Comparative proteomic analysis provides insight into the molecular mechanism of vegetative growth advantage in allotriploid Populus

Though allotriploid poplar shows a salient vegetative growth advantage that impacts biomass and lumber yield, the proteomic data of Populus allotriploids have not been scrutinized for identifying the underlying molecular mechanisms. We conducted a large-scale label-free proteomics profiling of the 5th, 10th, and 25th leaves of allotriploids and diploids, and identified 4587 protein groups. Among 932 differentially expressed proteins (DEPs), 22 are transcription factors (TFs) that could regulate vegetative growth advantage in allotriploids. The DEPs involved in light reaction, Calvin cycle, and photorespiration, protein synthesis, sucrose synthesis, starch synthesis, and starch decomposition displayed elevated expression in Populus allotriploids. However, the DEPs functioning in sucrose decomposition, tricarboxylic acid (TCA) cycle, and protein degradation exhibited significantly downregulated expression. The alternations of these DEPs augmented efficiency of photosynthesis, carbon fixation, sucrose and starch accumulation, and decreased capacity of carbohydrate consumption, leading to larger volume of biomass and vigorous growth in Populus allotriploids.

Automated summary

The proteomic analysis of allotriploid poplar revealed elevated expression of proteins involved in photosynthesis, carbon fixation, sucrose, and starch accumulation, leading to increased biomass and growth advantage. Conversely, proteins related to sucrose decomposition, tricarboxylic acid cycle, and protein degradation showed significantly downregulated expression in allotriploids. This alternation in protein expression enhances the efficiency of key metabolic processes, ultimately resulting in the observed vegetative growth advantage and larger biomass in allotriploid poplar.