Proteomic Study of Differentially Expressed Proteins in Seeds between Parents and Offspring of Castor Bean (<i>Ricinus communis</i> L.)

Castor bean (Ricinus communis L.), is one of the top 10 oilseed crops in the world and, therefore, of high economic value. Hybridization is one of the most effective ways to breed new varieties with high yield, high oil content, and better stress resistance. Therefore, prediction of desired traits in castor hybrid offspring is particularly important. In this study, proteomic analysis was performed to identify differentially expressed proteins (DEPs) in seeds between castor hybrid offspring and their female (Lm female line aLmAB₂) and male parents (CSR·181). Among the DEPs upregulated in the seeds of hybrid offspring, the majority were related to seed yield and stress tolerance, while some were related to oil synthesis and fatty acid synthesis and metabolism in seeds. In other words, the hybrid offspring showed heterosis for seed yield, stress tolerance, oil synthesis, and fatty acid synthesis and metabolism when compared with their parents. Further, real-time quantitative polymerase chain reaction assays were performed on 12 genes encoding DEPs involved in oil synthesis, pollen abortion, yield, and stress tolerance of seeds. The results showed that the expression levels of the 12 genes were consistent with those of the DEPs.