title: Proteomic Analysis Reveals Different Involvement of Embryo and Endosperm Proteins during Aging of Yliangyou 2 Hybrid Rice Seeds.
abstract: Seed aging is a process that results in a delayed germination, a decreased germination percentage, and finally a total loss of seed viability. However, the mechanism of seed aging is poorly understood. In the present study, Yliangyou 2 hybrid rice (Oryza sativaL.) seeds were artificially aged at 100% relative humidity and 40°C, and the effect of artificial aging on germination, germination time course and the change in protein profiles of embryo and endosperm was studied to understand the molecular mechanism behind seed aging. With an increasing duration of artificial aging, the germination percentage and germination rate of hybrid rice seeds decreased. By comparing the protein profiles from the seeds aged for 0, 10 and 25 days, a total of 91 and 100 protein spots were found to show a significant change of more than 2-fold (P< 0.05) in abundance, and 71 and 79 protein spots were identified, in embryos and endosperms, respectively. The great majority of these proteins increased in abundance in embryos (95%) and decreased in abundance in endosperms (99%). In embryos, most of the identified proteins were associated with energy (30%), with cell defense and rescue (28%), and with storage protein (18%). In endosperms, most of the identified proteins were involved in metabolism (37%), in energy (27%), and in protein synthesis and destination (11%). The most marked change was the increased abundance of many glycolytic enzymes together with the two fermentation enzymes pyruvate decarboxylase and alcohol dehydrogenase in the embryos during aging. We hypothesize that the decreased viability of hybrid rice seeds during artificial aging is caused by the development of hypoxic conditions in the embryos followed by ethanol accumulation.
authors.affiliation: Key Laboratory of Plant Resources, Institute of Botany, Chinese Academy of Sciences Beijing, China.
authors.forename: Ying-Xue
authors.initials: YX
authors.lastname: Zhang
authors.affiliation: Key Laboratory of Plant Resources, Institute of Botany, Chinese Academy of Sciences Beijing, China.
authors.forename: Heng-Heng
authors.initials: HH
authors.lastname: Xu
authors.affiliation: Key Laboratory of Plant Resources, Institute of Botany, Chinese Academy of Sciences Beijing, China.
authors.forename: Shu-Jun
authors.initials: SJ
authors.lastname: Liu
authors.affiliation: Hunan Hybrid Rice Research Center/State Key Laboratory of Hybrid Rice Changsha, China.
authors.forename: Ni
authors.initials: N
authors.lastname: Li
authors.affiliation: Key Laboratory of Plant Resources, Institute of Botany, Chinese Academy of Sciences Beijing, China.
authors.forename: Wei-Qing
authors.initials: WQ
authors.lastname: Wang
authors.affiliation: Department of Molecular Biology and Genetics, Aarhus University Flakkebjerg, Denmark.
authors.forename: Ian M
authors.initials: IM
authors.lastname: Møller
authors.affiliation: Key Laboratory of Plant Resources, Institute of Botany, Chinese Academy of Sciences Beijing, China.
authors.forename: Song-Quan
authors.initials: SQ
authors.lastname: Song
keywords: Yliangyou 2 hybrid rice; embryo; endosperm; proteome; seed aging