Populus allotriploid. In particular, there was an expression level dominance bias toward the triploid progenitors. Further analysis showed that the differentially expressed proteins were significantly enriched in the pathways such as metabolic related, ribosomes, photosynthesis and response to stress.

ConclusionThe results indicated that plyploidization and hybridization could enhance photosynthesis, proteins synthetic and increased the resistance and adaptability of Populus polyploidy. All of these contribute to vegetative growth advantages in allotriploid plants.