Proteomic Changes Between Populus Allotriploids and Diploids Revealed Using an iTRAQ-based Quantitative Approach.

Background: Polyploid breeding is a powerful approach for Populus genetic improve-ment because polyploid trees have valuable characteristics, including better timber quality and a higher degree of stress resistance compared with their full-sib diploids. However, the genetic mech-anism underlying this phenomenon remains unknown.

Objective: To better understand the proteomic changes between Populus allotriploids and diploids, we examined the proteomic profiles of allotriploid and diploid Populus by iTRAQ labeling coupled with two-dimensional liquid chromatography and MALDI-TOF/TOF mass spectrometry (MS).

Method: iTRAQ labeling coupled with two-dimensional liquid chromatography and MALDI-TOF/TOF mass spectrometry (MS).

Results: Between the Populus allotriploid and the full-sib diploid, 932 differentially expressed proteins (DEPs) were identified. These DEPs were primarily involved in stress, defense, transportation, transcriptional and/or translational modification, and energy production. The pathway analysis indi-cated that most of the DEPs were implicated in carbohydrate transport and metabolism, nitrogen me-tabolism and glycolysis, and the ribosome assembly pathway. These data suggest high protein di-vergence between Populus allotriploids and diploids, and rapid changes during hybridization.

Conclusion: The results provide new data for further understanding of the mechanisms of polyploid trees that generally display increased height growth compared with their full-sib diploids.