Heterosis profile of sunflower leaves: a label free proteomics approach.

Heterosis is the superior performance of heterozygous F1-hybrid plants compared with their homozygous genetically distinct parents. The proteome of leaves of one sunflower hybrid and its parental inbred lines was analyzed by label free LC-MS/MS. A total of 1998 proteins were identified. Among them 38 proteins indicated heterosis pattern in hybrid compared with midparents. The results showed an increment of photosynthesis capacity, assimilation rate, nitrogen fixation, cell growth and reducing in some energy-consuming processes like protein production, response to stresses and respiration. These results suggest that heterosis mechanisms increase input energy of plant with reinforcement of carbon fixation pathway and reduction in consumed energy toward production of superior hybrid. This study could help to better elucidate what mechanisms are involved in heterosis of sunflower leaves and what happens at proteome level. BIOLOGICAL SIGNIFICANCE: The current work describes the first study in which gel-free shotgun proteomics was used to compare the proteome of leaves of one sunflower hybrid to its parental inbred lines. In this study 1998 proteins were identified from sunflower leaves with label free nano LC-MS/MS. The numbers of 38 proteins significantly showed heterosis pattern. The comparison between hybrid and parental inbred lines showed that hybrid vigor is actually linked by emphasizing the assimilation rate and low energy consumption.