Proteomic profiling of foxtail millet hybrid Zhangzagu10 and its parent lines using iTRAQ-based technique

Abstract

Heterosis had been increasingly applied in crop production for nearly a century, but the molecular basis of it was poorly understood especially in foxtail millet (Setaria italica). Zhangzagu10 which derived from two-line hybrid breeding system has the characters of ultra-high yield, good stability and extensive disease and lodging resistance. To gain a better understanding of the molecular basis of S.italica heterosis, the isobaric tags for relative and absolute quantification based quantitative proteomic analyses was performed between S.italica hybrid Zhangzagu10 and it parents (male parent Zhangzagu10fu and female parent A2). A total of 4015 proteins were detected, among which 610/276 differentially expressed proteins (DEPs) between Zhangzagu10 and the female/male parent, respectively. The cluster analysis showed that the DEPs expression profiles of Zhangzagu10 were closer to those of the male parent. GO functional classification divided the DEPs into three functional categories (Cellular component, Biological process and Molecular function) and 26 subfamilies, among which three subfamilies had 100% difference between Zhangzagu10 and its parents. KEGG metabolic pathway exhibited significant enrichment of DEPs in Metabolic pathways, Carbon fixation in photosynthetic organisms and Photosynthesis. qRT-PCR verification confirmed the differential expression data and revealed that the expression level of 3 selected genes (such as peroxidase 5-like,G-type lectin S-receptor-like serine/threonine-protein kinase SD2-5,two-on-two hemoglobin-3, etc.) was higher in Zhangzagu10 than that in its male parent. The expression level of 7 selected genes (such as peroxidase 64-like, cysteine-rich receptor-like protein kinase 45, indole-3-acetaldehyde oxidase, etc.) was higher in Zhangzagu10 than that in its male parent, but significantly lower than that in A2. Thus, A2 can potentially optimise the agricultural qualities of Zhangzagu10. Taken together, we hope that this study provides valuable information for the further utilisation and study on the molecular mechanisms of heterosis in hybrid millet.